SPring-8 · SPring-8 1. 2005B0894 2. ˘ˇˆ˙˝˛˚˜ !"#$% (Effects of Additives in Preparation of...

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SPring-8 1. 2005B0894 2. (Effects of Additives in Preparation of Shape-Controlled Pt Catalyst for Polymer Electrolyte Fuel Cells) 3. (Inaba, Minoru) (0015064) (Shodai, Yoshio) (PD) (0007946) (Matsuzawa, Koichi) (PD) (0016354) (Yamada, Hirohisa) D2 (008776) (Aritomo, Hiroki) M2 (0013741) (Goto, Takashi) M2 (0016545) (Tokunaga, Junko) M2 (0016548) (Hatanaka, Aoi) M1 (0016356) (Hasegawa, Makoto) M1 (0016551) (Niina, Fumiharu) M1 (0016547) 4. BL04B2 5. The size and surface orientation of Pt nanoparticles greatly affect the catalytic activity for oxygen reduction in polymer electrolyte fuel cells. To understand the effects of size and surface orientation, Pt nanoparticles with controlled size and surface orientation were prepared. When the sodium polyacrylate (PAA) as a capping polymer and iodine ion (I - ) as a specific absorption anion were added in a molar ratio of Pt/Poly./I - = 1/12/5, tetrahedral Pt nanocrystals were successfully prepared at a yield of 70%. The adsorption state of PAA and I - ion on Pt nanoparticles was investigated by high-energy X-ray diffraction at SPring-8 (BL04B2). 1. (PEFC) PEFC (Pt) ( 2-3 nm) ( ) PEFC Pt (K 2 PtCl 4 ) ( ) H 2 Pt 2+ 1-2) 191

Transcript of SPring-8 · SPring-8 1. 2005B0894 2. ˘ˇˆ˙˝˛˚˜ !"#$% (Effects of Additives in Preparation of...

Page 1: SPring-8 · SPring-8 1. 2005B0894 2. ˘ˇˆ˙˝˛˚˜ !"#$% (Effects of Additives in Preparation of Shape-Controlled Pt Catalyst for Polymer Electrolyte Fuel

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1. �����2005B0894

2. ������� ����� ������������� !"#$%

(Effects of Additives in Preparation of Shape-Controlled Pt Catalyst for Polymer Electrolyte Fuel

Cells)

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&'01(�23 4 (Inaba, Minoru) 56789 :9;< => (0015064)

?5&'(�@A BC (Shodai, Yoshio) 56789< DEFGH(PD) (0007946)

IJ KL (Matsuzawa, Koichi) M�NOPQ< RSFGH(PD) (0016354)

TU VW (Yamada, Hirohisa) 5678989X:9FGY< D2 (008776)

Z[ \] (Aritomo, Hiroki) 5678989X:9FGY< M2 (0013741)

^_ ̀ (Goto, Takashi) 5678989X:9FGY< M2 (0016545)

ab c� (Tokunaga, Junko) 5678989X:9FGY< M2 (0016548)

de f (Hatanaka, Aoi) 5678989X:9FGY< M1 (0016356)

ghi j (Hasegawa, Makoto) 5678989X:9FGY< M1 (0016551)

k� lm (Niina, Fumiharu) 5678989X:9FGY< M1 (0016547)

4. n�opqrst�BL04B2

5. &'uv�wx� y

The size and surface orientation of Pt nanoparticles greatly affect the catalytic activity for oxygen

reduction in polymer electrolyte fuel cells. To understand the effects of size and surface orientation, Pt

nanoparticles with controlled size and surface orientation were prepared. When the sodium

polyacrylate (PAA) as a capping polymer and iodine ion (I-

) as a specific absorption anion were added in

a molar ratio of Pt/Poly./I-

= 1/12/5, tetrahedral Pt nanocrystals were successfully prepared at a yield of

70%. The adsorption state of PAA and I-

ion on Pt nanoparticles was investigated by high-energy

X-ray diffraction at SPring-8 (BL04B2).

