催化学报 ›› 2023, Vol. 46: 113-124.DOI: 10.1016/S1872-2067(22)64175-5

• 论文 • 上一篇    下一篇

通过实验和理论验证Pt0/SrTiO3‒δ复合催化剂双反应路径促进CO2还原

李卓根a, 张伟斌b, 朱陆军a, 高健智a, 石先进c, 黄宇c, 刘鹏a, 朱刚强a,*()   

  1. a陕西师范大学物理与信息技术学院, 陕西西安 710062
    b云南师范大学物理和电子信息学院, 云南昆明 650500
    c中国科学院地球环境研究所黄土与第四纪地质国家重点实验室, 陕西西安 710061
  • 收稿日期:2022-09-20 接受日期:2022-10-08 出版日期:2023-03-18 发布日期:2023-02-21
  • 通讯作者: *电子信箱: zgq2006@snnu.edu.cn.
  • 基金资助:
    国家自然科学基金(52072230);国家自然科学基金(51772183);榆林市科技计划项目(CXY-2020-040)

Promotion of dual-reaction pathway in CO2 reduction over Pt0/SrTiO3‒δ: Experimental and theoretical verification

Zhuogen Lia, Qadeer Ul Hassana, Weibin Zhangb, Lujun Zhua, Jianzhi Gaoa, Xianjin Shic, Yu Huangc, Peng Liua, Gangqiang Zhua,*()   

  1. aSchool of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, Shaanxi, China
    bInstitute of Physics and Electronic Information, Yunnan Normal University, Kunming 650500, Yunnan, China
    cState Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, Shaanxi, China
  • Received:2022-09-20 Accepted:2022-10-08 Online:2023-03-18 Published:2023-02-21
  • Contact: *E-mail: zgq2006@snnu.edu.cn (G. Zhu).
  • Supported by:
    National Natural Science Foundation of China(52072230);National Natural Science Foundation of China(51772183);The YuLin Science and Technology Project(CXY-2020-040)

摘要:

在以H2O为质子源的光催化二氧化碳还原反应(CO2RR)过程中, 光解H2O产氢气(H2)被认为是一个竞争反应.  因此, 光催化CO2RR过程需要抑制H2的产生, 以提高碳氢产物的选择性和产率.  以CO2和H2为反应物的逆水气变换反应(RWGS)是常见的CO2加氢反应, 在较高的温度和催化剂作用下生成CO和H2O.  目前, 光催化CO2RR研究主要聚焦于产物的选择性, 而有关光解H2O产生的还原性气体H2在光热效应的促进下成为CO2RR中新的质子源研究较少.  光热催化是一种新的高效催化反应方式, 在反应过程中需要光照和加热.  光照能够促进半导体光生载流子的激发, 热效应则能降低反应物分子的活化势垒, 并能够促进中间产物的表面迁移以及生成物的脱附.  利用光热催化热力学和动力学上的有利条件, 为以H2O为质子源的光热催化CO2RR中RWGS反应提供了H2源以及所需的能量.  

本文合成了具有强电子转移能力、高热稳定性和化学稳定性的Pt纳米颗粒(NPs)负载在具有丰富氧空位(OVs)的SrTiO3‒δ纳米片, 形成金属-半导体相互作用的Pt-OVs-STO纳米复合催化剂, 并利用该纳米复合催化剂系统地研究了以H2O为质子源的光热催化CO2RR的反应路径.  结合X射线粉末衍射、X射线光电子能谱、高角度环形暗场和明场球差校正扫描电子显微镜、电子顺磁共振和紫外可见吸收光谱等表征手段, 研究了表面负载的Pt0 NPs与SrTiO3‒δ之间的相互作用.  这种金属-半导体之间的强相互作用和独特的电子结构促进了复合半导体结构的光吸收能力, 提升了光生载流子的分离以及对反应物分子的吸附.  由H2O分解产生的H2能够有效地促进在Pt-OVs-STO纳米复合结构的双路径CO2还原反应: CO2直接质子化和RWGS反应.  DFT理论计算结果表明, 该纳米复合结构能够有效地促进半导体表面电荷转移和H2生成, 并且降低RWGS反应和CO2质子化的反应势垒.  综上, 本文阐明了在H2O为质子源的光热催化CO2RR中Pt0/SrTiO3‒δ纳米复合结构上光解H2O产生的H2和RWGS反应之间的关系, 并为后续的CO2RR的研究提供了新视角.  

关键词: 光热催化, 析氢反应, 逆水煤气反应, 钙钛矿, 金属-半导体相互作用

Abstract:

The H2 evolution is generally considered a competing reaction in photocatalytic CO2 reduction reaction (CO2RR) using H2O as the proton source. However, the reducing gas H2 generated from H2O splitting can be the proton source in CO2RR under the enhanced dynamic role of the thermal effect. The reverse water gas shift (RWGS) reaction, a CO2 hydrogenation reaction, should occur in photothermal environment owing to thermodynamically and kinetically favorable. Herein, nanostructured metal-semiconductor contact consisting of Pt nanoparticles (NPs) supported on SrTiO3‒δ nanosheets with rich oxygen vacancies (Pt-OVs-STO) was constructed for investigating its feasibility and efficiency in the RWGS reaction under photothermal effect. Our experimental results substantiate that the H2 generated by H2O splitting effectively contributes to the RWGS reaction over Pt-OVs-STO system. The Pt0 NPs not only efficiently facilitate surface charge transfer, but also lower the energy barrier of the O‒H bond breaking, H2 releasing, and RWGS reaction, thereby showing an outstanding CO2RR performance. The strong interaction between the Pt0 NPs and SrTiO3‒δ has been extensively demonstrated by a series of experimental characterizations and density functional theory calculations. This work elucidates the relation between H2 evolution and RWGS reaction over Pt0/SrTiO3‒δ structure in photothermal catalytic CO2RR using H2O as the proton source and provides new perspectives for subsequent CO2RR.

Key words: Photothermal catalysis, H2 evolution, Reverse water gas shift reaction, Perovskite, Metal-semiconductor interaction