Special Lectures on Environmental Science IIpcat.cat.hokudai.ac.jp › class › ees_2011 ›...

2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 1

environmental application of photocatalysisenvironmental application of photocatalysis

Special Lectures on Environmental Science IISpecial Lectures on Environmental Science II

introductionintroductionchemistry and catalysis for lowchemistry and catalysis for low--carbon societycarbon societyenvironmental application of photocatalysisenvironmental application of photocatalysis

examples of practical applicationsexamples of practical applicationsrecent research topicsrecent research topics

Bunsho OHTANI, ProfessorBunsho OHTANI, ProfessorCatalysis Research Center/Graduate School of Environmental ScienCatalysis Research Center/Graduate School of Environmental ScienceceHokkaido UniversityHokkaido [email protected]@cat.hokudai.ac.jp Ohtani Lab Hokkaido searchsearch


photocatalysis: two major phenomena

photocatalytic decompositiontarget:

organic compoundssteins (oil)microorganisms

photocatalytic decompositiontarget:

organic compoundssteins (oil)microorganisms

photoinduced (super) hydrophilicitywashable with running wateranti-fogging

photoinduced (super) hydrophilicitywashable with running wateranti-fogging

mechanismmechanism


regular PVCregular PVC TeflonTeflon--coatedcoated titaniatitania--coatedcoated

after exposure outdoor for 5 monthsafter exposure outdoor for 5 months

showing showing change in change in

colorcolor

Taiyo KogyoTaiyo Kogyohttp://http://www.taiyokogyo.co.jpwww.taiyokogyo.co.jp//

tent material coated with titania photocatalysttent material coated with titania photocatalyst

PVC must contain PVC must contain organic additives, which organic additives, which go out to the surface go out to the surface slowly, to be elastic.slowly, to be elastic.


titaniatitania--coated glass of our buildingcoated glass of our building

•• all glass plates are coated with titania to reduce all glass plates are coated with titania to reduce infraredinfrared radiationradiation (with (with expectation to keep the surfaces clean).expectation to keep the surfaces clean).

•• coated on site; not construction with precoated on site; not construction with pre--coated glass platescoated glass plates•• expected photocatalytic selfexpected photocatalytic self--cleaning effectcleaning effect


substrate: steal plates

JFE Building Materialshttp://www.jfe-kenzai.co.jp/index.shtml

exterior materials coated with titania


withwith

paints requiring paints requiring no heatingno heating: room: room--temperature coatingtemperature coating

titania photocatalytic paintingtitania photocatalytic painting

painting procedure with brush or rollerpainting procedure with brush or roller

painting procedure:painting procedure:sprayingspraying

withoutwithoutwithwith

withoutwithout

withwith withoutwithout


largelarge--scale application of photocatalystsscale application of photocatalysts

"self"self--cleaning" window glassescleaning" window glasses

"Marubiru", a large office building in Tokyo

"Centrea", Chubu International airport, Nagoya


insideinside: : antianti--fogging effect to give water dropletfogging effect to give water droplet--free surfacefree surfaceoutsideoutside: : photocatalytic decomposition and (super) hydrophilicity to photocatalytic decomposition and (super) hydrophilicity to

keep the surface clean keep the surface clean

photocatalyst coated glassphotocatalyst coated glass

Japan Hydrotect CoatingsJapan Hydrotect Coatings

regular regular glassglass

titaniatitania--coated coated glassglass

onon--site coating > presite coating > pre--coatingcoating


Nippon SodaNippon Sodahttp://www.nipponhttp://www.nippon--soda.co.jp/photo/report.htmlsoda.co.jp/photo/report.html

titania coatings with heating = pretitania coatings with heating = pre--coating window blindscoating window blinds

titania photocatalysttitania photocatalyst--including paintincluding paint

No effect of photoNo effect of photo--induced hydrophilicity is induced hydrophilicity is expected for indoor use.expected for indoor use.