1. z{

|}~��� ����(PEFC)O����������NO����������p��t�

#������~FG��������N��PEFC #�����O~�p�t���u�#��

(Pt)  ¡¢�(£ 2-3 nm)¤¥¦§¨©ª#¤n�«�N��L¬�~���#­®O��¢�#

� (¯°±) ²³s´�µ¶·�¸²¹�~PEFC#º»¼½¾¿.À#ÁÂÃ��²«�~ ��Ä

+¢Å#��§�© Pt  ¡¢�#���ÆDzQ��

�� ¡¢�# ���Ȳ«�~ÉÊ��º�ËÌqÍÎÏ (K2PtCl4) ²ÐËÑÒËú ÓË

ÌqÍÎÏ (ÐËÔp) ¤ÕÖ«~H2 ×ؤÙÚ§¨~ Pt2+

#¼½¤ÛÜ°È�ÝÞ§��N� 1-2)�

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���������� ����������������� Pt ������ !"#�$�

�%&�'()�!�*+,��-./�01!2���34�����56�78�9:;<=�

>?@AB4�C()�)DEF���GH4IJ�4G���KL�M��N�O���P+4�

Pt��QR���SN�TUV;WX�TU�0 YZ[\�]H^�_`�]!�abO4�c

^()��deA'�!�fg_`4h)(��3$E���'()�) 3)D

�ij����O4 Pt(111) g4TUk���'()�N�TUV;WX� �k�����

Pt(111) gQ�����l��5^���56�'F Pt ������ ����9:;<=�

@���^FD���N�TUV;WX�^(����XV;WX�m�Pt_nfg4�3��TU

k��o�pqWX 4-5)4U�^(NaI�����34 �^FD�^(��P+rs� @�F

t4uZfg��TU�fg_`���@AB4k��v!$���BASPring-8�BL04B2wX�

=�K��xyX���� !�c)(���SN�TUV;WX� Pt Q��"z�TU��

���^FD

2. {|��

2.1 uZ������

}�uZ~(K2PtCl4, #$�%�& )��I4V�M~��o= ([-CH2CH(CO2Na)-]n,

Aldrich � ) ��I�N�TUV;WX�^(�o�pqWX��'��M(��`^�pH = 7 4)

*^(�25 o

C �+,-.4/'FD�c^FV�M~��o=�01.�� (Mw) �5100

�$�D���`�I�2.434^�!A��I4 Ar �K (5678~�, G2 �99.9995%) �

90 .9�^�2.4:;��)���� H2 �K(�� <=>, Round Science, RHG-1000)� 10 .9

��^�Pt2+

�����CFD��,� 25o

C�^FDH2 �K������EE?wK��@A^

�B34^�Pt�������qC�I�� ^F 2)D

� ^F Pt ��qC�I�DE���FGH (TEM, HITACHI :H-9000) 4GC(������

�-�IJ��CFDTEMIJ4��Cu9KxL200 (MM=N�M�q��OKC) 4��P�

^Q,�RSk����T����F��Pt��qC�I�P�^�Q,�RS���U��^FD

2.2 uZ������;��VY

�;��W'4���XK���!OwKx�:��X(GC)�XO��!PtBA���YXO

�XK���(RRDE)�c)FDPt��qC�I�Z[.\�4G�]^^�GCQ4_`K���30o

C�

2a9b;m�RS��F3���c��^(c)FDZ[.\(TOMY, GRX-220)�20,000 rpm�17

.9�)�,�15o

C�^FDc�4Ptd�ef�!"g���� (RHE)�h�ijM��� I

4�0.5 M H2SO4 (�k���&, 98 %, l��)�c)FDmnio,+,�- (AS ONEpLTB-125)

�c)(�jM�,�25o

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0.5 M H2SO4�Im4Ar�K�30.9NqXO^�� ~��rs^FDt4�Aruv;��

XO����zwx�y�z^({,���FDEF��XK�������z|vE��zwx

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0.05 ~ 1.4 V�50 mV s-1�15¡q�M�)���{,��������0.05 ~ 0.85 V��z|v��

~'��M��Ow=!�A'�E��zwx�y�z^FD

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3.2 �� ¡¢�#��Ê9�ß

Fig. 2�Pt/PAA/I-

= 1/12/5 (10-4

M)~Pt/ PAA= 1/50 (10-4

M)#��à��«© Pt  ¡¢��Ä+~��¤�±³

sÒë��u�ʧ¨©³sÒË�Ò�Ã�Ár

q#uv¤·���#�u���#³sÒË�Ò�Ã

�Árq�áN�O 0.55 V � Pt(111) ¯~0.27 V �

Pt(100) ¯~0.12 V �Pt(110) ¯�� ·�Í»â�ã�

�|��²ÝÞ§��N� 10-11)�Pt/PAA/I-

= 1/12/5#�Ö~

³sÒÃ@��OÍ»â�ã�O���Q¹ä©�¸�

O~Dåâãsætà���ÌÊ"sæt� Pt(111) ¯

�#âã���·�� Pt(111) ¯�¤�ä�«çä�N

�è®­���²éê~Í»�±� (-0.1-0.05 V) à 10

³sÒÃÛN~�ÌÊ"sæt¤ Pt(111) ¯¹��ã«

���«©²¸� 12)~0.55 V y�� Pt(111) ¯�� ·

�²éê���Í»â�ã��|�©�¸#uv~Pt/PAA/I-

= 1/12/5 #��à��«©ª#OPt(111)

