Scanning electrochemical microscopy characterization of bimetallic Pt–M (M = Pd, Ru, Ir) catalysts for hydrogen oxidation
Scanning electrochemical microscopy characterization of bimetallic Pt–M (M = Pd, Ru, Ir) catalysts for hydrogen oxidation
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DOI：
10.1016/j.electacta.2010.12.029
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发表时间：
2011-02
影响因子：
6.6
通讯作者：
Yu-Ching Weng;Cheng-Tse Hsieh
中科院分区：
文献类型：
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作者：
Yu-Ching Weng;Cheng-Tse Hsieh
采用尖端-生成-底物-收集(TG-SC)模式的组合筛选方法和扫描电化学显微镜(SECM)相结合的方法，系统、快速地鉴定了氢氧化反应(HOR)潜在的双金属催化剂(PtM，M=Pd，Ru，Ir)。在电极尖端靠近衬底的循环伏安扫描过程中，进一步考察了氢在候选催化剂上的催化氧化。通过与理论模型的拟合，从SECM逼近曲线确定了不同衬底电位下候选衬底上氢氧化的定量速率。SECM筛选结果表明，Pt4Pd6、Pt9Ru1和Pt3Ir7是铂-钯、铂-Ru和铂-Ir双金属系氢传感器催化剂的最佳组成。候选催化剂在HOR中的催化活性高度依赖于底物电位。获得了Pt4Pd6(Tafel斜率=124 mV，k°=0.19 cm/S，α=0.52)、Pt9Ru1(Tafel斜率=140 mV，k°=0.08 cm/S，α=0.58)和Pt3Ir7(Tafel斜率=114 mV，k°=0.11 cm/S，α=0.48)的高放动力学参数，并与铂(Tafel斜率=118 mV，k°=0.17 cm/S，α=0.5)进行了比较。在所研究的双金属催化剂中，Pt4Pd6对HOR表现出最高的活性，在较宽的应用电位范围内具有较高的标准速率常数。
A combinatorial screening method, combined with scanning electrochemical microscopy (SECM) in a tip-generation–substrate-collection (TG–SC) mode, was applied to systematically and rapidly identify potential bimetallic catalysts (Pt–M, M=Pd, Ru, Ir) for the hydrogen oxidation reaction (HOR). The catalytic oxidation of hydrogen on the candidate catalysts was further examined during cyclic voltammetric scans of the substrate with a tip close to the substrate. The quantitative rate of hydrogen oxidation on the candidate substrates was determined for different substrate potentials from SECM approach curves by fitting to a theoretical model. SECM screening results revealed that Pt4Pd6, Pt9Ru1and Pt3Ir7were the optimum composition of the catalysts from the Pt–Pd, Pt–Ru and Pt–Ir bimetallic systems for hydrogen sensors. The catalytic activity of the candidate catalysts in HOR was highly dependent on the substrate potential. The kinetic parameters for HOR were obtained on Pt4Pd6(Tafel slope=124mV, k°=0.19cm/s, α=0.52), Pt9Ru1(Tafel slope=140mV, k°=0.08cm/s, α=0.58) and Pt3Ir7(Tafel slope=114mV, k°=0.11cm/s, α=0.48) and compared with Pt (Tafel slope=118mV, k°=0.17cm/s, α=0.5). Among the bimetallic catalysts studied, Pt4Pd6exhibited the highest activity toward HOR with a high standard rate constant value in a wide range of applied potentials.