"partition" with photocatalytic coatings"partition" with photocatalytic coatings

possible effects:possible effects:cleaning by decomposition of organic matters/deodorization/anticleaning by decomposition of organic matters/deodorization/anti--microorganismsmicroorganisms

Mitsubishi Plasticshttp://www.mpi.co.jp/press/pr030501.htm


titaniatitania--coatings for anticoatings for anti--foggingfogging

TOTOTOTO

regularregularpartpart

titaniatitaniacoatedcoatedpartpart

no water droplets due to the (super) hydrophilicity of photocatano water droplets due to the (super) hydrophilicity of photocatalytic lytic titania surfacetitania surface


polycarbonate plates covered withpolycarbonate plates covered withtitania photocatalyst on both sidestitania photocatalyst on both sides

Sekisui PlasticsSekisui Plasticshttp://http://www.sekisuijushi.co.jpwww.sekisuijushi.co.jp//

roadroad--side sound barriers coated with titaniaside sound barriers coated with titania

titaniatitania1.5 year1.5 year

regularregular1.5 year1.5 year

regularregular3.5 year3.5 year


pavements containing titania photocatalystpavements containing titania photocatalyst

""PhotoroadPhotoroad""

Nitrogen oxides (NONitrogen oxides (NOxx)) are oxidized by photocatalystare oxidized by photocatalystResulting Resulting nitrate (NOnitrate (NO33

--)) ions are captured by calcium ionsions are captured by calcium ionsCalcium nitrate (Ca(NOCalcium nitrate (Ca(NO33))22)) is washed out by rain wateris washed out by rain water

FujitaFujitahttp://http://www.fujita.co.jpwww.fujita.co.jp


Toshiba Toshiba LightecLightechttp://http://www.tlt.co.jp/tlt/new/crean/crean.htmwww.tlt.co.jp/tlt/new/crean/crean.htm

a covering window glass coated with a covering window glass coated with titaniatitania

lights for lights for outdoor useoutdoor use

regularregularfluorescent lampfluorescent lamp

lighting device with titania photocatalystlighting device with titania photocatalyst


photocatalytic air purifier unitphotocatalytic air purifier unit

active air purification: active air purification: decontamination and deodorization of circulating airdecontamination and deodorization of circulating air

Hitachi Home and Life SolutionHitachi Home and Life Solutionhttp://www.hitachihttp://www.hitachi--hl.com/hl.com/

Daikin Ltd.Daikin Ltd.http://http://www.daikinaircon.comwww.daikinaircon.com//

air conditionerair conditionerair conditioner

air purifierair purifierair purifier


photocatalytic treatment of waterphotocatalytic treatment of water

Sumitomo Metal IndustriesSumitomo Metal Industrieshttp://www.sumitomometals.co.jp/news/monthly/2001/140.htmlhttp://www.sumitomometals.co.jp/news/monthly/2001/140.html

polluted polluted gasgas

draindrain

aeration unitaeration unit

waterwater

exhaustexhaust

pumppump

soilsoil

groundgroundwaterwater

airair

dryerdryerseparatorseparator photocataphotocata--lystlyst

neutraneutra--lizerlizer

decontaminateddecontaminated

polluted gaspolluted gasblack lightblack light

flowflow apparatusapparatus

Contaminated ground water is treated to remove volatile organic Contaminated ground water is treated to remove volatile organic compounds.compounds.


smoke cleaner/refrigeratorsmoke cleaner/refrigerator

Toshiba/Mitsubishihttp://www.toshiba.co.jp/about/press/2001_09/pr_j0302.htmhttp://www.mitsubishielectric.co.jp/news/2009/0825-a.htm

Toshiba/MitsubishiToshiba/Mitsubishihttp://www.toshiba.co.jp/about/press/2001_09/pr_j0302.htmhttp://www.toshiba.co.jp/about/press/2001_09/pr_j0302.htmhttp://www.mitsubishielectric.co.jp/news/2009/0825http://www.mitsubishielectric.co.jp/news/2009/0825--a.htma.htm

deodorization/decomposition of ethylene (CHdeodorization/decomposition of ethylene (CH22=CH=CH22) from ) from vegetables/fruits to keep freshnessvegetables/fruits to keep freshness


photocatalytic water treatmentphotocatalytic water treatment

photocatalytic fiber cartridge for decomposition of dioxin and sphotocatalytic fiber cartridge for decomposition of dioxin and sterilizationterilization

