Particle Size Effects in the Catalytic Electroreduction of CO2 on Cu Nanoparticles
Particle Size Effects in the Catalytic Electroreduction of CO2 on Cu Nanoparticles
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DOI：
10.1021/ja500328k
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发表时间：
2014-05-14
影响因子：
15
通讯作者：
Strasser, Peter
中科院分区：
文献类型：
--
作者：
Reske, Rulle;Mistry, Hemma;Strasser, Peter
研究了可控尺寸铜纳米颗粒（NPs）在CO2催化电还原过程中的粒径效应。制备了平均粒径在2 ~ 15 nm范围内的Cu NP催化剂，分析了其在CO2电还原过程中的催化活性和选择性，并与块状Cu电极进行了比较。随着Cu颗粒尺寸的减小，对H-2和CO的催化活性和选择性显著增加，特别是对于小于5 nm的NPs。纳米级Cu表面对碳氢化合物（甲烷和乙烯）的选择性越来越低。利用模型球形铜粒子表面原子配位的尺寸依赖性对实验结果进行了合理化分析。低配位表面位点数量的变化及其更强的化学吸附性与H-2和CO选择性的提高、更高的催化活性和更小的碳氢化合物选择性有关。所提出的活性-选择性-尺寸关系为纳米级表面上的CO2电还原反应提供了新的见解。我们最小的纳米颗粒（约2纳米）进入从头计算可获得的尺寸范围，因此，所得结果很好地用于密度泛函理论（DFT）评估和反应机理验证。
A study of particle size effects during the catalytic CO2 electroreduction on size-controlled Cu nanoparticles (NPs) is presented. Cu NP catalysts in the 2-15 nm mean size range were prepared, and their catalytic activity and selectivity during CO2 electroreduction were analyzed and compared to a bulk Cu electrode. A dramatic increase in the catalytic activity and selectivity for H-2 and CO was observed with decreasing Cu particle size, in particular, for NPs below 5 nm. Hydrocarbon (methane and ethylene) selectivity was increasingly suppressed for nanoscale Cu surfaces. The size dependence of the surface atomic coordination of model spherical Cu particles was used to rationalize the experimental results. Changes in the population of low-coordinated surface sites and their stronger chemisorption were linked to surging H-2 and CO selectivities, higher catalytic activity, and smaller hydrocarbon selectivity. The presented activity-selectivity-size relations provide novel insights in the CO2 electroreduction reaction on nanoscale surfaces. Our smallest nanoparticles (similar to 2 nm) enter the ab initio computationally accessible size regime, and therefore, the results obtained lend themselves well to density functional theory (DFT) evaluation and reaction mechanism verification.