催化学报 ›› 2025, Vol. 69: 303-314.DOI: 10.1016/S1872-2067(24)60205-6

• 论文 • 上一篇    下一篇

高密度Au-OV协同位点促进串联光催化CO2加氢制CH3OH

李兴娟a, 郭昱昊b, 管勤辉b, 李晓a, 张璐璐a, 冉维广a, 李娜a,*(), 颜廷江a,b,*()   

  1. a曲阜师范大学化学与化工学院, 山东省高校催化转化与清洁能源重点实验室, 山东曲阜 273165
    b陕西科技大学化学与化工学院, 陕西西安 710021
  • 收稿日期:2024-10-22 接受日期:2024-11-22 出版日期:2025-02-18 发布日期:2025-02-10
  • 通讯作者: 电子信箱: lina20201130@163.com (李娜), tingjiangn@163.com (颜廷江).
  • 基金资助:
    国家自然科学基金(22172086);国家自然科学基金(22105117);山东省泰山学者人才项目(tsqn202103064);山东省自然科学重大基础研究项目(ZR2021ZD06);山东省自然科学基金项目(ZR2021QB041);山东省自然科学基金项目(ZR2020QE053)

High-density Au-OV synergistic sites boost tandem photocatalysis for CO2 hydrogenation to CH3OH

Xingjuan Lia, Yuhao Guob, Qinhui Guanb, Xiao Lia, Lulu Zhanga, Weiguang Rana, Na Lia,*(), Tingjiang Yana,b,*()   

  1. aKey Laboratory of Catalytic Conversion and Clean Energy in Universities of Shandong Province, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, Shandong, China
    bCollege of Chemistry and Chemical Engineering, Shaanxi University of Science and Technology, Xi’an 710021, Shannxi, China
  • Received:2024-10-22 Accepted:2024-11-22 Online:2025-02-18 Published:2025-02-10
  • Contact: E-mail: lina20201130@163.com (N. Li), tingjiangn@163.com (T. Yan).
  • Supported by:
    National Natural Science Foundation of China(22172086);National Natural Science Foundation of China(22105117);Taishan Scholars Program of Shandong Province(tsqn202103064);Major Basic Research Project of Shandong Province(ZR2021ZD06);Natural Science Foundation of Shandong Province(ZR2021QB041);Natural Science Foundation of Shandong Province(ZR2020QE053)

摘要:

近年来, CO2大量排放带来了一系列环境问题, 资源化利用CO2来开展绿色减碳排放是一项紧迫任务. 利用光催化将CO2转化为有价值的化学物质, 如一氧化碳(CO)、甲烷(CH4)、甲醇(CH3OH), 甚至C2+产品, 是解决能源短缺和减少CO2排放的理想途径. 然而, 传统的单一半导体催化剂通常仅有单一活性位点, 存在光生电子-空穴对的快速复合和反应产物选择性差等问题. 因此, 为了高效、高选择性地实现光催化CO2还原反应, 有必要设计一种具有多个活性位点协同作用的催化剂.

本文首先利用钼粉、乙醇和H2O2为原料在溶剂热条件下合成出三氧化钼(MoO3), 然后将其在还原气氛中煅烧处理制备出富含氧空位的氧化钼(MoO3-x和MoO2), 进一步通过光沉积技术在三种氧化钼表面负载金纳米颗粒, 最终得到了用于光催化CO2加氢反应的催化剂(Au/MoO3, Au/MoO3-x和Au/MoO2). 光催化实验结果表明, Au/MoO2催化剂在光催化CO2加氢反应中产生的CH3OH产物的产率呈现递增的趋势, CH3OH的生成来自于另一产物CO的加氢反应. X射线粉末衍射、扫描电镜和高分辨透射电镜等结果表明, 相比MoO3和MoO3-x, 氧空位浓度最高的MoO2更利于Au纳米颗粒的锚定和均匀负载, 金属-氧化物界面作用更强. 光电流响应和阻抗图谱等结果表明, Au/MoO2催化剂界面形成的肖特基结, 显著提高了光生载流子的传输和分离效率. CO2和H2程序升温脱附结果表明, Au/MoO2催化剂上的CO2和H2吸附活化能力强于Au/MoO3和Au/MoO3-x催化剂. 原位红外实验表明, Au/MoO2催化剂上CO2经HCOO*和HCO3*中间体加氢生成甲醇, 且Au/MoO2催化剂上的HCOO*和HCO3*物种浓度显著高于其它催化剂. 由于MoO2具有丰富的氧空位, 更容易吸附和活化CO2分子; Au位点的存在促进了H2解离并增加了*H覆盖率, 使其提供大量的H原子更易与吸附在Mo位点上的CO2结合形成吸附中间体*CO或CO. Au/MoO2催化剂中的Au和MoO2之间建立的强界面相互作用, 有利于CO在Mo位点上的吸附并进一步实现串联反应合成甲醇.

综上所述, 本文系统研究了Au负载不同氧空位浓度的MoOx催化剂的结构对光催化CO2还原产物的影响规律, 揭示了氧空位和Au纳米颗粒协同促进串联光催化CO2加氢制甲醇的反应机理, 为设计具有多种活性位点协同串联机制的光催化CO2还原催化剂提供了一种新思路.

关键词: CO2加氢, 串联催化, 甲醇, Au/MoO2, 光催化

Abstract:

The production of renewable methanol (CH3OH) via the photocatalytic hydrogenation of CO2 is an ideal method to ameliorate energy shortages and mitigate CO2 emissions: however, the highly selective synthesis of methanol at atmospheric pressure remains challenging owing to the competing reverse water-gas shift (RWGS) reaction. Herein, we present a novel approach for the synthesis of CH3OH via photocatalytic CO2 hydrogenation using a catalyst featuring highly dispersed Au nanoparticles loaded on oxygen vacancy (OV)-rich molybdenum dioxide (MoO2), resulting in a remarkable selectivity of 43.78%. The active sites in the Au/MoO2 catalyst are high-density Au-oxygen vacancies, which synergistically promote the tandem methanol synthesis via an initial RWGS reaction and subsequent CO hydrogenation. This work provides comprehensive insights into the design of metal-vacancy synergistic sites for the highly selective photocatalytic hydrogenation of CO2 to CH3OH.

Key words: CO2 hydrogenation, Tandem catalysis, Methanol, Au/MoO2, Photocatalysis