¯¤¦á tetrahedral Pt ¡¢�à��²éê����«¹«~�#Í»â�ã�O��Qª#àOQ

¹ä©��#� ²«��ã«©�ÌÊ"sæt�ë+ Pt(111) ¯�âã«�N�è®­����ç

©~Pt/ PAA= 1/50 (10-4

M)#��à��«©Pt ¡¢��áN��u�Pt#D!à��0.13 V²0.27

V#�±�"#p$QÍ»â�ã�����~�u�¢�à��²éê����

3.3 �� ¡¢�#À%&'

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= 1/12/5 (10-4

M)#��à��«©Pt ¡¢

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Å-1�)*�+N,pÒ��-.�§�©�̧ ��#,p

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2.8 Å��JÓ«�N�¸²�.�§�~Pt-Ptì/#¶}¤K«©�4 L6 Å#MNàì/,pÒ�

ON����©�FT-IR#uv¹�ÐËÑÒËú¤�N���«©Pt ¡¢�àOPtï�#���

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

0 0.2 0.4 0.6 0.8

Pt/Poly./I-

=1/12/5

After cycled

Pt/Poly.=1/50

E / V vs. RHE

I / m

A

Fig. 2 Cyclic voltammograms of Pt

nanoparticles before and after repeated

potential cycling at 50 mVs-1

in 0.5 M

H2

SO4

under Ar atmosphere.

0

1

2

3

4

5

0 5 10 15

Fig. 3 Structure factor (S(Q)) of Pt

nanoparticle colloids of Pt/Poly./I-

=1/12/5 (10-4

M).

r / Å

S(Q)

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Ã�P�ÃQ#Oï��uÖ«�N�²ÝÞ§���2 3)~�#ì/�ìF·�²�R§�©�~S

T#NUPt/Poly. = 1/50 (10-2

M)�1·�T(r)e(Fig.4(b))àO~�#ì/�V��.�§����W~

X�·��OY�Q¹ä©�

4. u{

PEFC#º»¼½¾¿.À#ÁÂÃ��¤Z[«�~ �#��§�© Pt  ¡¢�#��¤0/©�

DåâãÑðæt²«�~�ÌÊ"sæt¤�N~Pt/PAA/I-

=1/12/5#��à~tetrahedral Pt  ¡¢�

�£7\]T��§�©���Ê9���Ää�Pt(111)¯�Ää�À^§��Pt ¡¢�à��¸²

�DE§�©�«¹«Q��~À%ñQ&'¹�OÐËÔp²DåâãÑðæt²# !#Z3�Ä

�_O���W~tetrahedral Pt  ¡¢�# ^#`a²Q�âã�bO���DEàcQ¹ä©�

déef

1) L. D. Rampino and F. F. Nord, J. Am. Chem. Soc.,63, 2745 (1941).

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Fig. 4 Total correlation function (T(r)) of Pt nanoparticle colloids of a) Pt/Poly./I-

=1/12/5 (10-4

M) and b) Pt/Poly. =1/50 (10-2

M) with and without Pt nanoparticle.

0

5

10

15

20

0.5 2 4 6 8 10

r / Å

Pt+Poly.

Poly.

b)

T(r)/4(r)

0

5

10

15

20

0.5 2 4 6 8 10

r / Å

Pt+Poly.

Poly.

b)

T(r)/4(r)

r / Å

0

5

10

15

20

0.5 2 4 6 8 10

Pt+Poly.+I-

I-

T(r)/4(r)

a)

r / Å

0

5

10

15

20

0.5 2 4 6 8 10

Pt+Poly.+I-

I-

T(r)/4(r)

a)

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13) B. Hellquist, L. A. Bengtsson, B. Holmberg, B. Hedman, I. Persson and L. I. Elding, Acta Chem. Scand. 45, 449

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