UBE Industrieshttp://www.ube-ind.co.jp/japanese/japanese/annai/01_05_03.htm

チタニアが有機物を酸化分解する光触媒機能に着目して、接触面積が大きく、丈夫な繊維状にしたのが『光触媒繊維』。既存の光触媒製品と差別化した製品の特色を活かして市場開発を進めています。この新素材はダイオキシンの分解にも期待されています。

チタニアが有機物を酸化分解する光触媒機能に着目して、接触面積が大きく、丈夫な繊維状にしたのが『光触媒繊維』。既存の光触媒製品と差別化した製品の特色を活かして市場開発を進めています。この新素材はダイオキシンの分解にも期待されています。


a TOC analyzer with a photocatalytic reactora TOC analyzer with a photocatalytic reactor

Hiranuma Industrieshttp://www.hiranuma.com/products/envr/toc/

Hiranuma Industrieshttp://www.hiranuma.com/products/envr/toc/

•• Analyzing TOC (total organic carbon), organic compounds are decoAnalyzing TOC (total organic carbon), organic compounds are decomposed by oxidants mposed by oxidants into carbon dioxide (COinto carbon dioxide (CO22) and the amount of CO) and the amount of CO22 is measured.is measured.

•• Conventional analyzers require the use of potassium permanganateConventional analyzers require the use of potassium permanganate as an oxidant or of as an oxidant or of a expensive shorta expensive short--wavelength (254 nm) mercury arc lamp.wavelength (254 nm) mercury arc lamp.

•• Using a titanium(IV) oxide photocatalyst system, any chemicals Using a titanium(IV) oxide photocatalyst system, any chemicals and their post and their post treatment are not needed and cheaper longtreatment are not needed and cheaper long--wavelength mercury arc lamps can be wavelength mercury arc lamps can be used.used.

TOC-3000TOCTOC--30003000

TOC-2000TOCTOC--20002000


photocatalysis industries in Japanphotocatalysis industries in Japanindustries related to photocatalysisindustries related to photocatalysisalmost 300 million USD after 2005almost 300 million USD after 2005(Photocatalysis Industry Association of Japan)(Photocatalysis Industry Association of Japan)

othersotherslivingwarelivingwarecleanupcleanuproadroadinteriorinteriorexteriorexteriorm

illio

n U

SD

mill

ion

US

D

400400

300300

200200

100100

0020002000 20022002 20042004 20062006 20082008


photocatalysis industries in Japanphotocatalysis industries in Japan

2008 (2007): ca. 320 million USD2008 (2007): ca. 320 million USD

othersothers

exteriorexterior

interiorinterior

roadroad

cleanupcleanup

livingwarelivingware


photocatalysis: two major phenomenaphotocatalysis: two major phenomena

superhydrophilicity: superhydrophilicity: the surface of the surface of photocatalytic (titania) coatings photocatalytic (titania) coatings becomes super hydrophilic, i.e., becomes super hydrophilic, i.e., contact angle to be almost zero. contact angle to be almost zero.

photocatalytic oxidation: photocatalytic oxidation: organic and organic and inorganic compounds are oxidized under inorganic compounds are oxidized under air to be inorganic materials, i.e, air to be inorganic materials, i.e, mineralization.mineralization.

left: photocatalytic/right: ordinaryleft: photocatalytic/right: ordinaryleft: photocatalytic/right: ordinary

mechanismmechanism

光触媒014 2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 23

in general, titanium compounds are hydrolyzed to titanic acid in general, titanium compounds are hydrolyzed to titanic acid and then calcined to dehydrate and crystallize into titaniaand then calcined to dehydrate and crystallize into titania

at higher calcination temperatureat higher calcination temperaturesmaller specific surface areasmaller specific surface areahigher crystallinity = smaller defectshigher crystallinity = smaller defects

liquidliquid--phase syntheses of titania photocatalystphase syntheses of titania photocatalyst

