Bi selectively doped SrTiO3-x nanosheets enhance photocatalytic CO2 reduction under visible light

Longkai Pan; Hui Mei; Gangqiang Zhu; Shiping Li; Xiaoqian Xie; Siwen Gong; Hongxia Liu; Zhipeng Jin; Jianzhi Gao; Laifei Cheng; Litong Zhang

doi:10.1016/j.jcis.2021.12.033

Bi selectively doped SrTiO_3-x nanosheets enhance photocatalytic CO₂ reduction under visible light

J Colloid Interface Sci. 2022 Apr:611:137-148. doi: 10.1016/j.jcis.2021.12.033. Epub 2021 Dec 6.

Authors

Longkai Pan¹, Hui Mei², Gangqiang Zhu³, Shiping Li⁴, Xiaoqian Xie⁵, Siwen Gong⁵, Hongxia Liu¹, Zhipeng Jin¹, Jianzhi Gao⁵, Laifei Cheng¹, Litong Zhang¹

Affiliations

¹ Science and Technology on Thermostructural Composite Materials Laboratory, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072, China.
² Science and Technology on Thermostructural Composite Materials Laboratory, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072, China. Electronic address: meihui@nwpu.edu.cn.
³ School of Physics and Information Technology, Shaanxi Normal University, Xi' an, 710062, China. Electronic address: zgq2006@snnu.edu.cn.
⁴ Department of Physics and Oxide Research Center, Hankuk University of Foreign Studies, Yongin 17035, Republic of Korea.
⁵ School of Physics and Information Technology, Shaanxi Normal University, Xi' an, 710062, China.

PMID: 34942487
DOI: 10.1016/j.jcis.2021.12.033

Abstract

Converting CO₂ into chemical energy by using solar energy is an environmental strategy to achieve carbon neutrality. In this paper, two dimensionality (2D) SrTiO_3-x nanosheets with oxygen vacancies were synthesized successfully. Oxygen vacancies will generate defect levels in the band structure of SrTiO_3-x. So, SrTiO_3-x nanosheets have good photocatalytic CO₂ reduction performance under visible light. In order to further improve its photocatalytic efficiency, Bi was used to dope Sr site and Ti site in SrTiO_3-x nanosheets respectively. It is found that Sr site is the adsorption site of CO₂ molecules. When Bi replaced Sr, CO₂ adsorption on the surface of SrTiO_3-x nanosheets was weakened. When Bi replaced Ti, there has no effect on CO₂ adsorption. Due to the synergistic effect of Bi doping, oxygen vacancies, and Sr active site, the 1.0% Bi-doped Ti site in SrTiO_3-x (1.0% Bi-Ti-STO) had the best photocatalytic performance under visible light (λ ≥ 420 nm). CO and CH₄ yields were 5.58 umol/g/h and 0.36 umol/g/h. Photocatalytic CO₂ reduction path has always been the focus of exploration. The in-situ FTIR spectrum proved the step of photocatalytic CO₂ reduction and COO- and COOH are important intermediates in the photocatalytic CO₂ reaction.

Keywords: Active site; Bi doping; Intermediates; Oxygen vacancy; SrTiO(3-x) nanosheet.