ChemCommChemical Communicationsrsc.li/chemcomm

ISSN 1359-7345

FEATURE ARTICLEAn-Hui Lu et al.Progress in selective oxidative dehydrogenation of light alkanes to olefins promoted by boron nitride catalysts

Volume 54 Number 78 7 October 2018 Pages 10925–11056

10936 | Chem. Commun., 2018, 54, 10936--10946 This journal is©The Royal Society of Chemistry 2018

Cite this:Chem. Commun., 2018,

54, 10936

Progress in selective oxidative dehydrogenation of lightalkanes to olefins promoted by boron nitride catalysts

Lei Shi, Yang Wang, Bing Yan, Wei Song, Dan Shao and An-Hui Lu *

Conversion of light alkanes into industrial chemical olefins via oxidative dehydrogenation (ODH) is

a promising route because of favorable thermodynamic and kinetic characteristics, but encounters

difficulties in selectivity control for olefins because of over-oxidation reactions that produce a substantial

amount of undesired carbon oxides. Compared to widely-developed metal oxide-based catalysts,

functionalized boron nitride has recently been shown as a competitive system in the ODH of light alkanes

because of its more superior selectivity toward olefins as well as negligible formation of CO2. It is also

characterized by high productivity to light olefins, remarkable catalyst stability, superior anti-oxidation

ability, and excellent thermal conductivity. This feature article highlights the recent developments in

applying boron nitride towards the ODH reaction of light alkanes. By correlating structural character with

catalytic behavior, we expect to provide more insights into the catalytic nature of boron nitride-based

materials in ODH reactions. Finally, we envisage perspective directions for boron-based ODH catalysts.

1. Introduction

Light olefins (especially C=2–C=

4) are the most important feed-stocks (4250 million metric tons per year) employed in theproduction of a vast array of chemicals, including polymers,oxygenates, and other derivatives. Traditionally, C2–C4 olefins areproduced through either the cracking of petroleum-derived hydro-carbons or a multistage coal-based methanol-to-olefins process,both involving extensive energy consumption and enormous carbonemission.1,2 The recent increasing availability and low-cost of

worldwide shale gas and natural gas resources, which containconsiderable amounts of light alkanes (C2–C4), has stimulated aquick technical shift to obtain commodity light olefins fromgas-based dehydrogenation routes.3,4

Direct dehydrogenation can be used by industry for the produc-tion of light olefins like ethylene, propylene, and butylenes, andso on.5 However, these processes are reversible and suffer fromseveral limitations, such as, thermodynamic restriction on con-version and selectivity, strong endothermic main reaction andnecessity to supply heat at high temperature, coke formation andresulting catalyst deactivation.6 In contrast, oxidative dehydrogena-tion (ODH) overcomes most of the obstacles existing in a directdehydrogenation process. Because of the introduction of oxygen,there are no coking and equilibrium-limited problems; the

State Key Laboratory of Fine Chemicals, School of Chemical Engineering,

Dalian University of Technology, Dalian 116024, P. R. China.

E-mail: anhuilu@dlut.edu.cn

Lei Shi

Lei Shi received his PhD degree inphysical chemistry from XiamenUniversity, China in 2013, andthen joined Prof. Lu’s group atDalian University of Technology(DUT), China, as a postdoctoralfellow. In 2016 he was promotedto an Associate Professor of DUT.His current research concentrateson catalytic conversion of lightalkanes.

Yang Wang

Yang Wang, born in 1990, obtainedhis BSc and MSc degrees fromDalian University of Technology,China. He is currently working onhis PhD thesis in the group of Prof.Dr A.-H. Lu and focuses on thedevelopment of new catalysts toactivate and convert methane.

Received 9th June 2018,Accepted 13th August 2018

DOI: 10.1039/c8cc04604b

rsc.li/chemcomm

ChemComm

FEATURE ARTICLE

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

.

View Article OnlineView Journal | View Issue

This journal is©The Royal Society of Chemistry 2018 Chem. Commun., 2018, 54, 10936--10946 | 10937

reaction becomes exothermic and is able to proceed at lowertemperature; furthermore, the rate of oxidation reaction isseveral orders of magnitude faster than that of the directdehydrogenation.7–9 Although intensive efforts have been madein this field, selectivity control for olefins in an ODH reaction ofC2–C4 alkanes still remains an unsolved challenge. The mainreason is that the alkane activation generally requires severeconditions, under which the consecutive oxidation of reactiveolefin products to carbon oxides can easily occur, leading to lowselectivities of olefin products at reasonably high conversions.

Recently, Hermans’s group,10–12 Lu’s group13–16 and Su’sgroup17,18 independently disclosed that boron nitride (BN) couldefficiently catalyze the ODH of C2–C4 alkanes to correspondingolefins with impressive selectivity, and with only negligible CO2

formation. Such a novel catalyst system addresses the difficulty ofselectivity control for olefins that has long existed in the ODHprocess because of the over-oxidation reactions that produce asubstantial amount of undesired carbon oxides. In this FeatureArticle, we highlight the recent progresses in boron nitridematerials as the highly selective catalysts for the ODH reactionof light alkanes. New insights into the catalytically active sites anddriving force of boron nitride in the ODH reaction are discussed.

2. Brief summarization of previousdevelopments of ODH catalysts

Before going into the new developments using boron nitrideas the ODH catalyst, the related achievements obtained in thelast decades are presented briefly in the following paragraphs.

The industrialized process for ethylene production is steamcracking of petroleum- and/or natural-gas-derived hydrocarbonsat high temperatures (800–1000 1C), typically with B85% selec-tivity at B60% conversion of ethane. A notable amount of carbondeposit formed under such harsh reaction conditions wouldcover the alloy tubes and halt the reaction, thus requiringfrequent regeneration for cleaning the deposited coke. TheODH of ethane to ethylene, a good alternative to the steamcracking process, has been widely developed using a metaloxide catalyst in the past decades. On the basis of B60% con-version, Table 1 compares the representative catalysts reportedin an ethane ODH reaction.19–39 Catalytic systems that giveoutstanding performance mainly include mixed molybdates(MoVTeNbOx) and alkaline earth oxychlorides (Mg/Dy/Li/Cl/O).The MoVTeNbOx catalysts, prepared by hydrothermal synthesis,are extremely active and highly selective in the ODH ofethane. On the best catalyst, selectivity higher than 80% atethane conversion levels greater than 80% is obtained atrelatively low reaction temperatures (340–400 1C).28 However,both chemical complexity and structural instability of poly-valent and multi-component metal oxides hinder the develop-ment of this catalyst system. Another system giving excellentperformance is Li/Dy/Mg/Cl/O,32 but the operating tempe-rature is usually higher than 600 1C, and the corrosion of thepipeline and damage to the environment by halogen chlorideare unavoidable. In addition, ethylene productivity achievedover most catalysts is lower than 1 gC2H4

gcat�1 h�1. That is the

limit value below which the productivity is too low to beinteresting for commercial applications.40 Therefore, the devel-opment of novel catalyst systems with simple composition and

Bing Yan

Bing Yan, born in 1990, obtainedhis BSc degree from Inner MongoliaUniversity of Science and Technol-ogy, then MSc degree from DalianPolytechnic University, China. Heis currently working on his PhDthesis in the group of Prof.Dr A.-H. Lu and focuses on theoxidative dehydrogenation of lightalkanes with metal-free catalysts.

An-Hui Lu

An-Hui Lu received his PhDdegree from the Institute of CoalChemistry, Chinese Academy ofSciences in 2001. He workedas a Postdoctoral fellow andAlexander von Humboldt fellowin the group of Prof. F. Schuthat the Max-Planck-Institute furKohlenforschung. In 2005, hewas promoted to a group leaderat the same institute. He iscurrently a professor at the StateKey Laboratory of Fine Chemicals,School of Chemical Engineering,

Dalian University of Technology and has been since 2008. Since2015, he has been appointed as the Dean of the School of ChemicalEngineering, and has been the vice director of the State KeyLaboratory of Fine Chemicals since 2017. He received the NationalScience Fund for Distinguished Young Scholars of China (2012),Cheung Kong Scholar by the Ministry of Education of China (2015).He has authored and co-authored more than 170 papers withcitation over 12 000 times, with an H-index of 53. His researchinterests include synthesis of porous materials for heterogeneouscatalysis, adsorption, energy storage and conversion.