Ti(OR)Ti(OR)44alkoxidealkoxide

TiXTiX44halidehalide

Ti(SOTi(SO44))22sulfatesulfate

Ti(OH)Ti(OH)44・・TiO(OH)TiO(OH)22hydrated titania/titanium hydroxidehydrated titania/titanium hydroxide

amorphous titaniaamorphous titania

TiOTiO22titaniatitania

hydrolysishydrolysis calcinationcalcination

dehydration/dehydration/crystallizationcrystallization


preparation of highly active photocatalystpreparation of highly active photocatalyst

HyCOMHyCOMHyHydrothermal drothermal CCrystallization in rystallization in OOrganic rganic MMediaediasimultaneous hydrolysis and simultaneous hydrolysis and crystallization by small amount of crystallization by small amount of water dissolved in organic solvent water dissolved in organic solvent under pressureunder pressure

TDTDTThermal hermal DDecompositionecompositionthermal decomposition of alkoxidethermal decomposition of alkoxide

THyCATHyCATTransfer ransfer HyHydrolytic drolytic CCrystallization rystallization with with AAlcoholslcoholssimultaneous hydrolysis and simultaneous hydrolysis and crystallization of alkoxide by water crystallization of alkoxide by water liberated by thermal decomposition of liberated by thermal decomposition of alcoholsalcohols

furnacefurnace

autoclaveautoclave

glass tubeglass tube

alkoxidealkoxide/solvent/solvent

waterwater(HyCOM)(HyCOM)


a

examples of highly active titania particlesexamples of highly active titania particles

titania particles synthesized by HyCOM methodtitania particles synthesized by HyCOM methodfringes corresponding to anatase lattice / nanosized single crysfringes corresponding to anatase lattice / nanosized single crystaltalCatal. TodayCatal. Today, , 8484, 181, 181--189 (2003)189 (2003)

titania particles synthesized by THyCA methodtitania particles synthesized by THyCA methodEach crystallites are edgeEach crystallites are edge--shaped single crystal of anatase.shaped single crystal of anatase.

5 nm

50 nm


natural crystal of anatase titanianatural crystal of anatase titania

square bipyramid exposing {101} facetssquare bipyramid exposing {101} facets

fujikura001 2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 27

gasgas--phase reaction of phase reaction of titanium(IV) chloridetitanium(IV) chloride

[collaboration work with [collaboration work with Fujikura and Showa Fujikura and Showa Titanium]Titanium]

particle size: 40particle size: 40--150 nm150 nmsurface area: 10surface area: 10--40 m40 m22 gg--11

highly crystallizedhighly crystallizedexposing {101} and {001}exposing {101} and {001}low density of defectslow density of defects

(001)(001)

(101)(101)

decahedral anatase titania particlesdecahedral anatase titania particles


use of infrared furnace to heat up only the use of infrared furnace to heat up only the part covered with platinum ribbon = part covered with platinum ribbon = rapid rapid heating and rapid coolingheating and rapid cooling

oil bathoil bath393 K393 K

ArAr

TiClTiCl44

OO22

to make efficient heatingto make efficient heating

bufflebuffle

vaporizervaporizerPt platePt plate

4 cm width/1473 K4 cm width/1473 K

100 nm100 nm100 nm

gasgas--phase synthesis of decahedral particlesphase synthesis of decahedral particles

fujikura002 2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 29

higher photocatalytic activityhigher photocatalytic activity

relatively high photocatalytic activity even though not so relatively high photocatalytic activity even though not so large specific surface arealarge specific surface area

effective also foreffective also for

CHCH33OH = HCHO + HOH = HCHO + H22

2CH2CH33CHO + 5OCHO + 5O22

= 4CO= 4CO22 + 4H+ 4H22O O

methanol methanol dehydrogenationdehydrogenation

acetaldehyde acetaldehyde decompositiondecomposition


titanium(IV) oxide and tungsten(VI) oxidetitanium(IV) oxide and tungsten(VI) oxide

ultravioletultraviolet visiblevisible

TiOTiO22

fluorescent fluorescent lightlight

WOWO33

Wavelength/nmWavelength/nm500500450450400400350350300300

Why WOWhy WO33 has has notnot been used?been used?


