HWAHAK KONGHAK Vol. 41, No. 4, August, 2003, pp. 542-548

���� ��� � TiO2 �� ���� � �� ��

���†� ���*����� *

�������� ����429-712 � ��� ��� 332-1

*�������� ����� ·�����305-343 ��� � � �� 71-2

(2003! 2" 7# $%, 2003! 4" 14# &')

Effects of Transition Metal Ion Doping on the Photocatalytic Reactivity and Physical Properties of TiO2

Sangeun Park†, Hyunku Joo*, Younggu Kim and Myungseok Jeon*

Gas Instrument Research Team, Korea Gas Safety Corporation, 332-1 Daeya-dong, Shihung, Gyonggi-do 429-712, Korea*Energy Conversion and Storage Research Center, Korea Institute of Energy Research,

71-2 Jang-dong, Yusung-gu, Daejeon 305-343, Korea(Received 7 February 2003; accepted 14 April 2003)

� �

� ����� �� �� � ����� Fe3+, Co2+, Ni2+� Mo5+, Nb5+, W6+ ��� TiO2� ��� �� ��� �

� !"# $"%&' ()*+, , ��-� .//0' 12*34 *56. 78� 9:� �!"; trichloroethylene

(TCE)� <*+ GC-ECD, FTIR �=3 GC-MS' >?*5 @, $"AB; XRD, SEM, UV-Vis, TG/DSC, FTIR �=3

XPS� ()*56. CD 9:� E�F7 GB �8� HIJK @, SEM LM� �N O 20 nm� ,P� QRS� AB

*56. !"TU V $"AB�� , ��� �� W/X YZ[ �F\�], Mo5+, Nb5+, W6+� Y^& GB_�, UV `

(, TCE LN�� Fe3+, Co2+, Ni2+� Y^a6 bc �d @, e4� Y^ XPS LM� �*+ 6f� g_.h& �

d �, i4� Y^� g_.h& HIJ� jk6. 6f� g_.h� e4/Bl L=� �m� n o � >:J@, [p

CD q"LM r; �_st !"� �m� �� o � uvw x� oy[6. e[z{ ��� Y^ �� $|� }~#

[' <� ��J� $" ��[ ^ ��� �� ���� ��*56.

Abstract − In this study, we investigate the physical properties and photocatalytic activities of TiO2 thin films doped with

low valence (Fe3+, Co2+, and Ni2+) and high valence (Mo5+, Nb5+, and W6+) cations. Photocatalytic activity was measured with

trichloroethylene (TCE) degradation, while films were characterized by XRD, SEM, UV-Vis, TG/DSC, FTIR, and XPS. All

samples prepared were in anatase phase with 20 nm film thickness. As a result, there existed a consistency that crystallinity,

UV absorption at 360 nm and TCE conversion were higher in case of high valence cations than in case of low valence cations.

In addition, even though various oxidation states for Mo5+, Nb5+, and W6+ were confirmed, those were not identified for Fe3+,Co2+, and Ni2+ thin films. The presence of different oxidation states of dopants and a higher degree of crystallinity seems to be

beneficial for retarding charge pair recombination processes in the TiO2 lattice.

Key words: Transition Metal Doped-TiO2, X-Ray Photoelectron Spectroscopy (XPS), TCE Degradation, FTIR, Physical Properties

1. � �

��� ����� � � � ������ ���, �� �� �

� ��� ��� !"# �$� %&' ()* +� ,�� �-�

� �� ��[1, 2]. ./0 ���1 2$� 34 56�7# �89:

;< )�# %=>? !"�7@ �A B: ,�� C��� ��.

�DE B: �89: ���# �A FG HIJ KLM N��� O

PQ ���[3-5], �R��@ %=>1 S� �<>� #� TUHVW

# XY� �Z��. �/� �<? ���1 2$� !"# 89[

�� \� SI] TiO2 ���# ^U: _: 2`, �a<`, �$R

�` N�� bU� 6$��� �c deI@ fg h I0� OPQ

i�. ./j� �/� ^U�0 k�l ��� ^m n� opqr s

: tuv� wx�� �� �@y, 8o��� HIJ KLM[ XY

\p0 fzI� SI] H�{|[ }�T(~�T)� �$I@ fg

� . I0��. ��7 � tu�7@ ��� ~�T# Ti �� (�†To whom correspondence should be addressed.E-mail: parkse@kgs.or.kr

542

��� �� TiO2 ��� 543

9�%# u3� �� 3���# ~�T[ �<I] ��� 2`, ��

�>%�, �� ;`, ��� ;`, L<%, L<>�# ��1 �� t

uI��.