Feature Article ChemComm

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

10938 | Chem. Commun., 2018, 54, 10936--10946 This journal is©The Royal Society of Chemistry 2018

outstanding performance is still highly desired to push forwardthe progress for ethane ODH.

Propane dehydrogenation (PDH) has supplied B5% ofglobal propylene, which will anticipatively increase to 20% by2020.41 As an alternative to industrialized PDH, the ODH ofpropane to propylene has long been the focus of researchers’attention. In the past few decades, catalytic systems givinggood performance in propane ODH are those based on transi-tion metal oxides (V/MgO, V2O5/SiO2, MoO3/K-SiO2-TiO2, etc.),alkaline earth or rare earth oxides and oxychlorides (Li/Dy/MgO,Dy/Mg/Li/Cl/O, etc.).40 However, even after decades of research,selectivity to propylene remains too low to be commerciallyattractive since electron-rich olefin easily reacts with the surfaceof metal oxide catalysts, resulting in the cleavage of the C–Cbond through a consecutive oxygen insertion and thus formingthe undesired over-oxidation product (CO2). As summarizedin Table 2 for these well-developed metal oxide catalysts, theover-oxidation product, CO2, constitutes a very high proportionof the products, typically around 20% and in some cases evenup to 50%, at conversion levels of B20%, a typical value ofindustrial interest.42 There is evidently an urgent need to developnew catalysts that can produce olefins with high selectivity underthe severe conditions of alkane activation. Furthermore, mostcatalysts reported in the literature exhibit olefin productivitiesless than 1 golefin gcat

�1 h�1, by far being insufficient to satisfyeconomic feasibility.40

Traditionally, isobutylene is used to produce polyisobutylene,butyl rubber, and polymethyl methacrylate. Nowadays, marketingdemand for isobutylene has considerably increased, which hasbeen a consequence of its application for the production ofmethyl t-butyl ether (MTBE), an important octane numberenhancer for gasoline. According to statistics, about two thirdsof isobutylene is obtained from isobutane by its dehydrogena-tion, which encounters thermodynamic limitations and needs

high energy requirements.72 Thus, the ODH of isobutane toisobutylene becomes an attractive process. However, catalyticselectivity control is still difficult since for an alkane–oxygenmixture, the thermodynamically favored products are CO2 andH2O. To date, catalytic systems exhibiting good selectivity towardsisobutylene are chromia-based catalysts, metal pyrophosphates,and polyoxometalates (Table 3).73–85 Many studies reported thatcarbon materials, such as activated carbons, carbon xerogels, andgraphitic carbons, are capable of producing isobutylene fromisobutane under oxygen atmospheres,86 but have a very highproportion of COx formation. Also, carbon materials are easilyoxidized to CO2 under high-temperature oxidative conditions.Being different from the ODH of isobutane, nanostructuredcarbons were shown as a competitive system to the metal oxidecatalysts in the ODH of n-butane. As exemplified by Zhang et al.,carbon nanotubes with modified surface functionality displayedan enhanced selectivity to butylene, especially butadiene com-pared to metal-based catalysts.87

3. Recent breakthrough in the ODHreaction of light alkanes promoted byboron nitride

Boron nitride (BN) is a chemical compound consisting of equalnumbers of boron (B) and nitrogen (N) atoms. They have threecrystalline forms: graphite-like hexagonal BN (h-BN), diamond-like cubic BN (c-BN), and wurtzite BN (w-BN).88 Among them,h-BN, the most stable BN phase under standard conditions, hasbeen extensively applied in the field of physics, electronics andaerospace as sealing materials, taking the advantage of excel-lent anti-oxidation property and structural stability.89 In thefield of heterogeneous catalysis, h-BN is generally considered tobe chemically inert, and has been merely used as a support for

Table 1 Brief summary of the catalytic results of the representative catalysts for the ODH of ethane

CatalystsTemp[1C]

WGSV[gC2H6

gcat�1 h�1]

Conversionof C2H6 [%]

Selectivity [%]Productivity[gC2H4

gcat�1 h�1] Ref.C2H4 CO CO2

Steam cracking 900–950 — 60.0 85.0 — — — Ranzi19

PtSn/Al2O3 + H2 73.0 83.0 — — —Al/Pd/Al2O3-ALD 675 1.4 40.0 45.0 12.0 7.0 0.25 Stair20

Ni/K-Y 600 7.8 13.8 72.9 7.6 19.5 0.78 Weitz21

Ni–Ti–Ox 350 0.2 33.0 76.0 — 24.0 0.05 Basset22

Ni–Sn–Ox 350 1.9 12.2 88.5 — 11.5 0.19 Solsona23

NiO/TiO2 450 15.0 17.2 85.4 — 14.6 2.20 Nieto24

NiNbOx 400 8.9 66.0 70.0 — 30.0 0.46 Lemonidou25,26

V–Mg–O 600 — 43.0 44.7 33.5 12.6 — Ruckenstein27

MoVTeNbOx 400 0.2 80.1 80.3 12 5.3 0.11 Galbet,28 Wan29

MoVTeNbBiOx 450 — 81.0 86.0 — 14.0 — Ishchenko30

5%Mo–TiO2 550 1.3 55.2 92.1 — 7.9 0.66 Bal31

Mo–V–Nb–Ox 35.0 90.0 — 10.0 0.41Ni–Ta–Ox 62.0 68.0 — 32.0 0.55LiKCl/MgDyOx 650 0.8 50.0 96.0 — 4.0 0.38 Lercher32

LiKBr/MgDyOx 98.0 81.0 — 19.0 0.64SrFeO3�xClx 560 2.4 54.0 69.0 — 31.0 0.89 Au33

LiCl/MnOx/PC 650 — 66.1 87.4 3.6 6.3 — Xu34

CeO2-ZrO2-NANF 500 2.1 40.3 60.6 — — 0.51 Lu35

YBa2Cu3O7�0.21F0.16 680 2.4 84.1 81.8 — 10 1.64 Au36,37

La0.6Sr0.4FeO3�0.048 660 2.4 55.3 45.1 — 57.5 0.59Sr1.0La1.0Nd1.0Ox 700 9.6 65.2 71.2 3.6 17.3 4.48 Baerns38,39

ChemComm Feature Article

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

This journal is©The Royal Society of Chemistry 2018 Chem. Commun., 2018, 54, 10936--10946 | 10939

a long time.90,91 Also, Fu and Bao confirmed that the h-BN covercan be used as a promoter to tune molecule–metal interaction byenhancing the metal-catalyzed reactions.92,93 Beyond that, it israther rare to find any report directly investigating the catalyticactivity of boron nitride itself.

3.1 Oxidative dehydrogenation of propane

Grant et al. have recently reported that both h-BN and BNnanotubes (BNNTs) are able to catalyse the oxidative dehydro-genation of propane.10 The use of boron nitride materialsresulted in extraordinary selectivity to propylene and ethylene(Fig. 1A). For example, h-BN afforded 79% selectivity to

propylene and 12% selectivity to ethylene at 14% conversion ofpropane. The proportion of COx only accounts for B9%, far lowerthan that over traditional VOx/SiO2 catalysts at 9% propane con-version (Fig. 1B). They furthermore verified that the catalytic activityof the h-BN remained stable for at least 32 hours on stream. Bothh-BN and BNNTs had similar product distribution; however,BNNTs exhibit a conversion rate of propane (kgC3H6

kgcat�1 h�1)

more than one order of magnitude higher than that of h-BN(Fig. 1C). This high activity and selectivity resulted in a substantialenhancement in the observed propylene productivity.

