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1. �����2005B0894
2. ������� ����� ������������� !"#$%
(Effects of Additives in Preparation of Shape-Controlled Pt Catalyst for Polymer Electrolyte Fuel
Cells)
3. &'()�*+,-./�
&'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
C�'�^FD
0.5 M H2SO4�Im4Ar�K�30.9NqXO^�� ~��rs^FDt4�Aruv;��
XO����zwx�y�z^({,���FDEF��XK�������z|vE��zwx
��H����Q4_`K�^FPt�����_ng!}'(^EH"#,!$�Ft 6)��z|v
0.05 ~ 1.4 V�50 mV s-1�15¡q�M�)���{,��������0.05 ~ 0.85 V��z|v��
~'��M��Ow=!�A'�E��zwx�y�z^FD
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3.2 �� ¡¢�#��Ê9�ß
Fig. 2�Pt/PAA/I-
= 1/12/5 (10-4
M)~Pt/ PAA= 1/50 (10-4
M)#��à��«© Pt ¡¢��Ä+~��¤�±³
sÒë��u�ʧ¨©³sÒË�Ò�Ã�Ár
q#uv¤·���#�u���#³sÒË�Ò�Ã
�Árq�áN�O 0.55 V � Pt(111) ¯~0.27 V �
Pt(100) ¯~0.12 V �Pt(110) ¯�� ·�Í»â�ã�
�|��²ÝÞ§��N� 10-11)�Pt/PAA/I-
= 1/12/5#�Ö~
³sÒÃ@��OÍ»â�ã�O���Q¹ä©�¸�
O~Dåâãsætà���ÌÊ"sæt� Pt(111) ¯
�#âã���·�� Pt(111) ¯�¤�ä�«çä�N
�è®���²éê~Í»�±� (-0.1-0.05 V) à 10
³sÒÃÛN~�ÌÊ"sæt¤ Pt(111) ¯¹��ã«
���«©²¸� 12)~0.55 V y�� Pt(111) ¯�� ·
�²éê���Í»â�ã��|�©�¸#uv~Pt/PAA/I-
= 1/12/5 #��à��«©ª#OPt(111)
¯¤¦á tetrahedral Pt ¡¢�à��²éê����«¹«~�#Í»â�ã�O��Qª#àOQ
¹ä©��#� ²«��ã«©�ÌÊ"sæt�ë+ Pt(111) ¯�âã«�N�è®����ç
©~Pt/ PAA= 1/50 (10-4
M)#��à��«©Pt ¡¢��áN��u�Pt#D!à��0.13 V²0.27
V#�±�"#p$QÍ»â�ã�����~�u�¢�à��²éê����
3.3 �� ¡¢�#À%&'
Pt/Poly./I-
= 1/12/5 (10-4
M)#��à��«©Pt ¡¢
�ÎÏ#À% �S(Q)¤L(²«�Fig. 3�·�Q < 6
Å-1�)*�+N,pÒ��-.�§�©�̧ ��#,p
ÒO~ÐËÑÒËú ÓËÌq#/¤Í�Î&§¨©
0��1«�ª.�§���2~ÐËÑÒËú ÓË
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#g8945¤:ä�¶}«�N�¸²¤;�§¨©�
<��© S(Q)¤ª²�=ì//-T(r)¤>?«~�#
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²ÆQ�¸²�;�§�©�«¹«Q��~Fig. 4(a)#Pt�¶}·�T(r)àO~ì/,pÒ�3 Ź�
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)
- 194-
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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
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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)
- 195-
<
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- 196-
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