Carbon-supported bimetallic PdIr catalysts for ethanol oxidation in alkaline media
Carbon-supported bimetallic PdIr catalysts for ethanol oxidation in alkaline media
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DOI：
10.1016/j.electacta.2010.09.018
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发表时间：
2010-12
影响因子：
6.6
通讯作者：
S. Shen;T. Zhao;Jianbo Xu
中科院分区：
文献类型：
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作者：
S. Shen;T. Zhao;Jianbo Xu
以NaBH 4为还原剂，柠檬酸盐为络合剂和稳定剂，采用同时还原法制备了碳载PdIr催化剂。采用X射线衍射、透射电子显微镜和X射线光电子能谱对不同Pd/Ir原子比的PdIr/C催化剂进行了表征。采用循环伏安法、线性扫描伏安法和计时电位法考察了PdIr/C催化剂在碱性介质中对乙醇氧化的催化活性和稳定性，并与Pd/C催化剂进行了比较。结果表明，在碱性介质中，Ir的加入显著提高了Pd催化剂上乙醇氧化的动力学性能，其中Pd 7Ir/C催化剂的活性和稳定性最高。催化性能的改善归因于这样的事实，即Ir除了Pd可以促进吸附的乙氧基中间体的去除，因为羟基基团更容易吸附在金属Ir和氧化铱（IrO 2）在较低的电位。
Carbon-supported bimetallic PdIr catalysts are synthesized by the simultaneous reduction method using NaBH4as reductant and citrate as complexing agent and stabilizer. X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy are used to characterize the PdIr/C catalysts with different Pd/Ir atomic ratios. The catalytic activity and stability of the PdIr/C catalysts for ethanol oxidation in alkaline media are examined and compared with that of the Pd/C catalyst by cyclic voltammetry, linear sweep voltammetry and chronopotentiometry. Results show that Ir addition can significantly improve the ethanol oxidation kinetics on Pd in alkaline media, and the Pd7Ir/C catalyst exhibits the highest activity and stability than the other samples do. The improvement in catalytic performance is attributed to the fact that Ir addition to Pd can facilitate the removal of adsorbed ethoxi intermediates, as the hydroxyl groups are more easily adsorbed on metallic Ir and iridium oxide (IrO2) at lower potentials.