Further kinetic insights were provided by the authors.10

Molecular oxygen was required for propane conversion using

Table 3 A summary of the representative catalysts used for the ODH of isobutane

CatalystsTemp[1C]

WGSV[gC4H10

gcat�1 h�1]

Conversion[%]

Selectivity [%]Productivity[gC4H8

gcat�1 h�1] Ref.C4H8 C3H6 CO CO2 Others

CrOx/Al2O3 250 0.9 16.0 48.0 — 9.0 43.0 — 0.07 Grzybowska73

Cr-VOx/meso-CaO 540 3.1 19.0 79.0 — — 6.4 15.6 0.35 Dai74

CrOx/La2(CO3)3 230 — 10.0 71.0 — — 29.0 — — Hoang75

CrOx/ZnAlLaO 580 0.5 43.7 84.0 2.0 — 9.0 5.0 0.18 He76

K8P2W17CuO61 426 0.7 17.2 61.0 8.0 — 26.0 5.0 0.07 Trovarelli77

V-MCM-41 550 16.4 15.0 47.0 23.0 — 17.0 13.0 1.31 Sulikowski78

MoO3 420 1.2 7.4 58.2 7.7 10.2 5.2 18.7 0.05 Kan79

K/b-NiMoO4 480 0.2 8.1 69.2 — 6.2 12.6 12.0 0.01 Kaddouri80

NiO-POM 500 1.5 21.0 71 — — 18.0 11.0 0.23 Wang60

CePO4 550 0.7 10.2 86.4 6.7 3.0 2.0 1.9 0.06 Takita81

CeP2O7 500 3.1 20.5 70.8 14.0 8.5 2.9 3.8 0.45 Al-Zahrani82

b-Mn2V2O7 450 2.3 9.6 45.8 — 44.5 9.7 — 0.10 Burns83

Activated carbon 375 3.1 15.0 44.0 — — — — 0.20 Velasquez84

450 4.7 17.0 48.0 — 16.0 35.0 — 0.38 Kozłowski85

Table 2 A summary of the catalytic performance of the representative catalysts for ODH of propane

CatalystsTemp[1C]

WHSV[gC3H8

gcat�1 h�1]

Conversionof C3H8 [%]

Selectivity [%]Productivity[golefin gcat

�1 h�1] Ref.C3H6 C2H4 CO CO2

Pt8–10/SnO/Al2O3 550 — 25.7 68.0 0.0 — 32.0 — Vajad43

V–Mg–O 500 11.8 24.0 57.5 — 27.2 15.3 1.45 Kondratenko44

V2O5/SBA-15 550 14.1 26.3 65.4 6.2 — 25.2 2.47 Cao45

VOx-MCM-41 550 8.8 16.5 45.5 — 33.8 14.9 0.59 Nieto46

V2O5/KIT-6 600 4.7 25.0 48.8 16.1 10.7 17.9 0.68 Wei47

F–V2O5/SiO2 540 3.0 14.8 64.2 — — — 0.27 Xie48

Na–V2O5/Al2O3 500 5.0 20.2 50.7 — — 49.3 0.45 Lemonidou49

ZrV0.15Ox 540 8.8 24.4 39.9 — — 45.6 0.9 Lu50

Mg/Dy/Li/Cl/O 600 1.2 20.1 51.6 28.2 — 17.3 0.16 Lefferts51

Li/MgO 600 1.2 17.3 44.5 31.8 3.7 13.6 0.14 Lefferts52,53

Sol–gel Li/MgO 650 24.1 13.0 80.0 — 20 2.32 Seshan54

MoO3/K-Si–TiO2 450 1.6 22.0 63.2 — 21.8 10.5 0.33 Ozkan55

SrVMoOx/Al2O3 500 5.3 22 67.8 — — 28 0.75 Abasaeed56

NiMoO4 560 1.0 26.6 60.4 — — 36.0 0.15 Grasselli57

Meso-NiMoO4 475 3.1 18.2 63.9 — 10.8 21.1 0.35 Gaigneaux58

Mesoporous NiO 500 6.9 21.9 47.1 2.0 — 50.5 0.71 Wan59

NiO–POM 450 0.5 23.0 65.0 0.0 6.4 27.0 0.07 Wang60

CeNbNiOx 350 19.7 22.7 49.1 0.2 — 50.7 1.91 Wan61

Cr2O3/Al2O3 450 2.4 16.7 54.1 — — 45.9 0.19 Jibril62

Cr2O3/SBA-15 550 4.9 20.5 33.2 25.9 16.7 22.2 0.52 Cao63

Cr2O3/MCF 550 4.9 32.9 41.8 15 16.4 24.0 0.80Cr–Al Clay 450 1.2 26.7 38.0 — — 62.0 0.11 Leon64

Ga-MFI 600 14.2 14.1 28.7 — 29.2 25.7 0.51 Sulikowski65

Cs0.9H2.1PW12O40 380 0.1 19 38 — 42 7.6 0.01 Wan66

Fe/Ca5(PO4)3OH 550 8.5 17.5 34.2 11.4 — 44.2 0.64 Ziyad67

Nb2O5/CeO2 400 3.5 19.2 26.3 — 14.1 55.9 0.17 Huang68

CMK-3 450 1.2 20.7 55.4 0.5 — 40.4 0.13 Kustrowski69

BxCN 350 0.6 7.5 81.3 — — — 0.04 Bordoloi70

P2O5-Nanodiamond 500 3.5 23 45 — — 45 0.12 Su71

Feature Article ChemComm

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

10940 | Chem. Commun., 2018, 54, 10936--10946 This journal is©The Royal Society of Chemistry 2018

BN materials. The conversion rate of propane using h-BNindicates oxygen activation on the BN surface and second-order dependence with respect to partial pressure of propane.This kinetic behavior was different from traditional supportedvanadia catalysts that followed a Redox mechanism, in whichrate-determining substrate oxidation was followed by fast re-oxidation of the surface by oxygen.

A combination of X-ray photoelectron spectroscopy (XPS),attenuated total reflectance-infrared (ATR-IR), and diffusereflectance infrared Fourier transform spectroscopy (DRIFTS)measurements showed the emergence of B–OH and B–O func-tional groups for the spent h-BN material in the ODHP reaction(Fig. 2A and B). With the assistance of density functional theory

(DFT) calculations, the authors compared the vibrational fre-quencies for a set of OH-terminated zigzag and armchair edges(Fig. 2C), and deduced that the OH-stretching features for thespent h-BN material resulted from the armchair edge.

From the combination of catalytic activity, spectroscopicdata, and DFT simulations and in line with the observed oxygen-dependence of the kinetics, the authors proposed that an oxygenmolecule bonded to one B and one N [an oxygen-terminatedarmchair edge of BN ({B–O–O–Nz)] acts as an active site forthe ODH of propane.10 They suggested that the dehydrogena-tion was initiated by the abstraction of a hydrogen atom from asecondary carbon of propane by the {B–O–O–Nz sites, breakingthe O–O bond while forming a B–OH species and one nitroxylradical. A second abstraction of a hydrogen atom from aprimary carbon followed another radical rebound, and createda di-propoxyl intermediate. Desorption of propylene and thereorganization of hydrogen atoms along the edge form water asa side product.

During the same period, our group independently disclosedthat edge-hydroxylated boron nitride can efficiently catalyzeoxidative dehydrogenation of propane and ethane to the corres-ponding olefins with an impressive selectivity, but with onlynegligible CO2 formation.13,16 In the case of ODH of propane,the h-BN with edge-hydroxylation treatment (BNOH) exhibitedhigh conversion of propane (20.6%) and selectivity (80.2%) ofpropylene. Taking the equally important product ethylene intoaccount, the selectivity for light olefins was up to 90.9%.Ethylene as the main by-product indicated the presence ofC–C cleavage in the ODH reaction.10,94,95 More significantly,the formation of CO2 (0.5%) was considerably lower than thatof the traditional ODH processes (10–50% CO2).16

The control experiment with a feed gas of propylene andmolecular oxygen further showed that a boron nitride catalystdid not oxidize propylene, and thus prevented its over-oxidationto CO2. Hydroxylated boron nitride (BNOH) also exhibited anolefin productivity of 6.8 golefin gcat

�1 h�1, which was far higherthan those of metal oxide catalysts, and stability for at least300 hours. These results indicate that edge-hydroxylated boronnitride catalysed ODH of propane is a promising process forindustrial implementation.