2. � �

2-1. TiO2 �� � �� �� �

��o<: titanium isopropoxide(TTIP)[ ��34 \@ ��g�

#4 �[ ��I� indium tin oxide(ITO, 100 mm�25 mm�1 mm)1

zz�� dip ��I] �� ��[ ��I��. �� Hu��7

Aldrich# molybedeum chloride(MoCl5), niobium chloride(NbCl5),

tungsten chloride(WCl6), nickel chloride(NiCl2), cobalt chloride(CoCl2),

iron chloride(FeCl3)1   �% <� ¡� $I��. �� {| Hu

� �: ¢¢ 0.05 atomic %� }�I��. �£¤� �� {|# Hu

�1 ¢¢ }�I] 2 ¥ �5 ¦� TTIP1 §���� ¨� 103 �

5 © ¦, ��34 ª��Z 35% HCl[ }�I� 2 ¥ � �5

I] ��I��. 35% HCl� «¬? T+[ ­�I] �� T: }�

Iz ®¯�. Ti[OCH(CH3)2]4:C2H5OH:HCl(35 wt%)# ° �9:

1:40:0.1# �9� ��I��. Dip ��� #� ITO glass@ 103 ±a

500oC�7 ��²I���, ��: ��� 34 56� $�� S�

�<� �� -³1 SI] 10 5´I] ��o ��²1 I��.

2-2. �

6�z {|�� ��# L<u� 3µ: 500oC�7 103� 10 �

�o ��² o<[ p¶ �� ��� �47 X� ·3µ�(XRD,

Rigaku, D/MAX-IIIC, Japan)1 �$I��. 2θ ¸S@ 20o-80o�7 !

¹ |�@ 3& 3o� º<I��. ¢¢# {|� ��? �� ��# -

³» �� %� �¼z@ SEM(Topcon SM-720, Japan)�� 3µI�

�. ��? ½¾� �47 ¿<À�7 Á0Â� à ÄÂÅ u��# %

H� Æ�, ÇÈ ¬�T �p à É�# L<`c Æ�1 L<I� S

� ��² YÊ ¥, Æ�ËÌÍ ¿EXÎ n �3µÏÐ@ differential

scanning calorimeter(DSC, Mettler Toledo, DSC821e)» TG-DTA(Mettler

Toledo, TGA/SDTA851e)1 �$I] 3µI��. ��# Æ�» m�

Î: indium�� C<I��. FTIR(Bomem MB-series)3µ[ SI]

� %��7 �%�� Ñ�I] 3Ò%�� +Ó ¦, KBro UÎ��

ÔMI] pellet À�# Õ!Ö� +v� Æ� ��²� �G ¬�TU

# �p �×, Ti-OH ÈK ]q, Ti# ØZ[ SI] b I��. Ù�,

trichloroethylene# �34 56[ SI] b ¥ 3µ� �W� FTIR

56�1 �ÚI] GC/MS 3µo  ~� q�T# <`ØZ� �$I

��. ¢¢# ��? ����# ��� ;`: UV-vis(Perkin Elmer

Ramda, USA)� 3µI��. ��? ���# �34 ̀ W# ��1 S

4 TCE1 �ÛI���, TCE 3456 Ü�Ý�@ 200 ppmv�� º

<I��. ÞßÀ 3à 56�1 �$I��, UVA áâ(black light

fluorescent, 15 W, GE Co., USA)1 �Þ�� �$I��. �ã�@ (

äc 360 nm�7 UV intensity meter(Minolta Co. Ltd., Japan)� å<

I��. 3µ: ECD(electron capture detector)� cæ? �!Ö�çè

.éê(GC, HP-5890 serious II)� 3µI��. ëì: í ̀ëìZ HP-5

(25 m�0.32 mm, 0.50µm film thickness)1 $I���, 56 q�T

# <`ØZ: HP-5MS(50 m�0.2 mm, 0.4µm film thickness)1 $

I] GC/MS(GC-6890, MS-5973, HP.Co.)� 3µI��.

