2009B1874                        

BL14B2XAFS࡟ࡼࡿⓑ㔠ࢆ౑⏝ࡋ࡞࠸⇞ᩱ㟁ụࡢࡑࡢሙ ᐃIn situ XAFS Measurements of Precious Metal-free Liquid-feed Fuel Cellᒣᮏ ࿴▮ a, ᮅ⃝ ᾈ୍㑻 a, ᆏᮏ ཭࿴ a ⏣୰ ⿱ஂ a, す⏿ ಖ㞝 b, ⏣ᮧ ࿴ஂ b, ᯇᮧ ኱ᶞ b
Kazuya Yamamotoa, Koichiro Asazawaa, Tomokazu Sakamotoa, Hirohisa Tanakaa, Yasuo Nishihatab,Kazuhisa Tamurab, Daiju Matsumurabaࢲ࢖ࣁࢶᕤᴗ㻔ᰴ㻕, b㻔⊂㻕᪥ᮏཎᏊຊ◊✲㛤ⓎᶵᵓaDaihatsu Motor. CO., LTD., bJAEA, ࢔ࢽ࢜ࣥ஺᥮ᙧ⇞ᩱ㟁ụ࡟⏝࠸ࡽࢀࡿ࢝ࢯ࣮ࢻゐ፹ࡢᵓ㐀ࢆ᫂☜࡟ࡍࡿࡓࡵ࡟ࠊX ⥺྾཰ᚤ⣽ᵓ㐀㻔XAFS㻕ᐃ࡟ྲྀࡾ⤌ࢇ࡛࠸ࡿࠋ௒ᅇࡣࢥࣂࣝࢺ࣏ࣜࣆ࣮࣮ࣟࣝ࢝࣎ࣥ㻔CoPPyC㻕ࢆ◲㓟ฎ⌮ࡋ࡚ඹᏑ≀࡛࠶ࡿ Co㻔OH㻕2 ࡞࡝ࡢ㝖ཤࢆ⾜࠸ Co ࿘ࡾࡢᵓ㐀ゎᯒࢆ⾜ࡗࡓࠋࡲࡓ CoPPyC ࡜ࡑࡢ◲㓟ฎ⌮ࡋࡓヨᩱ࡟ࡘ࠸࡚ࠊ༙㟁ụࢭࣝࢆ⏝࠸࡚㟁఩ࢆ࠿ࡅࠊࡑࡢሙ㻔in situ㻕 ᐃࢆ⾜ࡗࡓࠋ࣮࣮࢟࣡ࢻ㸸 ⇞ᩱ㟁ụࠊ㠀ⓑ㔠࢝ࢯ࣮ࢻゐ፹ࠊXAFS⫼ᬒ࡜◊✲┠ⓗ㸸᪥ᮏ࡟࠾࠸࡚⮬ື㌴࠿ࡽᨺฟࡉࢀࡿ஧㓟໬Ⅳ⣲㔞ࡣ඲యࡢ⣙ᅄศࡢ୍ࡶ༨ࡵ࡚࠾ࡾࠊ2020 ᖺࡲ࡛࡟ 1990 ᖺẚ࡛ 25%๐ῶࡍࡿࡓࡵ࡟ࡣࠊ᪩ᛴ࡞ᢏ⾡㛤Ⓨࡀᚲせ࡛࠶ࡿࠋࡑࡇ࡛ḟୡ௦ࢡ࣮ࣜࣥᢏ⾡࡜ࡋ࡚ᮇᚅࡉࢀ࡚࠸ࡿࡢࡀࠊ㉮⾜᫬࡟ࡣ඲ࡃ ᐊຠᯝ࢞ࢫࢆ඲ࡃ᤼ฟࡋ࡞࠸⇞ᩱ㟁ụ㌴࡛࠶