Furthermore, dominantly exposed zig-zag boron-terminatededges and the co-existence of B–O–B and B–OH groups at theseedges of the boron nitride with edge-hydroxylation treatment

Fig. 1 (A) Selectivity to propylene as a function of propane conversion in the ODH reaction, comparing previously reported data from representativecatalysts to h-BN and BNNTs. (B) Comparisons of product selectivity between VOx/SiO2 (XC3H8

= 5.8%); h-BN (XC3H8= 5.4%); and BNNTs (XC3H8

= 6.5%).(C) Comparisons of propylene productivity as a function of C3H8 conversion between VOx/SiO2, h-BN, and BNNT. Reprinted from ref. 10 with permission.

Fig. 2 (A) ATR spectroscopic measurement of fresh, air-treated, andspent h-BN. The broad feature at B3200 cm�1 and the sharp signal at1190 cm�1 are assigned to OH-stretching and B–O stretching vibrations,respectively. (B) DRIFTS measurement of fresh (black line) and spent h-BN(blue line). The vibrations at B3420 and 3250 cm�1 are assigned to singleand concerted OH-stretching, respectively. (C) Calculated structures ofoxygen-terminated zig-zag and armchair BN edges. Important calculatedIR features for these structures are included to the right of each respectivefigure. Boron = green, nitrogen = silver, oxygen = red, hydrogen = white.Reprinted from ref. 10 with permission.

ChemComm Feature Article

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

This journal is©The Royal Society of Chemistry 2018 Chem. Commun., 2018, 54, 10936--10946 | 10941

were identified using advanced microscopic and spectroscopictechniques, including aberration-corrected transmission electronmicroscopy (TEM), K-edge EELS, X-ray photoelectron spectroscopy(XPS), two-dimensional multiple-quantum MAS NMR, and infra-red spectroscopy (Fig. 3).

In the combination of in situ spectroscopy, kinetic analysisand isotope tracer, our emphasis was placed to reveal the originof catalytic activity of boron nitride materials (Fig. 4). The out-come suggested that the oxygen-containing edge boron speciesthemselves had no catalytic activity for C–H cleavage in pro-pane. In situ IR analysis indicated that the –OH groups inter-acted with molecular oxygen and incorporated into the reactionnetwork. Isotope-labelling measurements provided further insightinto this process, where the hydrogen atoms in the B–OH groupwere abstracted during the ODH reaction.

The kinetic analysis confirmed that the reaction order ofoxygen was close to 0.5, indicating a dissociative adsorption of

molecular oxygen in the reaction process. Meanwhile, an18O isotope tracer study demonstrated that an oxygen exchangebetween the surface oxygen atoms in the B–OH group andmolecular oxygen occurred in the reaction process. Theseobjective findings allowed us to conclude that the B–OH groupsat the edge of boron nitride were initially oxidized by molecularoxygen, and then triggered the dehydrogenation reaction ofpropane.

The reaction of propane was second order, and the normalkinetic H/D isotopic of 1.4–1.5 was observed, indicating that theactivation of propane determined the total reaction rate. Basedon the above observations, a relatively simple reaction pathway(Fig. 5) was proposed including a redox reaction cycle.16 TheB–OH sites initially reacted with molecular oxygen, leading tothe production of B–O–O–B intermediates (oxidation step). TheB–O–O–B species further abstracted the hydrogen atoms frompropane, forming C3H6 and H2O (reduction step), and thenrecovered to B–OH sites with the assistance of water.

Later, Grant et al. reported that the boron-containing mate-rials: boron carbide (B4C), titanium boride (TiB2), nickel boride(NiB), cobalt boride (Co2B/Co3B), hafnium boride (HfB2), tung-sten boride (WB), and elemental boron all catalysed the ODH ofpropane and showed the same product trends in their productdistributions as boron nitride.96 High selectivity to propylenewas achieved using these B-containing catalysts, with the majorbyproduct being ethylene, rather than COx. They therefore con-cluded that boron was the necessary element to achieve higholefin selectivity. Based on the results from X-ray photoelectronand infrared spectroscopy, they suggested the formation of ananalogous surface-stabilized BOx active site for all tested boridecatalysts. This observation disproves previous mechanistichypotheses that edge sites on the boron nitride would be theactive sites.

A recent work from Eswaramoorthy et al. shows that high-surface-area h-BN can enhance the ODH performance of pro-pane. For example, the selectivity of propylene and ethylene wasobtained as high as 53 and 18%, respectively, at a propaneconversion of 52%. However, the catalytic activity of high sur-face area h-BN was retained for only 5 h in propane ODH. Theaddition of ammonia could regenerate the catalytic activity andmaintain stable activity for more than 100 hours.97

Boron nitride materials have high thermal conductivity(33 W K�1 m�1), and thus facilitate the removal of the reactionheat in a highly exothermic ODH reaction of light alkanes,which is crucial to the commercial application of boron nitride.Using h-BN as a propane ODH catalyst, Lin and Wang et al.revealed the heat transfer and the temperature profile in thefixed-bed reactor based on the computational fluid dynamics(CFD) calculations, which showed a visual temperature profilein the catalyst bed.98 A comparison was also made using theVOx/g-Al2O3 catalyst in a micro-tubular reactor with an innerdiameter of 6 mm. The results exhibited that the catalyst bedtemperature increased by less than 1 1C in the h-BN catalyst bedwhich was much smaller than that (8 1C) in the VOx/g-Al2O3

catalyst bed at a similar propane conversion (25%) using amicro-tubular reactor with a diameter of 6 mm (Fig. 6A�C).

Fig. 3 Structural characterization of the BNOH catalyst. (A) Aberration-corrected TEM images along the [001] direction and FFT image of the (a)area. (B) HAADF-STEM image (top left), boron and nitrogen K-edge EELSspectrum (right), and B/N ratio (bottom left) calculated by EELS spectrum.(C) B1s, N1s and O1s XPS spectra. (D) 2D 11B MQ MAS NMR and 1H MASNMR (inset) spectra as well as structural model (inset) of the BNOH edge.Reprinted from ref. 13 with permission.

Fig. 4 (A) Kinetic analysis of propane ODH over the BNOH catalyst.(B) FT-IR spectra of B–OH vibration over the BNOH catalyst under C3H8

and C3H8/O2/He atmospheres. (C) Mass spectra of C3H6, H2O, HDO andD2O species upon pulsing C3H8 and O2 onto the deuterated BNOH(D)catalyst. (D) Mass spectra of C3H6, H2

16O and H218O species during pulsing

C3H8 and 18O2 onto the BNOH catalyst. Reprinted from ref. 13 withpermission.

Feature Article ChemComm

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

10942 | Chem. Commun., 2018, 54, 10936--10946 This journal is©The Royal Society of Chemistry 2018

The high thermal conductivity of the h-BN catalyst couldmaintain isothermal operation in such a micro-tubular reactorat even up to 590 1C with a higher propane conversion of 45%.However, a hotspot of 45 1C temperature gradient wasinevitable in the VOx/g-Al2O3 catalyst bed even at relativelylow temperature of 520 1C. Even in an industrially relevantreactor with an inner diameter of 60 mm, a uniform tempera-ture profile can be maintained using the h-BN catalyst bed(1.5 1C) as opposed to a temperature gradient of 47 1C in theVOx/g-Al2O3 catalyst bed (Fig. 6D). The significantly improvedtemperature control in the h-BN catalyst bed can lead to highselectivity towards olefin while minimizing COx formation. Theseresults reported here provide useful information for potentiallyindustrial application of the h-BN catalyst in propane ODH toolefin production.

3.2 Oxidative dehydrogenation of butane

The study from Hermans’s group shows that h-BN is an out-standing catalyst for selective oxidative dehydrogenation ofn-butane and isobutane.11 Amongst the ODH catalysts forn-butane and isobutane reported in the literature,73,87 h-BNshowed some of the highest olefin selectivities at similar levels

of conversion. Typically, the combined selectivity of all formedolefins, i.e. ethylene, propylene, butylenes and isobutylene, wasaround 90% at B10% alkane conversion over the h-BN catalyst,while the reference P-CNT and Cr2O3/Al2O3 catalysts only reportedCOx as the side-products.

