成果報告書詳細
管理番号20140000000171
タイトル*平成25年度中間年報 固体高分子形燃料電池実用化推進技術開発 基盤技術開 定置用燃料電池システムの低コスト化のためのMEA高性能化 (高濃度CO耐性アノード触媒の開発)
公開日2015/11/25
報告書年度2013 - 2013
委託先名国立大学法人山梨大学 国立大学法人北海道大学 独立行政法人産業技術総合研究所 国立大学法人信州大学 学校法人工学院大学 国立大学法人東北大学
プロジェクト番号P10001
部署名新エネルギー部
和文要約
英文要約The objective of this project is to develop highly CO-tolerant anode catalysts operated with reformate containing 300 ppm CO at low relative humidity (RH) and high temperature (40% RH at 80°C or 30% RH at 90°C), in addition to the voltage loss < 20 mV under 500 ppm CO at high RH, as well as sufficient durability for the residential PEFCs. To obtain clues for improving the performances, the mechanisms for the CO-tolerance and the degradation will be analyzed.
1. We have succeeded in preparing Pt2Ru3/Sb-SnO2 and Pt2Ru3/C catalysts with nearly identical particle size and alloy composition. It was clarified by in-situ FTIR that the high CO-tolerance of Pt2Ru3/Sb-SnO2 was ascribed to a decrease in the bridge-type COad, keeping active sites for the H2 oxidation. It was also important to maintain the water content of MEA for the operation at low RH and high temperature in the presence of high concentration CO.
2. Carbon gels (CGs) supports with various structures were prepared to clarify how the structure of support affects the CO tolerance. We have succeeded in controlling the size and volume of mesopores of CGs as well as microstructures. Hokudai 18, Pt2Ru3/CG (Pt2Ru3 dispersed on CG with the surface area of 1800 m2/g), exhibited much higher CO tolerance than commercial catalyst.
3. We have developed combined anode catalysts of the Rh-porphyrins (CO oxidation catalysts) and Pt2Ru3/C catalysts. In order to suppress the adsorption of Rh-porphyrin on Pt2Ru3 surface, which decreases the H2 oxidation activity, we have designed new Rh-porphyrins by changing the ligand structure and preparation methods.
4. Composite electrocatalysts based on RuO2 nanosheets with Pt/C or Pt-Ru/C were synthesized and the H2 oxidation activities in the presence of CO were examined. When RuO2 nanosheets were added to Pt/C, the H2 oxidation current in the presence of 300 ppm CO (j300) increased, possibly due to a blocking effect of the nanosheet. The CO tolerance of RuO2-PtRu/C was comparable to PtRu/C and Pt2Ru3/C. The nanosheet composite catalysts showed enhanced durability compared to commercial catalyst.
5. A novel modeling technique was developed to investigate the stability of Pt-Ru alloys. Quantum calculations were carried out to estimate the binding energy of Pt-Ru alloys and successfully developed the correlation function to calculate a binding energy for any given conformations. The stability of Pt-Ru alloys clusters having 2 nm ‐ 3 nm in diameter were theoretically examined. We have found that Pt atoms prefer to locate at the particle surface at 60°C and 90°C.
6. To clarify the CO tolerant mechanism of Pt-Ru alloy nanoparticle catalyst, we investigated CO adsorption on the Pt-Ru alloy nanoparticle by first-principles calculation. We found that a CO molecule easily adsorbs on the Ru site preferentially, compared with Pt sites. In addition, a water dissociation reaction on the Pt-Ru alloy nanoparticles was found to be promoted by applying the anodic potential.
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