ࡿࠋࢲ࢖ࣁࢶ࡛ࡣࠊ㟁ᴟゐ፹࡟㈗㔠ᒓࢆ౑⏝ࡍࡿᚲせࡀ࡞ࡃࠊ࢚ࢿࣝࢠ࣮ຠ⋡ࡀỈ⣲ࡼࡾࡶ㧗࠸ᾮయ⇞ᩱ࡛࠶ࡿỈຍࣄࢻࣛࢪࣥࢆ౑⏝ࡍࡿ⇞ᩱ㟁ụࡢ㛤Ⓨ࡟ྲྀࡾ⤌ࢇ࡛࠸ࡿ[1]ࠋ⌧ᅾࠊ✵Ẽഃࡢ࢝ࢯ࣮ࢻゐ፹࡜ࡋ࡚ Co ࡀ࣏ࣜࣆ࣮ࣟࣝ㻔PPy㻕࡞࡝࡟㓄఩ࡉࢀࡓ Co ࣮࢟ࣞࢺゐ፹ࢆ㛤Ⓨ୰࡛࠶ࡿࠋ㓄఩ᏊࡀᏑᅾࡍࡿࡇ࡜࡛ Co metal ༢⊂ࡼࡾࡶゐ፹άᛶࡀ㣕㌍ⓗ࡟ྥୖࡋ࡚࠸ࡿࠋࡑࡇ࡛㓄఩Ꮚࡢᙺ๭ࢆ᫂☜࡟ࡍࡿࡓࡵ࡟ in situ XAFS
2009A1938 ሗ࿌᭩[2]࡟࠾࠸࡚ࠊin situᐃ࡟ྲྀࡾ⤌ࢇࡔࠋᐃ࡛ CoPPyC ࡀ Co2+࠿ࡽ Co3+࡬ኚ໬ࡍࡿࡇ࡜ࢆሗ࿌ࡋࡓࠋࡋ࠿ࡋࠊᐇ㦂࣭ゎᯒࢆ㐍ࡵࡿࡇ࡜࡛ Co ࣮࢟ࣞࢺࡢ≧ែኚ໬ࡼࡾࡣࡴࡋࢁ Co Ỉ㓟໬≀࡞࡝ࡢඹᏑ≀ࡢ≧ែࢆᙉࡃ཯ᫎࡋ࡚࠸ࡿࡇ࡜ࡀศ࠿ࡗࡓࠋࡑࡇ࡛ࠊᮏᐇ㦂࡛ࡣࠊCo ࣮࢟ࣞࢺᵓ㐀ࡢᢳୗฟࢆ⾜࠸ࠊࡑࡢᵓ㐀ゎᯒࢆ⾜ࡗࡓࠋࡉࡽ࡟ in situᐃ࡛ࡢᵓ㐀ࡢኚ໬ࢆᤊ࠼ࡿࡇ࡜ࢆヨࡳࡓࠋᐇ㦂㸸
CoPPyC ࡢ◲㓟ฎ⌮࡟ࡼࡾ Co Ỉ㓟໬≀ࢆ㝖ཤࡋ࡚ Co ࣮࢟ࣞࢺᵓ㐀ࡢᢳฟࢆヨࡳࡓࠋࡋ࠿ࡋ Co⃰ᗘࡀపࡃࠊࢲ࢖ࣁࢶᡤ᭷ࡢ XPS ࡛ࡣ᳨ฟ㝈⏺௨ୗ࡛࠶ࡿࡓࡵࠊᢳฟࡋࡓᡂศࡢ≉ᐃࡀ࡛ࡁ࡞࠿ࡗࡓࠋࡑࡇ࡛◲㓟ฎ⌮ࡋࡓ CoPPyC ࢆࡼࡾ㧗ឤᗘ࡞⺯ගᆺ XAFS ࡟ࡼࡗ࡚ ᐃࡋࡓࠋࡲࡓ◲㓟ฎ⌮ࡋࡓ CoPPyC ࠾ࡼࡧᮍฎ⌮ࡢ CoPPyC ࡢ in situࢆࡑࢀࡒࢀᅗ 1ࠊ2 ࡟♧ࡋࡓࠋᐃࢆ⾜ࡗࡓࠋin situᐃ᫬ࡢ෗┿ࠊᐇ㦂㓄⨨X⥺