3. �� �

3-1. � �� ��� TiO2� �� �� � ���

�%��7 �>? äA @ 24 ¥ %Æ�7 Ñ�I���, 10-16 g

# ½¾ Ð@ UY 3S��7 TGA-SDTA, DSC3µ[ I��(Table 1).

6�z ��# ��? ���7 î- 3Ò� �æ? T# ï�(dehydration)

# Lo� 120oC�7 m�êÖ� 0Âð�, Æ�� ¤�ñ�ò 250oC

(Ni-TiO2@ 290oC) d��7 5�z ���� î- Ti Hu�Z TTIP#

isopropoxide à �� ��# ÇÈ ¬�T 34� #� m�êÖ1 C�

� ���, 300oC d��7@ ��{|# Hu�Z chloride# ïóY

>� ��êÖ� 0Âð�. L<% H� Æ�1 ØZI� S� 3µ�

7@ ¢¢ �� TU# ��� �� Á0Â� L<��# H�� ¢¢

�G Æ��7 0Âð@y, ¿<À�7 Á0Â��# L< ôÀ[ 360-

400oC ̧ S�7 Å�0� ��. m�êÖ# ��(∆H : J/g): Mo>Nb>W>

undoped-TiO2>Ni>Fe>Co# �7� 0Âð��, _: ÞÏ� ��Æ

(high valence cation : Mo, Nb, W)� ��? TiO2� B: ÞÏ� ��Æ

(low valence cation : Fe, Co, Ni)� ��? , C� Á0Â��# L<

ôÀ�@ Æ�� õ 20oC   ö÷ 0Â0@ øù� �×[ C](�

��. �@ �È# tuLo�7�ì, HÏ(E�7 ��? Mo, Nb, W

@ �� TiO2# %H� Æ�1 õ 20oC Bú � ��� OPQ ���

[6], Ù� HÏûE TU h Ti üÏa# Fe@ Á0Â� L<�7 ÄÂ

Å L<��# Æ�� BÁz@ ,�� C�? ý ��[7]. þÿ] ÒI

� L<% H�Æ�@ ��? ��� #� Ë×�+ Á�� Ti Hu�

# ��, ��? H�{|o# ÞÏ�, ��34� $? ��# ��,

�> Æ�, ¢¢# �G ��o<� �� V�w�� C����[8, 9].

S# Lo�� TiO2@ 400oC [10], 400-450oC à 400-500oC [11]�7

¿·<�7 Á0Â�� L<ô>� Å�0�, Á0Â��7 ÄÂÅ�#

%H�@ 600-800oC [12], 730oC [13], 800oC [14]�7 ���@ ,:

� OPw b�0, 25-650oC ¸S�7# DSC 3µ Ã 25-1,000oC

¸S�7# DTA(data not shown)3µ Lo�7@ ÄÂÅ ôÀ� �G

��� m� êÖ� 0Â0z ®¯�. Ù�, Fig. 1# XRD 3µ�7�

��� ÄÂÅ êÖ� ØZ�z ®¯��, TiO2# Á0Â� L<u�

(JCPDS File No. 21-1272)1 0�@ 25.38(101), 38.14(004), 48.04

(200), 55.02(105)# 2θ ¢�7 øù� êÖ� C](� ��. Table 1

� 0Â� ¢ �� ��# %�� L<>�(crystallinity)@ ��Iz ®

: TiO2# �Î[ ���� ­����. Nb, Mo, W-TiO2# %��

L<>�@ ���z ®: TiO2 �+ Á��, Fe, Co, Ni-TiO2 C�  

_: Lo� 0Âð�. L<>�# Ö� �7@ Fig. 4» 5�7 C](

� �@ TCE �34 89# �7» ÅI� ��.

Ð# ÇȬ�To �æ? �3# 39� �� DTA» TG .éâ

Fig. 1. XRD patterns of the various metal doped-TiO2 thin films for 10min calcination at 500oC.

