%0 Journal Article
%T <br>
%A 何志桥
%A 宋爽
%A 张志鹏
%A 童丽丽
%A 陈建孟
%J 物理化学学报
%D 2015
%R 10.3866/PKU.WHXB201510151
%X 转化CO2为有机组分是缓解全球变暖和保障持续能源供给的有效方法之一.采用简易的离子交换结合水合肼还原法制备了一系列不同晶相Ag2WO4载银(Ag/Ag2WO4)的等离子共振光催化剂,并用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜-能量色散X射线光谱(SEM-EDS)、紫外-可见(UV-Vis)吸收光谱和比表面积测试对催化剂进行了表征.较之Ag2WO4, Ag/Ag2WO4在可见光催化还原CO2生成CH4时显示了明显提高的量子产率(QY)、能量投入产出比(EROEI)、转换数(TON),就Ag/α-Ag2WO4, Ag/β-Ag2WO4和Ag/γ-Ag2WO4而言,最佳催化剂为Ag/β-Ag2WO4,其实际最佳Ag:Ag2WO4摩尔比为4:96,该催化剂还原CO2为CH4的QY、EROEI、TON和拟一级反应速率常数分别为0.145%、0.067%、9.61和1.96×10-6 min-1.此外,制备的等离子共振Ag/Ag2WO4光催化剂在可见光辐照下进行循环反应仍能保持稳定性.局域表面等离子共振效应是强化Ag/Ag2WO4光催化剂活性和稳定性的主要原因.<br>The conversion of CO2 into organic compounds is a promising method to mitigate global warming and assist in sustaining energy resources. A series of plasmonic photocatalysts, comprised of Ag supported on Ag2WO4 (Ag/Ag2WO4) with different crystalline phases, are fabricated by a facile ion-exchange method and subsequent reduction with hydrazine hydrate. The catalysts are characterized using X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), UV-Vis absorption spectroscopy, and Brunauer-Emmett-Teller analyses. Compared with Ag2WO4, the Ag/Ag2WO4 exhibits a markedly improved quantum yield (QY), energy returned on energy invested (EROEI), and turnover number (TON) for CO2 reduction to CH4 under visible-light irradiation. Among Ag/α-Ag2WO4, Ag/β-Ag2WO4, and Ag/γ-Ag2WO4 catalysts, the highest activity for CO2 photoreduction to CH4 is obtained for Ag/β-Ag2WO4 with an actual molar composition of 4% Ag and 96% Ag2WO4. Correspondingly the QY, EROEI, TON, and pseudo first-order rate constant are 0.145%, 0.067%, 9.61, and 1.96×10-6 min-1, respectively. Moreover, the plasmonic Ag/Ag2WO4 photocatalysts are stable after repeated reaction cycles under visible-light irradiation. It is proposed that the localized surface plasma resonance effect of surfacedeposited Ag contributed to the enhanced activities and stabilities of the Ag/Ag2WO4 photocatalysts
%U http://www.whxb.pku.edu.cn/CN/Y2015/V31/I12/2341