Reaction kinetic studies further revealed that the consump-tion rate of alkane stabilized at higher oxygen partial pressures,resembling a Langmuir adsorption model. No catalytic activity inthe absence of oxygen was observed, and evidently oxygenadsorption on the h-BN surface was required for catalytic con-version of alkanes. The second order rate dependence on thealkane partial pressure were also verified. These kinetic char-acteristics suggested that oxygen species bound to the h-BNedge defects were responsible for the catalytic activity. More-over, the rate of n-butane consumption was higher than thoseobserved with isobutane at all tested partial pressures of alkaneand oxygen, indicating the lack of relationship between alkaneconsumption rate and the weakest C–H bond strength of eachalkane. The calculated apparent activation energies for n-butaneand isobutane ODH were higher than those of reported metaloxide catalysts.11

Spectroscopic characterization showed that B–OH and B–Ospecies were generated on the surface of h-BN after 48 hourson-stream in both n-butane and isobutane ODH. The signifi-cant decrease of surface nitrogen after the reaction suggestedthat oxygen may partially substitute nitrogen along the h-BNedges. Based on the above results, the author proposed a plausiblehypothesis (Fig. 7) for the formation of C4 olefins from a feed of

Fig. 5 The proposed redox reaction cycle in the oxidative dehydrogenation of propane over boron nitride. Reprinted from ref. 16 with permission.

Fig. 6 (A) Temperature gradients of VOx/g-Al2O3 and h-BN catalyst bedswith different tube diameters at the same GHSV in the ODH reaction ofpropane. (B) 3D temperature profile of a VOx/g-Al2O3 catalyst bed with6 mm reactor diameters; (C) 3D temperature profile of an h-BN catalystbed with 6 mm reactor diameters. (D) The temperature profiles of theVOx/g-Al2O3 catalyst bed with 60 mm reactor diameters. The unit oftemperature is 1C. Reprinted from ref. 98 with permission.

Fig. 7 Proposed catalytic cycle for the ODH reaction of light alkanes. Forpropane ODH: R = CH3, R0 = H, R00 = H. For isobutane ODH: R = CH3, R0 =CH3, R00 = H. Atom colors: boron = green, nitrogen = silver. Reprinted fromref. 11 with permission.

ChemComm Feature Article

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

This journal is©The Royal Society of Chemistry 2018 Chem. Commun., 2018, 54, 10936--10946 | 10943

oxygen and n-butane or isobutane.11 The catalytic active sitewas composed of associatively-adsorbed oxygen on an h-BNarmchair edge (step A). During the ODH reaction, the weakestC–H bond was abstracted by the electron-rich oxygen, breakingthe O–O bond (step B, C). In a rapid radical rebound mecha-nism, the nitroxyl species stabilized the butyl radical by form-ing a butoxyl intermediate (step D). The second hydrogenabstraction can occur from either primary or secondary carbonatoms. This abstraction was carried out by an adsorbed oxygenmolecule on a neighboring armchair site (step E). Similar tothe first hydrogen abstraction, a radical rebound mechanismstabilized the newly-formed radical. This process led to adoubly-bonded butylene intermediate (step F). Such a stabili-zation was likely to avoid the formation of free radicals that canpropagate in an autoxidation cycle. Finally, the olefin productdesorbed and the abstracted hydrogen atoms reorganized toform water (step G). Gas phase oxygen adsorption led to waterdesorption and subsequent active site regeneration along theh-BN edge.

3.3 Oxidative dehydrogenation of ethane

Boron nitride is featured by the excellent structural and thermalstability under oxidative atmospheres. Recently, our studiesshowed that boron nitrides were active catalysts for an ethaneODH reaction, typically operating at higher temperatures thanthose of propane and butane.15,17 In our studies, the BNOHcatalyst afforded surprisingly high selectivity and yield towardethylene.15 For example, the selectivity to ethylene was as highas 95% at 11% ethane conversion; at B40% conversion ofethane, the selectivity of ethylene still remains at 90%, superiorto that over most metal and metal oxide catalysts. At a very highconversion level of 63%, the ethylene selectivity remained at80%, corresponding to an ethylene yield of B50%, and only anegligible amount of CO2 (Fig. 8A). These performance data arecomparable to that of the industrialized ethane steam crackingprocess in view of the B85% selectivity to ethylene at B60% con-version of ethane, but much superior considering the much lowerreaction temperature and CO2 emission. The BNOH catalyst also

can afford high ethylene productivity, 9.1 gC2H4gcat�1 h�1, with

490% selectivity by mediating the reaction conditions (Fig. 8B).Such productivity far exceeds the critical value, 1 gC2H4

gcat�1 h�1,

which would be commercially attractive. The remarkable stabilityof the BNOH catalyst in the ODH of ethane was evidenced by theoperation for 200 hours at 590 1C (Fig. 8C), demonstrating itspotential for industrial application.

The dynamic evolution of B–OH groups under the ethaneODH reaction conditions was tracked using in situ FT-IRspectroscopy, identifying that the B–OH groups interacted withmolecular oxygen and incorporated into the reaction system.Isotope-labelling experiments further verified the dynamicexchange between the H atoms in ethane and the edge of theBNOH catalyst and the B–OH groups as the active sites. Kineticanalysis showed near half-order dependence on molecularoxygen and second-order dependence on ethane. The increasein selectivity with increasing oxygen concentration reveals thatmolecular oxygen favors the formation of ethylene. The apparentactivation energy of ethane was estimated to be 241.7 kJ mol�1.These kinetic behaviors are intrinsically different from traditionalmetal oxide catalysts which typically follow the Mars–Van Krevelenmechanism.15

Further report from Huang et al. showed that high surfacearea boron nitride nanosheets not only enable oxidative dehydro-genation of ethane exclusively to ethylene at near 10% conversion,but also delivered a remarkable 60% selectivity at an ethaneconversion of 78% and remained stable over 400 hours at575 1C.17 The characterization of the catalyst before and afterthe long-term run by microscopy and spectroscopy techniquesconfirmed that the B–O species emerges in the used catalyst.Operando Diffuse Reflectance Infrared Fourier-Transform(DRIFT) spectroscopy and electron paramagnetic spectroscopy(EPR) revealed that in the presence of ethane gas the surface ofthe BN catalyst was reduced, and the adjacent nitrogen canstabilize the ethyl radical (Fig. 9A). However, neither ethaneconversion nor ethylene product was observed under anaerobicconditions. Molecular oxygen was indispensable for a completeC–H dissociation, and finally responsible for the ethylenegeneration. The 18O isotope tracer further verified that thedipolar B–N edges did not directly activate molecular oxygen,but only proceeded via the aid of ethane (Fig. 9B).

Altogether, the authors draw two possible catalytic path-ways: at a kinetic measuring region, the ethane promoted theformation of B–OH active sites, thereby facilitating a nearlydirect dehydrogenation of ethane with the aid of O2 adsorptionto produce ethylene and hydrogen; at a non-kinetic measuringregion, it cannot be ruled out that B–O active sites are formedfrom the adsorbed O2, which were capable of abstracting hydro-gen from ethane to C2H4 and H2O. They therefore proposed thatthe presence of ethane promoted the activation of adsorbed O2

at the edges of BN and the formation of B–O(H) sites, and thedehydrogenation cycle was finally completed over B–O sites.The authors finally point out that the detailed comparisonbetween the role of B–O and B–OH groups in the alkane ODHreaction was still of value for deeply understanding the reactionmechanism.

Fig. 8 (A) Dependence of ethane conversion, ethylene selectivity andyield on the reaction temperature. (B) Effect of space velocity and reactiontemperature on the productivity of ethylene. (C) Long-term stability test at590 1C. Reprinted from ref. 15 with permission.

