物理化学学报 >> 2015, Vol. 31 >> Issue (12): 2341-2348.doi: 10.3866/PKU.WHXB201510151

催化和表面科学 上一篇    下一篇

Ag/Ag2WO4等离子体共振催化剂可见光催化还原CO2

何志桥,童丽丽,张志鹏,陈建孟,宋爽*()   

  • 收稿日期:2015-07-31 发布日期:2015-12-04
  • 通讯作者: 宋爽 E-mail:ss@zjut.edu.cn
  • 基金资助:
    国家自然科学基金(21477117, 21177115);浙江省自然科学基金杰出青年项目(LR13B070002, LR14E080001)

Ag/Ag2WO4 Plasmonic Catalyst for Photocatalytic Reduction of CO2 under Visible Light

Zhi-Qiao. HE,Li-Li. TONG,Zhi-Peng. ZHANG,Jian-Meng. CHEN,Shuang. SONG*()   

  • Received:2015-07-31 Published:2015-12-04
  • Contact: Shuang. SONG E-mail:ss@zjut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21477117, 21177115);Zhejiang Provincial Natural ScienceFoundation of China(LR13B070002, LR14E080001)

摘要:

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.

关键词: 光催化, 二氧化碳还原, 甲烷, 钨酸银, 局域表面等离子共振

Abstract:

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.

Key words: Photolysis, Carbon dioxide reduction, Methane, Silver tungstate, Localized surface plasma resonance

MSC2000: 

  • O643