HWAHAK KONGHAK Vol. 41, No. 4, August, 2003

544 �� ��� ��� ��

-

» �� y�r1 Table 1� 0Â��. ¿E XÎ 39: Nb>W>Mo>

pure-TiO2>Fe>Co>Ni� ��? TiO2# �7� ¢¢ 66.57, 56.19, 55.94,

52.88, 39.55, 38.19, 36.47%��. 300oC qd�7 ïóY>�#� ¿

EXÎ: Mo, Nb, W# ��HuTU# chlorine# ° �� Fe, Co, Ni

C�   _� N�� 5, 6�» �� Ti C� _: ÞÏ� ��Æ� ��

? TiO2�7 _: ïóY> 39[ 0Â�� ���, DSC 3µ Lo»

ÅI@ Lo1 C](� ��.

3-2. FTIR ��

FTIR 3µ[ SI] 25oC�7 24 ¥ Ñ� © {|�� ��@ �

�# ��1 p# Iz ®@ KBro UÎ�� ÔMI] Õ!ÖÀ�#

½¾� +v��. �� ��� H2O 3Ï# õ� >��æ[ 3,000-3,400

cm−1�7 ���v# ��w±�� 0Â0� ��[15, 16]. 1,621 cm−1

# êÖ@ hydroxyl .�(OH−)# w±[ 0Â��[17], TTIP# -CH2

» -CH3# êÖ@ �� à ��� w±�� 2,969, 2,927, 2,865 cm−1

�7 C](� ��. 1,441 cm−1# êÖ@ isopropoxide# �� dimethyl

�» -CH# ��� w±# Lo N���. � �� 1,383 cm−1o 1,278

cm−1: isopropyl �, 1,125 cm−1: isopropyl alcohol# C-O ��w±

(>CH-OH), 1,087 cm−1o 1,040 cm−1: ethanol# C-O ��w±(-CH2-

OH)[ 0Â�@ øù� ;`êÖ� 0Â��[18]. 200oC ��² ¦,

isopropanolo ethanol# ;` êÖ�7 �IE �æ? C-C and C-OH

groupv# 1,125, 1,087, 1,040 cm−1, 1,085-1,030 cm−1�7# êÖ@ p

# ��v��[16]. 300oC ��² ¦, Hu��7 TTIP# êÖv: î

- ����, �@ DSC �3µ�7 250-300oC d��7 m�êÖ@

¬�ÇÈT# 34� #� Lo1 �û� 4(� ��. Ti-O# ��w

± êÖ@ 550 cm−1 [9], 624 cm−1 [10], 653-550 cm−1 [15], 687 cm−1 [19],

511.9 cm−1 [20]�7 0Â��� C�I� ��. KBr(a)[ ý�b��

� � ,o KBr+pure-TiO2(b) ý�b�[ ß4 Nb0.005Ti0.995O2# Ti-O ;

`êÖ1 Fig. 2�7 C](� ��. Fig. 2(b)�7@ 891 cm−1Áé A u¥

�7 0Â0z ®¯�. ��7 A u¥# 717o 810 cm−1@ Nb0.005Ti0.995O2

# Ti-O ;` êÖ� Ð?�. �� 3S��7 Nb0.005Ti0.995O2# �

�² Æ�� �� Ti-OH, $�# O�¤.�, Ti Hu�# ;`êÖ1

ØZI��. 200oC�7 103¥ ��²� �A 0Â0z ®:

isopropoxide êÖ@ DSC�7# ÇȬ�T 341 0Â�@ m�êÖ

# Lo1 ��4(���, -CH2-CH3- (2,969, 2,927, 2,865 cm−1), Ti-OH

(1,621 cm−1), alcohol (1,125, 1,087, 1,040 cm−1)# 0�z êÖv:

300oC ��² ¦�@ H� C�z ®¯�.