Feature Article ChemComm

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

10944 | Chem. Commun., 2018, 54, 10936--10946 This journal is©The Royal Society of Chemistry 2018

The follow-up study from Zhou et al. exhibited that there wasan induction period for the activity evolution on commercialh-BN for the ODH of ethane to ethylene.99 Various character-ization methods such as infrared spectroscopy, O2 adsorptionmicrocalorimetry, and transient analysis of products by massspectroscopy demonstrated the formation of hydroxyl specieson BN, i.e., B–OH species, in the induction period during theODH process. The presence of larger amounts of these specieson the activated BN can linearly increase the reaction rate ofethane conversion. It was suggested that B–OH species facili-tated the adsorption of O2 and then were transformed to B–Ospecies, which reacted with ethane to produce ethylene with theassistance of O2, thus resulting in a higher conversion rate ofethane. These findings nicely agree with our viewpoints on thecatalytic origin of boron nitride in the ODH reaction.16

3.4 Oxidative transformation of other alkanes

Beyond the ODH reaction of light alkanes, boron nitride wasfound to be active for the oxidative conversion of methane, amost important component in natural gas, to valuable chemicalswith minor formation of CO2 as well.12,100 In an open patent,Hermans et al. reveal that the use of h-BN can catalyse theoxidative coupling of methane to ethane and ethylene.12 Undertypical conditions (temperature, 770 1C; total flow, 80 mL min�1;PCH4

0.4 atm, PO20.2 atm, balance N2), h-BN exhibited a methane

conversion of 20.1% when compared to the activity (9.0%)observed with the quartz chips. The selectivity of C2 productsover h-BN is 37.9%, lower than that (47.7%) of the quartz chips,but the selectivity of carbon monoxide was close to 60%.12 In ourdetailed study, the conversion of methane was retained at B20%at 690 1C. The products include CO (76%), H2 (13%), C2H4 (10%),C2H6 (10%), and CO2 (4%). We have confirmed that the oxygen-containing function groups on the h-BN surface are decisive forits unique catalytic function in methane oxidation.100

In addition, carbon-doped boron nitride nanosheets alsoshowed high activity and selectivity in oxidative dehydrogenationof ethylbenzene to styrene as well as excellent oxidation resis-tance. In the study of Xie and Wang et al., the ethylbenzeneconversion reached B50% after a 9 h induction period using theporous BCN nanosheets as the ODH catalyst, and the styreneselectivity stably approached 89% and the main by-products werebenzene and toluene.101 Meanwhile, Ding and Lv reported that aBCN nanosheet could catalyse ethylbenzene dehydrogenation ina CO2 atmosphere, with B8% conversion and 495% selectivitytowards styrene at 550 1C.102 Their study further confirmed thatthe B–O species of the BCN nanosheet play a dominant rolecompared with surface carbon species in a CO2 atmosphere. Theethylbenzene could be attached onto the surface of the BCNnanosheets via the B–O–C bond, and the surface B–O groups thatwere regenerated by CO2 could act as the active sites.

4. Conclusions and futureperspectives

An ODH catalyst, functionalized boron nitride, was discoveredrecently, and features superior selectivity toward light olefinsand atom economy for valuable carbon-based products byminimizing CO2 emission. Boron nitride is also highly promis-ing for industrial implementation because of its high produc-tivity of light olefins, remarkable catalyst stability, superioranti-oxidation ability, and excellent thermal conductivity. Theoxygen-containing boron species on the surface of boronnitride are the active sites to trigger the ODH reaction of lightalkanes. Although there are different understandings of thecatalytic nature of boron nitride, it is universally acknowledgedthat oxygen-containing boron sites, gas-phase oxygen, andalkane molecules synergistically participate in the catalytic cycle.A newly proposed redox reaction cycle based on B–OH sites thatinitially react with molecular oxygen, leading to B–O–O–B inter-mediates (oxidation step), and the B–O–O–B species furtherabstracting the hydrogen atoms from alkane, forming olefinand water (reduction step), and then recovering to B–OH siteswith the assistance of water, can meet most experimental factsreported by different research groups.

This newly developed catalyst system not only opens up aresearch direction of metal-free catalysts in selective cleavageof C–H bonds of alkanes, but also enriches our fundamentalunderstanding of such industrially important ODH processes.Nevertheless, from our understanding, there are certainly manyremaining issues that need to be addressed. For example,

Fig. 9 Operando DRIFT difference spectra (A) and the corresponding GCprofiles (B) at 550 1C under aerobic/anaerobic conditions. The flow gasswitched from Ar to C2H6/Ar (Step 1), O2/Ar (Step 2), C2H6/Ar (Step 3) andfinally to C2H6/O2 (Step 4). The vibrations at 2753 and 2774 cm�1 (blackarrows in enlarge) were assigned to the surface ethyl species. Reprintedfrom ref. 17 with permission.

ChemComm Feature Article

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

This journal is©The Royal Society of Chemistry 2018 Chem. Commun., 2018, 54, 10936--10946 | 10945

developing new structure-tuning methods for optimizing theODH performance of boron nitride materials. Our studies haverevealed that OH-containing boron sites on boron nitridesurfaces are decisive for its unique catalytic function in theODH reaction. Thus, maximizing the number of OH-containingboron sites may be the most effective option to improve thecatalytic activity of the ODH reaction. We should put moreeffort into the development of more precise boron nitridesynthesis and functionalization strategies, such as preparationsof low-dimensional and porous structures, and hydroxylationmodifications of BN surfaces. It should be pointed out thatminimizing the cleavage of C–C bonds over boron nitridecatalysts remains challenging under the ODH conditions. Thus,there is an urgent need to develop new surface-modifyingmethods to enhance the selectivity toward the targeted olefin.For example, we are attempting to block the breaking site ofthe C–C bond using nucleophilic hetero-atom dopants. Thesuperior olefin selectivity may be achieved by exploring variousmodification methods. For practical applications, the stabilityof boron species under high-temperature steam still needs tobe improved. Overall, from the viewpoints of activity, selectivityand stability, there is still large room to improve the catalyticefficacy of boron nitride in the ODH reaction.

Moreover, one needs to figure out the detailed ODH reactionmechanism of boron nitride materials. Although several groupshave contributed to this field by demonstrating the catalyticorigin of boron nitride in the ODH reaction, the spectrum ofevidence of key intermediates under the realistic reaction con-ditions is still lacking. Further studies are expected to involvetheoretical simulations and the capture of reaction intermediatesto disclose the reaction mechanism. Moreover, some points onstructure–performance correlation, such as the geometric andelectronic characters of boron centres, the transformations of theB–O and B–OH groups, and the roles of nitrogen species in thealkane ODH reactions, still need to be precisely determinedusing advanced microscopic and spectroscopic methods underoperando conditions.

Finally, functionalized boron nitride as a new metal-freecatalyst may also be of interest for other reactions. For example,boron nitride has been recently demonstrated to be active in thereactions of olefin hydrogenation,103 acetylene hydrochlorination,104

dibenzothiophene oxidation,105 nitroaldol reaction106 and oxidativedesulfurization.107 These new attempts encourage further researchon the applications of boron nitride in the field of heterogeneouscatalysis.

Conflicts of interest

There are no conflicts to declare.

Acknowledgements

This work was financially supported by the State Key Program ofthe National Natural Science Foundation of China (21733002)and Cheung Kong Scholars Programme of China (T2015036).

References1 A. Corma, F. V. Melo, L. Sauvanaud and F. Ortega, Catal. Today,

2005, 107–108, 699–706.2 J. Z. Li, Y. X. Wei, J. R. Chen, P. Tian, X. Su, S. T. Xu, Y. Qi,

Q. Y. Wang, Y. Zhou, Y. L. He and Z. M. Liu, J. Am. Chem. Soc., 2012,134, 836–839.

3 E. McFarland, Science, 2012, 338, 340–342.4 J. J. H. B. Sattler, J. Ruiz-Martinez, E. Santillan-Jimenez and B. M.

Weckhuysen, Chem. Rev., 2014, 114, 10613–10653.5 G. A. Olah and A. Molnar, Hydrocarbon Chemistry, Wiley, New York,

2nd edn, 2003, ch. 2, pp. 30–85.6 L. Shi, G.-M. Deng, W.-C. Li, S. Miao, Q.-N. Wang, W.-P. Zhang and

A.-H. Lu, Angew. Chem., Int. Ed., 2015, 54, 13994–13998.7 A. S. Bodke, D. A. Olschki, L. D. Schmidt and E. Ranzi, Science,

1999, 285, 712–715.8 R. Grabowski, Catal. Rev.: Sci. Eng., 2006, 48, 199–268.9 C. A. Carrero, R. Schloegl, I. E. Wachs and R. Schomaecker, ACS

Catal., 2014, 4, 3357–3380.10 J. T. Grant, M. C. A. Carrero, F. Goeltl, J. Venegas, P. Mueller, S. P.

Burt, S. E. Specht, W. P. McDermott, A. Chieregato and I. Hermans,Science, 2016, 354, 1570–1573.

