Insight into the promoting role of Rh doped on Pt(111) in methanol electro-oxidation
The bi-functional mechanism has been widely accepted for describing the binary catalysts in methanol electrooxidation,in which Pt sites can catalyze the methanol dehydrogenation and the second elements (e.g.Ru,Sn) can activate water to oxidants.However,in terms of binary PtRh,the surface Rh sites being identified not to be oxidized as easily as Ru,may participate in the dehydrogenation reaction at low potentials rather than just activate water.In this work,we investigate the roles of doped Rh on Pt(111) in methanol electrooxidation by density functional theory (DFT) calculations for the first time.We find that themethanol dehydrogenation activity is enhanced on Rh/Pt(111) because Rh can eliminate significantly the repulsive interaction between carbon fragment and H at the transition state.The formation potential of OH* on Rh/Pt(111) is 0.36 V (vs SHE) which is lower than 0.64 V (vs SHE) on Pt(111).Meantime,the coupling barrier between CO* and OH* is also decreased from 0.47 eV to 0.24 eV.By considering coverage,the individual Rh atom on surface is identified to be more effective than the neighbouring atoms for methanol electrooxidation,and thus a moderate Rh coverage is suggested.This work provides some insight into the binary catalysts for methanol electrooxidation.
Density functional theory Binary catalyst Electrocatalysis CO oxidation PtRh Dehydrogenation
Tian Sheng Shi-Gang Sun
Collaborative Innovation Center of Chemistry for Energy Materials,State Key Laboratory of Physical Chemistry of Solid Surfaces,Department of Chemistry,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China
国际会议
南京
英文
24-29
2016-12-23（万方平台首次上网日期，不代表论文的发表时间）