3-3. UV-Vis ��

Ï � ËÌ+[ $4�I@ TiO2# � [ í´IP@ s: tu

Lov� m����. � � ÌÌ��# Ø�1 S� !"h# I0Z

Fe, Cr, Ru, V, Mo, Mn, Rh [21]» �: H�{|[ ~�T(dopant)�

�$I@ ,��. Fe# �A, ���@ FeÞÏÝ�� 1 atomic %1 #

[ �A ÔM�>T(Fe2TiO5)# À�0 $�>T(hematite)[ %`IE

?�@ C�� #4 �� äc ËÌ[ � ��� &' � ��@ ,:

� OPw b��. 0.05 atomic %# �� 6�z H�{|� ��

? TiO2# UV-Vis ��äc[ Fig. 3� 0Â��. øù� ��1 0Â

( +)# s: ��*�0 _: �� Ý�� Á�� *z��, Fe3+

(430 nm), Co2+ (415 nm), Ni2+ (450 nm)» �: HÏûE ~�Tv�

HÏ(E Ì*[ I@ Nb, Mo, W C�   red-shift� Lo1 C��.

./0 �34 56� $�@ UV-A áâ# É� äcã�Z 360 nm

�7# UV-Vis ���@ Nb- (0.6504), W- (0.6026), Mo- (0.4867), Co

Table 1. DSC, DTA and TG results of transition metal doped TiO2 with 0.05 atomic %

Dopant Analysis

Undoped TiO2 Fe Co Ni Mo Nb W

DSC ∆H (J/g) 228.89 211.36 206.98 214.40 258.40 259.90 242.33Peak (oC) 397.68 393.04 396.55 405.95 377.73 381.93 379.07Crystalli-nity (%) 100.00 92.34 90.42 93.85 112.89 113.54 105.87

DTA oC/g 39.11 23.56 24.95 8.25 39.12 42.06 36.53Onset (oC) 383.49 400.14 389.26 508.65 359.79 359.58 363.30Endset (oC) 416.30 425.62 431.79 615.39 393.00 394.96 406.63Integral (s oC) 253.33 311.73 327.58 65.78 410.29 367.30 403.53

TG Weight loss (%) 52.88 39.55 38.19 36.47 55.94 66.57 56.19

Fig. 2. FTIR spectra of Nb0.005Ti0.995O2 without calcination: (a) KBrblank, (b) KBr+pure-TiO 2 blank.

Fig. 3. UV-Vis spectrum of various metal-doped TiO2 thin films with500oC calcination for 10 min.

���� �41� �4� 2003� 8�

��� �� TiO2 ��� 545

(0.4652), Fe- (0.4380), Ni- (0.3739)� ��? TiO2 .²� ��Iz ®

: TiO2 (0.3451)# ��� 0Âð�. �/� �×[ TCE �34 56

(Fig. 4)o ��I� ¢¢# ���� ���ã�(Nb>W>Mo>pure-

TiO2>Co>Fe>Ni)» TCE �p89(Mo>Nb>W>pure-TiO2>Fe, Co, Ni)

# �7�@ ��� �z+, _: ÞÏ# ��Æv� ��? TiO2.�

� B: ÞÏ# ��Æv� ��? TiO2.�C�   _: TCE �p 8

9[ 0�� ��. Red-shift� #4 %���� Mo, Nb, W-TiO2C

�   s: � � ËÌ# + ��� Fe, Co. Ni-TiO2# �34 `W:

,ÁQ�Iz+, UVA áâ((äc 360 nm) $�� 360 nm �%�

7 0�@ � �äc: p# ¡� N�� B: TCE �p89[ C�

@ �¬ h# I0�� Ð?�.

3-4. XPS ��

��? �� ��# îÓ L|�-z@ �q��T�7 C 1s# L|

�-zZ 284.8 eV1 ���� I��. ¢¢# Fe, Co, Ni, Mo, Nb, W-

TiO2» pure-TiO2 �� ��� �� �� �>%�1 ��I��. Fig. 6(d)

�7 Mo-TiO2# �34W XPS !./�@ ]/ ^# Mo 3d !0¢

[ �z@ �A ́ 1� À�1 C](� ��. J[ À`I@ !0¢ 3

² �-z@ î- 3.2 eV��[22]. 2 34, êÖ A(Mo 3d5/2)» B(Mo

3d3/2)@ Mo5+# �>%�1 0�� 231.1 eVo 234.3 eV� S4

��. - 34� MoO2# À�� Mo4+# �>%�1 C](@ êÖ

C(Mo 3d5/2)» D(Mo 3d3/2)# L|�-z@ ¢¢ 230.1 eV» 233.3 eV

��. 232.6 eV» 235.6 eV� S� êÖ E(Mo 3d5/2)» F(Mo 3d3/2)

@ <5�� MoO3# À�� Mo6+# �> �S1 C�� ��[22, 23-25].