11 J. M. Venegas, J. T. Grant, W. P. McDermott, S. P. Burt, J. Micka,M. C. A. Carrero and I. Hermans, ChemCatChem, 2017, 9, 2118–2127.

12 I. Hermans, J. T. Grant, M. C. A. Carrero, A. Chieregato and J. M.Venegas, US2017066700-A1, WO2017044711-A1, CA2997764-A1, 2017.

13 L. Shi, D. Wang, W. Song, D. Shao, W.-P. Zhang and A.-H. Lu,ChemCatChem, 2017, 9, 1788–1793.

14 A.-H. Lu, L. Shi and W.-C. Li, CN106694017-A, 2017.15 L. Shi, B. Yan, D. Shao, F. Jiang, D. Wang and A.-H. Lu, Chin.

J. Catal., 2017, 38, 389–395.16 L. Shi, D. Wang and A.-H. Lu, Chin. J. Catal., 2018, 39, 908–913.17 R. Huang, B. Zhang, J. Wang, K.-H. Wu, W. Shi, Y. Zhang, Y. Liu,

A. Zheng, R. Schloegl and D. S. Su, ChemCatChem, 2017, 9,3293–3297.

18 D. S. Su and R. Huang, CN106140240-A, 2016.19 A. S. Bodke, D. A. Olschki, L. D. Schmidt and E. Ranzi, Science,

1999, 285, 712–715.20 J. L. Lu, B. S. Fu, M. C. Kung, J. M. Xiao, J. W. Elam, H. H. Kung and

P. C. Stair, Science, 2012, 335, 1205–1208.21 X. Lin, K. R. Poeppelmeier and E. Weitz, Appl. Catal., A, 2010, 381,

114–120.22 H. B. Zhu, D. C. Rosenfeld, M. Harb, D. H. Anjum, M. N. Hedhili,

S. O. Chikh and J.-M. Basset, ACS Catal., 2016, 6, 2852–2866.23 B. Solsona, J. M. L. Nieto, S. Agouram, M. D. Soriano, A. Dejoz,

M. L. Vazquez and P. Concepcion, Top. Catal., 2016, 59, 1–9.24 R. Sanchis, D. Delgado, S. Agouram, M. D. Soriano, M. I. Vazquez,

E. Rodrıguez-Castellon, B. Solsona and J. M. Lopez Nieto, Appl.Catal., A, 2017, 536, 18–26.

25 E. Heracleous and A. A. Lemonidou, J. Catal., 2006, 237, 162–171.26 E. Heracleous and A. A. Lemonidou, J. Catal., 2006, 237, 175–186.27 Z. S. Chao and E. Ruckenstein, Catal. Lett., 2003, 88, 147–154.28 P. Botella, E. Garcıa-Gonzalez, A. Dejoz, J. M. Lopez Nieto, M. I.

Vazquez and J. Gonzalez-Calbet, J. Catal., 2004, 225, 428–438.29 Q. Xie, L. Chen, W. Weng and H. L. Wan, J. Mol. Catal. A: Chem.,

2005, 240, 191–196.30 E. V. Ishchenko, R. V. Gulyaev, T. Y. Kardash, A. V. Ishchenko,

E. Yu. Gerasimov, V. I. Sobolev and V. M. Bondareva, Appl. Catal., A,2017, 534, 58–69.

31 B. Sarkar, R. Goyal, L. N. S. Konathala, C. Pendem, T. Sasaki andR. Bal, Appl. Catal. B-Environ., 2017, 217, 637–649.

32 C. A. Gartner, A. C. V. Veen and J. A. Lercher, Top. Catal., 2014, 57,1236–1247.

33 H. X. Dai, C. F. Ng and C. T. Au, Catal. Lett., 1999, 57, 115–120.34 Q. J. Ge, B. Zhaorigetu, C. Y. Yu, W. Z. Li and H. Y. Xu, Catal. Lett.,

2000, 68, 59–62.35 Z. Q. Zhang, J. Ding, R. J. Chai, G. F. Zhao, Y. Liu and Y. Lu, Appl.

Catal., A, 2018, 550, 151–159.36 H. X. Dai, C. F. Ng and C. T. Au, J. Catal., 2000, 193, 65–79.37 H. X. Dai, C. F. Ng and C. T. Au, J. Catal., 2000, 189, 52–62.38 S. A. R. Mulla, O. V. Buyevskaya and M. Baerns, J. Catal., 2001, 197,

43–48.39 S. A. R. Mulla, O. V. Buyevskaya and M. Baerns, Appl. Catal., A,

2002, 226, 73–78.

Feature Article ChemComm

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online

10946 | Chem. Commun., 2018, 54, 10936--10946 This journal is©The Royal Society of Chemistry 2018

40 F. Cavani, N. Ballarini and A. Cericola, Catal. Today, 2007, 127,113–131.

41 https://www.uop.com/processing-solutions/petrochemicals/olefins/#propylene.

42 C. Carrero, M. Kauer, A. Dinse, T. Wolfram, N. Hamilton,A. Trunschke, R. Schlogl and R. Schomacker, Catal. Sci. Technol.,2014, 4, 786–794.

43 S. Vajda, M. J. Pellin, J. P. Greeley, C. L. Marshall, L. A. Curtiss,G. A. Ballentine, J. W. Elam, S. Catillon-Mucherie, P. C. Redfern,F. Mehmood and P. Zapol, Nat. Mater., 2009, 8, 213–216.

44 E. V. Kondratenko, O. V. Buyevskaya and M. Baerns, Top. Catal.,2001, 15, 175–180.

45 Y. M. Liu, W. L. Feng, T. C. Li, H. Y. He, W. L. Dai, W. Huang,Y. Cao and K. N. Fan, J. Catal., 2006, 239, 125–136.

46 B. Solsona, T. Blasco, J. M. L. Nieto, M. L. Pena, F. Rey and A. Vidal-Moya, J. Catal., 2001, 203, 443–452.

47 Q. Liu, J. Li, Z. Zhao, M. Gao, L. Kong, J. Liu and Y. Wei, Catal. Sci.Technol., 2016, 6, 5927–5941.

48 Y. Liu, C. Jiang, W. Chu, W. Sun and Z. Xie, React. Kinet., Mech.Catal., 2010, 101, 141–151.

49 A. A. Lemonidou, L. Nalbandian and I. A. Vasalos, Catal. Today,2000, 61, 333–341.

50 S. Chen, F. Ma, A. X. Xu, L. N. Wang, F. Chen and W. M. Lu, Appl.Surf. Sci., 2014, 289, 316–325.

51 L. Leveles, S. Fuchs, K. Seshan, J. A. Lercher and L. Lefferts, Appl.Catal., A, 2002, 227, 287–297.

52 L. Leveles, K. Seshan, J. A. Lercher and L. Lefferts, J. Catal., 2003,218, 296–306.

53 L. Leveles, K. Seshan, J. A. Lercher and L. Lefferts, J. Catal., 2003,218, 307–314.

54 C. Trionfetti, I. V. Babich, K. Seshan and L. Lefferts, Appl. Catal., A,2006, 310, 105–113.

55 R. B. Watson and U. S. Ozkan, J. Catal., 2000, 191, 12–29.56 M. D. Putra, S. M. Al-Zahrani and A. E. Abasaeed, Catal. Commun.,

2011, 14, 107–110.57 D. L. Stern and R. K. Grasselli, J. Catal., 1997, 167, 550–559.58 B. Farin, P. Eloy, C. Poleunis, M. Devillers and E. M. Gaigneaux,

Catal. Sci. Technol., 2016, 6, 6046–6056.59 J.-H. Li, C.-C. Wang, C.-J. Huang, Y.-F. Sun, W.-Z. Weng and H.-L.