STEM images of Pt(1wt%)STEM images of Pt(1wt%)--loaded WOloaded WO33

highly uniform dispersion of platinum particles (average size: 5highly uniform dispersion of platinum particles (average size: 5 nm) on WOnm) on WO33

20 nm20 nm


photocatalytic activity test (liquid phase)photocatalytic activity test (liquid phase)

test reaction: decomposition of acetic acidtest reaction: decomposition of acetic acid

CHCH33COOH + 2OCOOH + 2O22 →→ 22COCO22 + 2H+ 2H22OO

photocatalyst: 50 mgphotocatalyst: 50 mgaqueous acetic acid solutionaqueous acetic acid solution

(5 vol%, 250 mL)(5 vol%, 250 mL)300300--W xenon lampW xenon lampFFull arc irradiation:ull arc irradiation:

300 < l < 500 nm300 < l < 500 nmWith LWith L--42 cutoff filter:42 cutoff filter:

400 < l < 500 nm400 < l < 500 nmGas phase analysis: onGas phase analysis: on--line GCline GC


200

150

100

50

02520151050

2000

1500

1000

500

0121086420

ca. 190 ca. 190 µµmol hmol h--1 1 ca. 7 ca. 7 µµmol hmol h--1 1

time/htime/h time/htime/h

amou

nt o

f CO

amou

nt o

f CO

22// µµm

ol

mol

COCO22 generation under visible light (> 400 nm)generation under visible light (> 400 nm)

Bare WOBare WO3 3 Pt(0.5 wt%)Pt(0.5 wt%)--WOWO3 3

rate of COrate of CO22 generation increased remarkably with Pt loadinggeneration increased remarkably with Pt loading(up to a maximum of 230 (up to a maximum of 230 µµmol hmol h--11 at 1 wt% of Pt loading) at 1 wt% of Pt loading)

amou

nt o

f CO

amou

nt o

f CO

22// µµm

ol

mol


comparison with TiOcomparison with TiO22 (P25) photocatalyst(P25) photocatalyst

800

600

400

200

02101801501209060300

Pt-WO3 full arc Pt-WO3 vis TiO2 P25 full arc TiO2 P25 vis

irradiation time/minirradiation time/min

amou

nt o

f CO

amou

nt o

f CO

22// mmm

olm

ol

UV + Vis. (300 < UV + Vis. (300 < ll < 500)< 500)

Vis. (400 < Vis. (400 < ll < 500)< 500)

Pt(1 wt%)Pt(1 wt%)--WOWO33 vs. vs. TiOTiO22 (P25)(P25)


test reaction: decomposition of acetaldehydeCH3CHO + 5/2 O2 → 2CO2 + 2H2O

photocatalyst: 50 mgacetaldehyde (AcH): 1000ppm

(ca. 15 mmol)300-W xenon lampFull arc irradiation:

300 < l < 500 nmWith L-42 cutoff filter:

400 < l < 500 nmGas phase analysis: on-line GC

photocatalytic activity test (gas phase)

2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 36Time / minTime / min

Am

ount

of g

as /

Am

ount

of g

as /

mmm

olm

olDarkDark

Light irradiationLight irradiation(400 < (400 < l l < 500 nm) < 500 nm)

COCO22ACAACA

PtPt--WOWO33 PtPt--WOWO33

TiOTiO22 P25P25 TiOTiO22 P25 P25

NN--TiOTiO22 NN--TiOTiO22

30

25

20

15

10

5

06050403020100

AcHAcH

AcH injected AcH injected （（1000 ppm, 1000 ppm, 15 15 mmmolmol））COCO22 generatedgenerated（（2000 ppm, 2000 ppm, 30 30 mmmolmol））

CHCH33CHO + 5/2 OCHO + 5/2 O22 →→ 22COCO22 + 2H+ 2H22O O

mineralization of acetaldehydemineralization of acetaldehyde


KKobsobs / min/ min--11

SiOSiO22/void//void/TiOTiO22SiOSiO22//TiOTiO2 2

TiOTiO2 2

(a) acetaldehyde(a) acetaldehyde

00 55 1010 1515 2020

R / R / μμmolmol･･minmin--11

/void//void/TiOTiOTiOTiO2 2

(c) PVA(c) PVA

00 0.20.2 0.40.4 0.60.6



TiOTiO2 2

(b) acetic acid(b) acetic acid

00 0.50.5 11 1.51.5 22

KKobsobs / min/ min--11


TiOTiO2 2

(a) acetaldehyde(a) acetaldehyde

00 55 1010 1515 2020


22TiOTiO2 2

(c) PVA(c) PVA

00 0.20.2 0.40.4 0.60.6



TiOTiO2 2

(b) acetic acid(b) acetic acid

00 0.50.5 11 1.51.5 22

hollow corehollow core--shell photocatalyst particlesshell photocatalyst particles