ᅗ 1. ᐇ㦂᫬ࡢࢭࣝ㓄⨨

e-Air
Beam
KOH
RE
Anion-exchange
membraneCounter electrode(carbon)
4OH䊻O2䠇2H2O+4e-

Working electrode(Samples)
O2䠇2H2O+4e䊻4OH-

ᅗ 2. ࢭࣝෆࡢ㟁ᴟ㓄⨨࡜཯ᛂᘧ ヨᩱࡣ࢔ࢽ࢜ࣥ஺᥮⭷ୖ࡟ሬᕸࡉࢀ࡚࠾ࡾࠊ⿬㠃࡟࢝࢘ࣥࢱ࣮㟁ᴟࡀሬᕸࡉࢀ࡚࠸ࡿࠋヨᩱ࡟ࡣ✵Ẽࢆ㏦ࡾࠊ࣏ࢸࣥࢩࣙࢫࢱࢵࢺࢆ⏝࠸ࡓ㟁఩༳ຍ࡟ࡼࡗ࡚཯ᛂࢆไᚚࡍࡿࠋXAFS ࡢᐃࡣ

Co-K ྾཰➃࡟࠾࠸࡚ Co ⃰ᗘࡢ㧗࠸ CoPPyC ࡣ㏱㐣ἲࠊCo ⃰ᗘࡢప࠸◲㓟ฎ⌮ࡋࡓ CoPPyC ࡣ⺯ගἲ࡟࡚ ᐃࢆ⾜ࡗࡓࠋ⤖ᯝ࠾ࡼࡧ⪃ᐹ㸸◲㓟ฎ⌮ࡋࡓ CoPPyC ࡜ẚ㍑ࡢࡓࡵ࡟ฎ⌮๓ヨᩱ࡟ࡘ࠸࡚ࠊᅗ 3㻔a㻕࡟ Co-K ྾཰➃ࡢ XANES ࢫ࣌ࢡࢺࣝࠊ
ᅗ 3㻔b㻕࡟ EXAFS ᣺ືࡢࣇ࣮࢚ࣜኚ᥮࡟ࡼࡗ࡚ᚓࡽࢀࡓ Co ࿘ࡾࡢືᚄศᕸ㛵ᩘࢆ♧ࡍࠋ
XANES 㡿ᇦ࠿ࡽ◲㓟ฎ⌮ࡋࡓ CoPPyC ࡢ Co ౯ᩘࡣ 2 ౯࡛࠶ࡗࡓࠋືᚄศᕸ㛵ᩘ࡛ࡣ◲㓟ฎ⌮ࡍࡿࡇ࡜࡛ 2.8ύ௜㏆ࡢᵓ㐀ࡀᾘኻࡋࡓࠋࡇࢀࡣ CoPPyC ୰࡟ྵࡲࢀࡿỈ㓟໬≀ࡢ Co-O-Co ᵓ㐀࡛࠶ࡾࠊ◲㓟ฎ⌮࡟ࡼࡗ࡚㝖ཤࡉࢀࡓࡇ࡜ࢆ♧ࡍࠋ࣮࢟ࣞࢺᵓ㐀ࡣ Co ཎᏊࡢ࿘ࡾ࡟ࡣ㓄఩ᏊࡀᏑᅾࡍࡿࡓࡵࠊ㛗㊥㞳ᡂศ࡛࠶ࡿ Co-O-Co ⤖ྜࡀᏑᅾࡋ࡞࠸ࠋࡇࡢࡇ࡜࠿ࡽ CoPPyC ࡣ◲㓟ฎ⌮࡟ࡼࡗ࡚ Co ࣮࢟ࣞࢺࡢᢳฟ࡟ᡂຌࡋࡓࡇ࡜ࡀ᫂☜࡜࡞ࡗࡓࠋࡉࡽ࡟ࡇࡢ Co ࣮࢟ࣞࢺࡢ⺯ගᆺ in situᐃࢆヨࡳࡓࡀࠊࢫࢸࣥࣞࢫࢭࣝ࡟ྵࡲࢀࡿ Fe ࡟ࡼࡗ࡚ᖸ΅ࢆཷࡅࠊ࢚ࢵࢪࢪࣕࣥࣉࢆほ ࡛ࡁ࡞࠿ࡗࡓࠋ

Co-O-Co ⤖ྜ㻔Co㻔OH㻕2㻕16

Intensity (arb. units)㻔a㻕㻔b㻕
|FT|

40.5

CoPPyC-AT
CoPPyC2CoPPyC-AT
CoPPyC

0077007720

7740
77607780
Photon Energy (eV)07800

123R(A)456

ᅗ 3. CoPPyC-AT㻔AT㸸Acid Treatment㻕࡜ CoPPyC ࡢ Co K ྾཰➃
㻔a㻕XANES ࢫ࣌ࢡࢺࣝ ࡜㻔b㻕Co ࿘ࡾࡢືᚄศᕸ㛵ᩘ ḟ࡟ࠊCoPPyC ࡢ㏱㐣ᆺ in situᐃࢆ⾜ࡗࡓ⤖ᯝࢆᅗ 4 ࡟♧ࡍࠋᅗ 4㻔a㻕࡟ࡣࠊCo-K ྾཰➃ࡢ