Wan, Appl. Catal., A, 2010, 382, 99–105.60 Q. Zhang, C. Cao, T. Xu, M. Sun, J. Zhang, Y. Wang and H. Wan,

Chem. Commun., 2009, 2376–2378.61 J. Li, C. Wang, C. Huang, W. Weng and H. Wan, Catal. Lett., 2010,

137, 81–87.62 B. Y. Jibril, Appl. Catal., A, 2004, 264, 193–202.63 Y. M. Liu, W. L. Feng, L. C. Wang, Y. Cao, W. L. Dai, H. Y. He and

K. N. Fan, Catal. Lett., 2006, 106, 145–152.64 M. Andrea De Leon, C. De Los Santos, L. Latronica, A. Maria Cesio,

C. Volzone, J. Castiglioni and M. Sergio, Chem. Eng. J., 2014, 241,336–343.

65 V. C. Corberan, R. X. Valenzuela, B. Sulikowski, M. Derewinski,Z. Olejniczak and J. Krysciak, Catal. Today, 1996, 32, 193–204.

66 J. Zhang, M. Sun, C. Cao, Q. Zhang, Y. Wang and H. Wan, Appl.Catal., A, 2010, 380, 87–94.

67 M. Khachani, M. Kacimi, A. Ensuque, J.-Y. Piquemal, C. Connan,F. Bozon-Verduraz and M. Ziyad, Appl. Catal., A, 2010, 388,113–123.

68 R. You, X. Y. Zhang, L. F. Luo, Y. Pan, H. B. Pan, J. Z. Yang, L. H. Wu,X. S. Zheng, Y. K. Jin and W. X. Huang, J. Catal., 2017, 348, 189–199.

69 P. Michorczyk, P. Kustrowski, P. Niebrzydowska and A. Wach, Appl.Catal., A, 2012, 445, 321–328.

70 R. Goyal, B. Sarkar, A. Bag, F. Lefebvre, S. Sameer, C. Pendem andA. Bordoloi, J. Mater. Chem. A, 2016, 4, 18559–18569.

71 X. Sun, Y. Ding, B. Zhang, R. Huang, D. Chen and D. S. Su, ACSCatal., 2015, 5, 2436–2444.

72 P. J. Chenier, Survey of Industrial Chemistry, Kluwer Academic/Plenum Publishers, New York, 3rd edn, 2002.

73 B. Grzybowska, J. Sloczynski, R. Grabowski, K. Wcislo, A. Kozlowska,J. Stoch and J. Zielinskiy, J. Catal., 1998, 178, 687–700.

74 J. G. Deng, L. Zhang, C. X. Liu and Y. S. Dai, Catal. Today, 2011,164, 347–352.

75 M. Hoang, J. F. Mathews and K. C. Pratt, React. Kinet. Catal. Lett.,1997, 61, 21–26.

76 L. He, L. Fu and Y. Z. Tang, Catal. Sci. Technol., 2015, 5, 1115–1125.77 F. Cavani, C. Comuzzi, G. Dolcetti, E. Etienne, R. G. Finke,

G. Selleri, F. Triffro and A. Trovarelli, J. Catal., 1996, 160, 317–321.78 B. Sulikowski, Z. Olejniczak, E. Włoch, J. Rakoczy, R. X. Valenzuela

and V. Cortes Corberan, Appl. Catal., A, 2002, 232, 189–202.79 J. Q. Guan, H. Y. Xu, K. Song, B. Liu, F. P. Shang, X. F. Yu and

Q. B. Kan, Catal. Lett., 2008, 126, 293–300.80 A. Kaddouri, C. Mazzocchia and E. Tempesti, Appl. Catal., A, 1998,

169, L3–L7.81 Y. S. K. Takita, Q. Xia, A. Takami, H. Nishihuchi and K. Nagaoka,

Appl. Catal., A, 2005, 296, 63–69.82 S. M. Al-Zahrani, N. O. Elbashir, A. E. Abasaeed and M. Abdulwahed,

Catal. Lett., 2000, 69, 65–70.83 H. A. Almukhlifi and R. C. Burns, J. Mol. Catal. A: Chem., 2015, 408,

26–40.84 J. J. D. Velasquez, L. M. C. Suarez and J. L. Figueiredo, Appl. Catal.,

A, 2006, 311, 51–57.85 I. Gniot, P. Kirszensztejn and M. Kozłowski, Appl. Catal., A, 2009,

362, 67–74.86 H. Xie, Z. Wu, S. H. Overbury, C. Liang and V. Schwartz, J. Catal.,

2009, 267, 158–166.87 J. Zhang, X. Liu, R. Blume, A. Zhang, R. Schlogl and D. S. Su,

Science, 2008, 322, 73–77.88 A. Pakdel, Y. Bando and D. Golberg, Chem. Soc. Rev., 2014, 43,

934–959.89 Q. Weng, X. Wang, X. Wang, Y. Bando and D. Golberg, Chem. Soc.

Rev., 2016, 45, 3989–4012.90 Y. Wang, L. Shi, W. Lu, Q. Sun, Z. Wang, C. Zhi and A.-H. Lu,

ChemCatChem, 2017, 9, 1363–1367.91 T. W. Hansen, J. B. Wagner, P. L. Hansen, S. Dahl, H. Topsoe and

C. J. H. Jacobsen, Science, 2001, 294, 1508–1510.92 Y. Zhang, X. Weng, H. Li, H. Li, M. Wei, J. Xiao, Z. Liu, M. Chen,

Q. Fu and X. Bao, Nano Lett., 2015, 15, 3616–3623.93 L. Gao, Q. Fu, M. Wei, Y. Zhu, Q. Liu, E. Crumlin, Z. Liu and X. Bao,

ACS Catal., 2016, 6, 6814–6822.94 P. Kube, B. Frank, R. Schlogl and A. Trunschke, ChemCatChem,

2017, 9, 3446–3455.95 Q. L. Liu, J. M. Li, Z. Zhao, M. L. Gao, L. Kong, J. Liu and Y. C. Wei,

Catal. Sci. Technol., 2016, 6, 5927–5941.96 J. T. Grant, W. P. McDermott, J. M. Venegas, S. P. Burt, J. Micka,

S. P. Phivilay, C. A. Carrero and I. Hermans, ChemCatChem, 2017, 9,3623–3626.

97 P. Chaturbedy, M. Ahamed and M. Eswaramoorthy, ACS Omega,2018, 3, 369–374.

98 J. S. Tian, J. H. Lin, M. L. Xu, S. L. Wan, J. D. Lin and Y. Wang,Chem. Eng. Sci., 2018, 186, 142–151.

99 Y. L. Zhou, J. Lin, L. Li, X. L. Pan, X. C. Su and X. D. Wang, J. Catal.,2018, 365, 14–23.

100 Y. Wang, L. Y. Zhao, L. Shi, J. Sheng, W. P. Zhang, X.-M. Cao,P. J. Hu and A.-H. Lu, Catal. Sci. Technol., 2018, 8, 2051–2055.

101 F. Guo, P. Yang, Z. Pan, X.-N. Gao, Z. Xie and X. Wang, Angew.Chem., Int. Ed., 2017, 56, 8231–8235.

102 L. C. Wang, C. H. Wang, Z. W. Zhang, J. H. Wu, R. M. Ding andB. L. Lv, Appl. Surf. Sci., 2017, 422, 574–581.

103 D. J. Nash, D. T. Restrepo, N. S. Parra, K. E. Giesler, R. A. Penabade,M. Aminpour, D. Le, Z. Y. Li, O. K. Farha, J. K. Harper,T. S. Rahman and R. G. Blair, ACS Omega, 2016, 1, 1343–1354.

104 P. Li, H. B. Li, X. Pan, K. Tie, T. T. Cui, M. Z. Ding and X. H. Bao,ACS Catal., 2017, 7, 8572–8577.

105 P. W. Wu, S. Z. Yang, W. S. Zhu, H. P. Li, Y. H. Chao, H. Y. Zhu,H. M. Li and S. Dai, Small, 2017, 13, 1701857.

106 S. Torii, K. Jimura, S. Hayashi, R. Kikuchi and A. Takagaki, J. Catal.,2017, 355, 176–184.

107 Y. C. Wu, P. W. Wu, Y. H. Chao, J. He, H. P. Li, L. J. Lu, W. Jiang, B. B.Zhang, H. M. Li and W. S. Zhu, Nanotechnology, 2018, 29, 025604.

ChemComm Feature Article

Publ

ishe

d on

14

Aug

ust 2

018.

Dow

nloa

ded

by D

alia

n U

nive

rsity

of

Tec

hnol

ogy

on 6

/27/

2019

9:4

5:29

AM

. View Article Online