100 nm100 nm────

光触媒005 2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 38

unique characteristic of photocatalysisunique characteristic of photocatalysis

no need to use oxidants and no need to use oxidants and reductants for redox reductants for redox reactionreaction

no need to use electrolytes no need to use electrolytes as used in electrolytic as used in electrolytic redox reactionredox reaction

no need to use additive and no need to use additive and no emission of byno emission of by--productsproducts


redoxredox--combined photocatalytic reactioncombined photocatalytic reaction

example: photocatalytic synthesis of pipecolinic acid (PCA) fromexample: photocatalytic synthesis of pipecolinic acid (PCA) from LL--lysinelysine

LL--lysine ($1/1 kg) lysine ($1/1 kg) →→ PCA ($500/1 gPCA ($500/1 g））

ピペコリン酸001 2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 40

photocatalytic synthesisphotocatalytic synthesis

oxidation of amino group by hoxidation of amino group by h++

hydrolysis of imines to give hydrolysis of imines to give aldehyde or aldehyde or ketoneketone

Schiff base formation by Schiff base formation by dehydrationdehydration

reduction by ereduction by e--

--HH22OO

HHNN NNHH22

CCOOOOHH

HH22NN NNHH

CCOOOOHH

--HH22OO

HH22NN NNHH22

CCOOOOHH

HH22OO --NNHH33 HH22OO --NNHH33

HHOOCCNNHH22

CCOOOOHH

HH22NN OO

CCOOOOHH

NN CCOOOOHHNN CCOOOOHH

NNHH

CCOOOOHH NNHH

CCOOOOHH

ppiippeeccoolliinniiccaacciidd ((PPCCAA))

ccyycclliicc SScchhiiffffbbaassee

LL--llyyssiinnee ((LLyyss))εε

αα

22ee--,, 22HH++ ((PPtt))22ee--,, 22HH++ ((PPtt))

22hh++ --22HH++

ピペコリン酸004 2010/04/072010/04/07——Environmental Application of Photocatalysis Environmental Application of Photocatalysis 41

N

HN

NH2

O

NH2

ONH

COOH

O COOH

NH

NPh

HOOC

H

N

NH

O

NH NH

HN HNCl

H

H

H

HCl

O

ON

NH PhO

inhibitor of protein kinase C

Perumattam, J.; Shearer, B. G.; Confer, W.; Mathew, R. M. Tetrahedron Lett. 1991, 32, 7183-7186.

2 steps 8 steps

local anesthetic (Astra, Sweden)

Federsel, H. J.; Jaksch, P.; Sandberg, R. Acta Chem. Scand.

Ser. B 1987, B41, 757-761.

antitumor antibiotic DKP593A

Gitterman, C. O.; Rickes, E. L.; Wolf, D. E.; Madas, J.; Zimmerman, S. B.; Stoudt, T. H.;

Demmy, T. C. J. Antibiot. 1970, 23, 305.

several steps

mycotoxic alkaloidVerruculotoxin

Martens, J.; Scheunemann, M. Tetrahedron Lett. 1991, 32, 1417-1418.

3 steps

angiotensin conversion enzymeinhibitor

Flynn, G. A.; Giroux, E. L.; Dage, R. C. J. Am. Chem. Soc. 1987, 109, 7914-7915.

L-pipecolinic acid

fine chemicals from pipecolinic acidfine chemicals from pipecolinic acid

RopivacaineRopivacaine


mini testmini test

(1) (1) Name and matriculation card numberName and matriculation card number(2)(2) Explain briefly Gibbs energy and activation energy.Explain briefly Gibbs energy and activation energy.(3)(3) What do you expect to photocatalysis?What do you expect to photocatalysis?

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