Ultrathin 5-fold twinned sub-25 nm silver nanowires enable highly selective electroreduction of CO2 to CO
Ultrathin 5-fold twinned sub-25 nm silver nanowires enable highly selective electroreduction of CO2 to CO
复制标题
DOI：
10.1016/j.nanoen.2018.01.016
复制
发表时间：
2018-03-01
期刊：
影响因子：
17.6
通讯作者：
Luo, Jing-Li
中科院分区：
文献类型：
--
作者：
Liu, Subiao;Wang, Xian-Zong;Luo, Jing-Li
CO2的电化学还原（CO2 RR）具有通过合成碳中性燃料来对抗温室效应的潜力。因此，对于CO2 RR的贵金属催化剂的高效率对于减少贵金属的量是高度期望的。本文通过溴代物介导的多元醇法合成了直径小于25（D-25）和100 nm（D-100）的5重孪晶银纳米线（NW），并研究了其结构驱动的CO2 RR催化活性增强。与D-100 Ag纳米线和Ag纳米颗粒（NPs）相比，D-25 Ag纳米线具有显著提高的电流密度（j），以及在宽电位范围内显著增加的法拉第效率（FE）和能量效率（EE），最大值分别达到99.3%和61.3%。更重要的是，获得了引发CO2 RR的相当低的起始过电位（eta）和超过24 h的降解可忽略不计的稳定性，进一步验证了D-25 Ag纳米线对于CO2 RR的上级性能。密度泛函理论（DFT）计算结果表明，5倍孪晶Ag纳米线的催化活性提高主要是由于直径效应和长度效应导致的催化活性中心比例增加，以及5倍孪晶纳米结构完全被有利于CO2 RR的晶面所包围.
Electrochemical reduction of CO2 (CO2RR) holds the potential to battle the greenhouse effect through the synthesis of carbon-neutral fuels. The high efficiency of noble metal catalysts for CO2RR is, therefore, highly desirable to reduce the quantities of noble metals. We herein synthesized 5-fold twinned Ag nanowires (NWs) with diameters less than 25 (D-25) and 100 nm (D-100) through a facile bromide-mediated polyol method and subsequently, investigated their structure-driven enhanced catalytic activity for CO2RR. Compared with D-100 Ag NWs and Ag nanoparticles (NPs), D-25 Ag NWs possess remarkably enhanced current density (j), together with significantly increased Faraday efficiencies (FEs) and energy efficiencies (EEs) over a broad potential range and achieve their maximum values of 99.3% and 61.3%, respectively. More importantly, a quite low onset overpotential (eta) to initiate CO2RR and a stability with negligible degradation of over 24 h were obtained, further verifying the superior performance of D-25 Ag NWs for CO2RR. Density functional theory (DFT) calculations reveal that the improved catalytic activity over the ultrathin 5-fold twinned Ag NWs originates from the increased ratio of the catalytically active sites contributed by both diameter and length effects, and the special 5-fold twinned nanostructure completely enclosed by energetically favorable facets for CO2RR.