Electrochemical activity and stability of dealloyed Pt–Cu and Pt–Cu–Co electrocatalysts for the oxygen reduction reaction (ORR)
Electrochemical activity and stability of dealloyed Pt–Cu and Pt–Cu–Co electrocatalysts for the oxygen reduction reaction (ORR)
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DOI：
10.1016/j.jpowsour.2008.10.062
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发表时间：
2009-01
影响因子：
9.2
通讯作者：
K. Neyerlin;Ratndeep Srivastava;Chengfei Yu;P. Strasser
中科院分区：
文献类型：
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作者：
K. Neyerlin;Ratndeep Srivastava;Chengfei Yu;P. Strasser
对Pt 25 Cu 75和Pt 20 Cu 20 Co 60合金纳米颗粒电催化剂在液体电解质半电池环境中的电化学稳定性进行了比较研究。上述催化剂显示出相对于市售纯Pt电催化剂在电压循环期间具有改善的电化学表面积（ECSA）损失抗性。ECSA损失的差异归因于它们的初始平均粒度，其根据制备合金催化剂的温度（例如600、800和950°C）而变化。较高的制备温度导致较大的颗粒，并导致较低的ECSA损失。液体电解质环境短期耐久性测试（5000电压循环）揭示了添加钴是有益的，因为三元组合物表现出优于二元催化剂的稳定性优势。然后对膜电极组件（MEA）中的Pt 25 Cu 75和Pt 20 Cu 20 Co 60合金催化剂进行氧还原反应（ORR）活性和催化剂稳定性测试。在相对于可逆氢电极（RHE）从0.5至1.0V的30，000个电压循环之前和结束时获得的ORR活性数据显示，Pt 25 Cu 75和Pt 20 Cu 20 Co 60都能够保持它们相对于Pt/C的质量和基于Pt表面积的活性优势[R. Srivastava，P. Mani，N.作者声明：John W. 46（2007），8988; P. Mani，R. Srivastava，P. Strasser，J.Phys.Chem.C112（2008），2770; S. Koh，P. Strasser，J. Am. 129（2007），12624]。进一步的分析表明，在0.9V vs. RHE下测量的市售Pt催化剂的Pt表面积活性，以及Pt 25 Cu 75和Pt 20 Cu 20 Co 60的活性，每1000个电压循环增加数十μAcmPt− 2。这种比活度的增加与ECSA损失的减少相结合，导致在950°C下退火的Pt 25 Cu 75合金的Pt质量基活度的变化可以忽略不计。
A comparative study of the electrochemical stability of Pt25Cu75and Pt20Cu20Co60alloy nanoparticle electrocatalysts in liquid electrolyte half-cell environment was conducted. The aforementioned catalysts were shown to possess improved resistance to electrochemical surface area (ECSA) loss during voltage cycling relative to commercially available pure Pt electrocatalysts. The difference in ECSA loss was attributed to their initial mean particle size, which varied depending on the temperature at which the alloy catalysts were prepared (e.g. 600, 800 and 950°C). Higher preparation temperatures resulted in larger particles and lead to lower ECSA loss. Liquid electrolyte environment short-term durability testing (5000 voltages cycles) revealed the addition of cobalt to be beneficial as ternary compositions exhibited stability advantages over binary catalysts. Oxygen reduction reaction (ORR) activity and catalyst stability tests were then performed for both Pt25Cu75and Pt20Cu20Co60alloy catalysts in membrane electrode assemblies (MEA). ORR activity data, taken both prior to and at the conclusion of 30,000 voltage cycles from 0.5 to 1.0V vs. reversible hydrogen electrode (RHE), revealed that both Pt25Cu75and Pt20Cu20Co60were able to retain both their mass and Pt surface area-based activity advantage relative to Pt/C [R. Srivastava, P. Mani, N. Hahn, P. Strasser, Angew. Chem. Int. Ed. 46 (2007), 8988; P. Mani, R. Srivastava, P. Strasser, J. Phys. Chem. C 112 (2008), 2770; S. Koh, P. Strasser, J. Am. Chem. Soc. 129 (2007), 12624]. Further analysis revealed that the Pt surface area-based activity, measured at 0.9V vs. RHE, of commercially available Pt catalysts, as well as that for both Pt25Cu75and Pt20Cu20Co60increased on the order of tens of μAcmPt−2per 1000 voltage cycles. This increase in specific activity combined with a reduced ECSA loss resulted in a negligible change for the Pt mass-based activity of Pt25Cu75alloys annealed at 950°C.