Moo# �>�S@ 228.8 eV» 232.0 eV�7 ¢¢ êÖ G(Mo 3d5/2)»

H(Mo 3d3/2)� 0��. ��7 Mo� ��? TiO2 �����7 Mo

# �� �>%�@ 0, 4+, 5+, 6+� ÈK��[23-25].

Fig. 6(e)@ NbO2# �>TÀ�� Nb4+# �>%�@ êÖ A(Nb 3d5/2:

205.0 eV)» B(Nb 3d3/2: 207.8 eV)� 4&��. op tuLo�@ Nb2+,

Nb4+, Nb5+ %�� �� Nb 3d5/2 L|�-z� ¢¢ 203.9eV, 205.9 eV,

207.2 eV� C���@y[22, 26] � tu�7� �» 6 �� ¡� Nb5+

# �>%�� C(Nb 3d5/2: 206.6 eV)» D(Nb 3d3/2: 209.4 eV)êÖ�

�6��. L|�-z# �±� #4 Nb4+(NbO2)� �� Nb 3d5/2,

205.0 eV(êÖ A)@ �� L|�-zC� 0.9 eV _: Lo1 C��,

NbO� 4&I@ êÖ E(204.7 eV)@ êÖ C(206.6 eV)C� �A Ú�

N�� Nb5+� Nb2+C�   s: À�� ÈKI²� Ð?�. Lo�

��, Nb-TiO2 ����: �q3 Nb5+» Nb4+�� Nb2+À�� ÈK

I� ��[27, 28].

W� ��? TiO2(Fig. 6(f))# �A, 35.7 eV» 38.1 eV�7 êÖ A(W

4f7/2)» B(W 4f5/2)@ W6+ �>%�1 0Â��[29], �@ tungsten(VI)

trioxide power(WO3)# L|�-z» � ÅI� ��. W5+ and W4+

# �>%�1 C�@ êÖ C» D@ 34.6 eV» 33.9 eV� SI� �

�[22, 30-32]. �/� Lo@ � tu�7# W-TiO2@ W4+, W5+, W6+

# ÔM? �>%�� u`�� �@ ,�� 7�?�.

5�, Fe-, Co-, Ni-TiO2 �� ��# XPS 3µ�7@ Fe 2p, Co 2p,

Ni 2p� �� {|�Æ �>%�� uÍ�@ øù� êÖ@ 0Â0z

®¯�. �/� 8%: high valence cation� ��? ��# XPS Lo

» 9H' %5�@ Lo1 C�� ��. ��7 �� ��# �Æ�>

%�# qK@ ���56�7 KLM fz1 S� HÏ-<�[ /:I

� ;v� Lo��� B: �34 89# Lo1 �Q�E ?�. 5�,

HÏ(E Ì*[ I@ 5, 6� H�{|v� ��? ��» �� ���

��� �>%�� ÈKI�, KLM fz1 S� /:Ú$� + Á�

� ¢¢ �>�S� �G {| �Æ# HÏ /:� #� HÏ/<� H

V �W[ ×% \E �� H5��� ��� 2`[ �� \@ Þ

Zh# I0�� Ð?�. �� �� <%b��7 ¬� Lo� m

����[33, 34].