XANES ࢫ࣌ࢡࢺࣝࡢ㟁఩౫Ꮡᛶࢆ♧ࡍࠋ㟁఩ኚ໬࡟ࡼࡿ౯ᩘኚ໬࡞࡝ࡢ㟁Ⲵࡢ⛣ືࢆ♧ࡍࢫ࣌ࢡࢺࣝኚ໬ࡣ⌧ࢀ࡚࠸࡞࠸ࠊࡓࡔࡋ in situ ᮲௳࡟࠾࠸࡚㧗౯ᩘഃ࡟ࢩࣇࢺࡋࡓࠋᅗ 4㻔b㻕࡟ࡣ
EXAFS ᣺ືࡢࣇ࣮࢚ࣜኚ᥮࡟ࡼࡗ࡚ᚓࡽࢀࡓ Co ཎᏊ࿘ࡾࡢືᚄศᕸ㛵ᩘࡢ㟁఩౫Ꮡᛶࢆ♧ࡍࠋIn situ ᮲௳࡟࠾࠸࡚ 2.7ύ௜㏆࡟ぢࡽࢀࡓ Co-O-Co ࡢࣆ࣮ࢡࡀ 2.4ύ௜㏆࡟ኚ໬ࡋࡓࠋ㟁఩࡟ࡼࡿኚ໬ࡣᑠࡉ࠸ࡶࡢࡢ≧ែࡀኚ໬ࡍࡿᵝᏊࡀほ ࡉࢀࡓࠋኚ໬㔞ࡀᑠࡉ࠸ཎᅉ࡜ࡋ࡚ࠊPPy ࡟㓄఩ࡉࢀࡓ Co ࡟ᑐࡋ࡚ඹᏑࡍࡿ Co Ỉ㓟໬≀ࡀከ࠸ࡓࡵࠊಙྕࡀ㞃ࢀ࡚ࡋࡲࡗࡓࡇ࡜ࡀ⪃࠼ࡽࢀࡿࠋ
௒ᅇ⾜ࡗࡓᐇ㦂ࢹ࣮ࢱ࡟ຍ࠼࡚ࠊ2010 ᖺ 2 ᭶ 2 ᪥࠿ࡽ 6 ࢩࣇࢺࡢᐇ㦂࡛ᚓࡽࢀࡓࢹ࣮ࢱࡶྵࡵ
࡚ཎⴭㄽᩥ࡜ࡋ࡚ᢞ✏ணᐃ࡛࠶ࡿࠋ

䠉1100mV
䠉 900
䠉 850
䠉 800
䠉 750
䠉 700
䠉 600
䠉 400

㻔a㻕
1.00.51100 to 400mV vs.RHE
Co-O-Co
䠉1100mVCoO
Co-O-Co䠉 900
Co m etal
Co(OH) 2

0.4
0.3
|FT |

Intensity (arb. units)

1.5㻔b㻕

䠉 850
䠉 800
䠉 750
䠉 700
䠉 600
䠉 400

0.2
0.1

Co-N
Co-O

07710

7720 7730 7740 7750 7760 7770
Photon Energy (eV)

012R(A)34

ᅗ 4. CoPPyC ࡢ Co K ྾཰➃
㻔a㻕XANES ࢫ࣌ࢡࢺࣝࡢ㟁఩౫Ꮡᛶ࡜㻔b㻕Co ࿘ࡾࡢືᚄศᕸ㛵ᩘࡢ㟁఩౫Ꮡᛶ௒ᚋࡢㄢ㢟㸸௒ᅇヨࡳࡓ in situᐃ࡟࠾࠸࡚௨ୗࡢ 3 ࡘࡢၥ㢟ࡀⓎ⏕ࡋࡓࡓࡵࠊࡇࢀࡽࢆゎỴࡋḟࡢᐇ㦂࡟⮫ࡴࠋ
1㸬◲㓟ฎ⌮ࡋࡓ CoPPyC ࡢ in situᐃ࡟࠾࠸࡚ࠊࢭࣝ࡟ྵࡲࢀࡿ㕲ࡢᖸ΅ࡀ࠶ࡗࡓࡓࡵࠊ㕲ࢆྵࡲ࡞࠸ࢭࣝࡢస〇࡟ྲྀࡾ⤌ࡴࠋ2㸬CoPPyC ࡢ in situᐃ࡟࠾࠸࡚ࠊ㟁ᴟࡢ CoPPyC 㔞ࡀᑡ࡞ࡃ࢚ࢵࢪࢪࣕࣥࣉࡀᑠࡉ࠿ࡗࡓࡓࡵࠊヨᩱࡢቑ㔞࡟ྲྀࡾ⤌ࡴࠋ
3㸬࢝࢘ࣥࢱ࣮ഃ࠿ࡽᅗ 2 ࡢ཯ᛂᘧࡢࡼ࠺࡟㓟⣲ࡀⓎ⏕ࡋࣀ࢖ࢬࡢཎᅉ࡜࡞ࡗࡓࠋᑐ⟇࡜ࡋ࡚ࠊ࢝࢘ࣥࢱ࣮ࡢ㓄⨨ࡸᙧ≧ࡢኚ᭦ࢆ᳨ウࡍࡿࠋཧ⪃ᩥ⊩㸸[1] K. Asazawa, K. Yamada, H. Tanaka, A. Oka, M. Taniguchi, T. Kobayashi, Angew. Chem. Int. Ed. 46
㻔2007㻕 8024–8027.
[2] す⏿࡯࠿ࠊᖹᡂ 21 ᖺᗘ SPring-8 㔜Ⅼ⏘ᴗ฼⏝ㄢ㢟ᡂᯝሗ࿌᭩ 2009A1938.