Rh@Pt内凹立方体核壳催化剂的制备及其乙醇电氧化性能

Synthesis of Rh@Pt/C Concave Cubic Core-Shell Catalyst and Its Ethanol Electro-Oxidation Performance

贵金属Rh基催化剂可有效催化乙醇中C―C键断裂,有利于实现乙醇完全电氧化,但Rh催化剂对乙醇电氧化的催化活性较低。本文通过种子介导生长法制备了具有内凹立方体形貌的Rh@Pt/C核壳催化剂,考察了不同Pt壳层厚度的Rh@Pt/C核壳催化剂在碱性介质中对乙醇电氧化反应(EOR)的催化性能。其中Rh@Pt0.25/C核壳催化剂对EOR的质量归一化电流最高为520 mA/mg,此时面积归一化电流也最高,为0.16 mA/cm^(2)。研究表明,Rh@Pt/C核壳催化剂中Rh和Pt之间的表面应变效应和电子配体效应取决于Rh表面Pt壳层的厚度,Pt壳层厚度的改变,可调控催化剂中Rh和Pt的协同作用,从而减弱毒性中间体对催化剂表面的吸附,优化催化剂对EOR的性能。总体上,Rh表面Pt壳层为3层的Rh@Pt0.25/C核壳催化剂表现出最优的EOR活性和稳定性,此时催化剂也兼具了较优的抗毒化能力。

The Rh-based catalyst can effectively catalyze the cleavage of the C―C bond in ethanol,which is beneficial for achieving complete electro-oxidation of ethanol.However,the catalytic activity of Rh catalyst for ethanol electro-oxidation is low.In this study,Rh@Pt/C core-shell catalysts with concave cubic morphology are prepared by seed-mediated growth method.The catalytic performance of Rh@Pt/C core-shell catalysts with different Pt shell thicknesses in alkaline medium for ethanol electro-oxidation reaction(EOR)is investigated.The Rh@Pt0.25/C core-shell catalyst has the highest mass normalized current for EOR of 520 mA/mg,and the area normalized current is also the highest at 0.16 mA/cm^(2).The study shows that the surface strain effect and electronic ligand effect between Rh and Pt in Rh@Pt/C core-shell catalysts depend on the thickness of Pt shell on Rh surface,and the change of Pt shell thickness can regulate the synergistic effect of Rh and Pt in the catalyst,thereby reducing the adsorption of toxic intermediates on the catalyst surface and optimizing the performance of the catalyst for EOR.Overall,Rh@Pt0.25/C core-shell catalyst with 3 layers of Pt shell on Rh surface exhibits the best EOR activity and stability,and the catalyst's resistance to poisoning is also excellent.