3-5. TCE �� ��

��? ��# �2`: TCE# �34 56� #� H�9� =�I

��(Fig. 4). Nb-TiO2» Mo-TiO2@ 303, W-TiO2@ 503 ¦� TCE#

100% H�9[ >: 5�, Fe-, Co-, Ni-� ��? TiO2 �A@ +�

703 ¦�� 30%# H�9�� ¼z ?I� ��. 56To q�T#

<Î, <`� 3µ: 56 ¥� �� W-TiO2 �� ��� �47 in-situ

56�1 �$4 FTIR� 3µ� Lo@ TCE �+ Á�� dichloroacetyl

chloride(DCAC), carbonyl dichloride(COCl2), CO, CO2� �I] Table 2

� �� y�r» «³ ÊõI��. §����, Fe-TiO2, undoped-TiO2»

Nb-TiO2# FTIR ��9[ Fig. 5�7 0��. Fig. 5(a)# Fe0.005Ti0.995O2@

TCE# ( êÖZ C-Cl ��w±(630, 788, 845 cm−1), C-Cl ��� �

�w±(939 cm−1)êÖ@ �� 603 ¦�� p# ô>� ¡��,

DCAC1 0Â�@ C-Cl ��w±(738 cm−1) êÖ� Fig. 5(c)# DCAC

êÖ� �4 �A Ú�. 5�, Nb0.005Ti0.995O2 Fig. 5(c)�7@ � 103

±a# �56� TCE ( êÖ� 9H' �z� q�TZ DCAC(738,

805, 981, 1,073, 1,213 cm−1)# ( êÖ î- øù� 0Â0� ��. 5

6 203 ¦�@ DCAC# ��� êÖ� C�z ®�� k�l phosgene

êÖZ C=O(1,815, 1,827 cm−1)o C-Cl2(856 cm−1)� %`?�. ��I

z ®: �� TiO2 (b)# q�T %` ��@ Fig. 5(c)» ±ÅI�. .

Fig. 4. TCE photocatalytic degradation as a function of illuminationtime for various metal-doped TiO2 thin films (Initial Conc.=200ppmv, UV intensity=7.3 mW/cm2@360 nm).

Fig. 5. Comparison of TCE degradation by In-situ FTIR analysis ofthin films coated with (a) Fe0.005Ti 0.995O2, (b) pure-TiO2 and (c)Nb0.005Ti 0.995O2 (UV intensity=8 mW/cm2, initial TCE Conc.=2,000 ppmv).

HWAHAK KONGHAK Vol. 41, No. 4, August, 2003

546 �� ��� ��� ��

/0 34 56|�@ Nb0.005Ti0.995O2 Fig. 5(c)C�@   @²z+,

Fe0.005Ti0.995O2 Fig. 5(a)C�@ �A FA�@ ,[ O � ��. Co-»

Ni-TiO2# �A@ Fe-TiO2» �B� �×[ C](��. �34 =�

Lo _: ÞÏ� ��Æv� ��? TiO2� ÞÏ�� B: ��Æv

� ��? , C� TCE �34 89� �A _�@ ,[ GC» FTIR

3µ�� ØZI��.

3-6. �� �

����7 %���� B: �89# ÞZ� �@ KLM[ �� S

I], H�{|# ��[ �$I� ��. Mo5+, Nb5+, W6+» �: Ti4+

# �Æ �C�   s: high valence cation: TiO2 üÏ�# Ti4+ Ï

²� ���, dopant h o õIE LM�� �@ C]HÏ1 +v

E ?�. H�D# HÏ@ KLM ¡� Ti» üÏ �? ��{|v�

#4 /:�� � Lo� �¬D�@   s: <�� EÁ�E ?�. �

DE I] XY? KLM: super oxide �Õë(O2−F)[ %` \� S

� ��HI�± W"[   s� ×% \E �� Lo��� HIJ

� #�? )��� $�E �� 89� ��IE ?�.

Nb, Mo, W� ��? TiO2 ����# ��� �>%�@ �¬D�

7 <�/:, H�D�7 HÏ/: î- �WI�. �/� 8%: Grätzel

.��7 ESR3µ� #4 GH��, TiO2 üÏa� Mo6+» Mo5+� ±

� ÈK��� C�I��[34]. � tu�7� Nb5+» Mo5+# �>

%�� ÈKI@ TiO2@ �% TCE �34 56�7 %���� _:

�34 Lo1 >���, 34TU: �Az+ C�? tuLo[35-36]

»� � Å��. �È tuLo�7� {|�� TU# ���@ �

�� �z+ W6+, Ta5+, Nb5+� ��? TiO2# �Ym% |�� In3+,

Zn2+, Li+� ��? ,C� IJ   _�@ ,� C����[36].

