Opportunities and challenges in the electrocatalysis of CO2 and CO reduction using bifunctional surfaces: A theoretical and experimental study of Au-Cd alloys
Opportunities and challenges in the electrocatalysis of CO2 and CO reduction using bifunctional surfaces: A theoretical and experimental study of Au-Cd alloys
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DOI：
10.1016/j.jcat.2016.04.008
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发表时间：
2016-11-01
影响因子：
7.3
通讯作者：
Chorkendorff, Ib
中科院分区：
文献类型：
--
作者：
Jovanov, Zarko P.;Hansen, Heine A.;Chorkendorff, Ib
电解可以使二氧化碳大规模转化为燃料和小分子。这一观点讨论了对CO2和CO还原电催化的最新理解，并提供了迄今为止最有前途的方法的概述。受理论模型的启发，我们开始探索使用Au-Cd基合金的“双功能”催化剂。密度泛函理论计算表明，相对于Au上的相似值，在Au3Cd上的混合Au- cd位点上，CO2还原成CO和甲醇的热力学更有利。我们使用各种工具对合金体和表面进行了实验测试。研究发现，Au3Cd在中性介质中的CO析出活性低于Au，而Au- cd合金在碱性介质中的CO还原活性也可以忽略不计。这表明预测具有催化活性的混合CdAu位点不存在于样品中。催化性能与大块合金上的au端台阶表面最一致，可能是通过吸附质诱导重组形成的。我们强调，未来的双金属催化剂必须考虑由反应中间体引起的潜在依赖的表面重组效应。(C) 2016 Elsevier Inc.版权所有。
Electrolysis could enable the large-scale conversion of CO2 to fuels and small molecules. This perspective discusses the state-of-the-art understanding of CO2 and CO reduction electrocatalysis and provides an overview of the most promising approaches undertaken thus far. We set to explore "bifunctional" catalysts using Au-Cd based alloys inspired by theoretical modelling. Density functional theory calculations suggest more favourable thermodynamics for CO2 reduction to CO and methanol on mixed Au-Cd sites on Au3Cd relative to similar values on Au. We use various tools to test the bulk and surface alloys experimentally. We find that Au3Cd in neutral media exhibits lower CO evolution activity than Au, and Au-Cd alloys also show negligible activity for CO reduction in alkaline media. This indicates that the mixed CdAu sites predicted to be catalytically active are not present in the sample. The catalytic performance is most consistent with Au-terminated step surface on a bulk alloy, possibly formed through adsorbate induced restructuring. We highlight that future bimetallic catalysts must consider potential-dependent surface restructuring effects caused by reaction intermediates. (C) 2016 Elsevier Inc. All rights reserved.