5�, � tu�7 Fe3+ ��? TiO2# 3489: �A BE 0Âð

�. � Lo@ �G tu.�# b� Lo»@ �G �×[ C�� ��[33].

Fig. 6. The high resolution XPS spectra of various metal doped-TiO2 thin films: (a) Fe 2p (b) Co 2p (c) Ni 2p (d) Mo 3d (e) Nb 3d (f) W 4f spectra.

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Ö� * � ¡[ +) �A Ú�, Ù� Fe� ��? TiO2# �A Fe3+,

Fe2+, Fe4+ �> %�@ H� 0Â0z ®¯� N�� HI KLM fz

# Ì*[ Iz ?� ,� B: �3489# ÞZ�� 7�?�.

4. � �

HÏ (E Ì*[ I@ _: ÞÏ� ��ÆZ Mo5+, Nb5+, W6+� �

�? TiO2 �� ��# �% TCE �34 89: HÏûE�7 B: Þ

Ï� ��ÆZ Fe3+, Co2+, Ni2+� ��? TiO2C� IJ   _: Lo

1 0Â��. ��� 89# ��» XY@ ��? {|# ÞÏ�HÏ

� �� KA���.

(1) Mo, Nb, W� ��? TiO2 ���� ��# ��� �>%�@

TiO2 �q» ���7 �]�? HÏ» <�[ 3²I� �± \@y

��Iz ®: TiO20 Fe, Co, Ni-TiO2C�   8o�Z Ì*[ I��

. W4+, W5+, W6+(W-TiO2) Nb-TiO2# �>%�@ Nb2+, Nb4+, Nb5+, Mo-

TiO2@ Mo4+, Mo5+, Mo6+, W-TiO2@ W4+, W5+, W6+L[ XPS 3µ[

ßI] ØZI��. ./0 Fe, Co, Ni-TiO2# XPS êÖ ã�@ �A

Ú¯��, �>%� Ì 0Â0z ®¯�.

(2) Nb>Mo>W>prue-TiO2>Ni>Fe>Co-TiO2# L<>� �7@ TCE

�34 89# �7» ÅI�, Mo, Nb, W-doped TiO2# Fe, Co, Ni-

doped TiO2C�   _: L<>�, 360 nm�7# ���@ ��� 2

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� �

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Table 2. Main FT-IR peaks of reactant and by-products

Compounds Group and Class Peak from our experiment Reference peak wavenumber (cm−1)

reactant TCE C-Cl str. 630 (m) 629 (a,b,d)C-Cl str. 788 (s) 782 (a,b,c,d)C-Cl str. C-H def. 845 (s) 845 (a,b,c,d)C-Cl a.-str. 939 (s) 942 (a,b,c,d)C=C str. 1,255 (w) 1,253 (a.b)� 1,242 (d)CH-Cl bending 1,585 (w) 1,556 (a,b), 1,580 (d)C-H a.-str. - 3,097 (c), 3,070 (d)

by-products DCAC C-Cl2 sym.-str. 665 (w) 665 (a)C-Cl str. 738 (s) 739 (b)C-Cl a.-str. 805 (s) 803 (b)C-Cl2 str. 981 (s) 991 (b,c)C-C str. 1,073 (m) 1,077 (b)C-H bending 1,213 (w) 1,218 (b,c)

COCl2 C-Cl2 str. 856 (s) 858 (a) C=O str. 1,827 (s) 1,827 (a), 1,835 (b)

CO C=O a.-str. 2,130 (s) 2,112 (a,b)C=O sym.-str 2,170 (s) 2,140 (b,c)

CO2 O=C=O str. 2,332, 2,362 (s) 2,330. 2,370 (a), 2,353 (d)

(a) library data from Nist Webbook (http://webbook.nist.gov)(c) library spectra supplied by Nicolet (b) from chemosphere 36, 1998, 483-495(d) from J. Molecular Catalysis, 77, 1992, 297-311w: weak , m : medium, s : strong

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���� �41� �4� 2003� 8