Oxygen vacancy enhanced photocatalytic activity of Cu2O/TiO2 heterojunction

Hong Qian; Binxia Yuan; Yuhao Liu; Rui Zhu; Weiling Luan; Chengxi Zhang

doi:10.1016/j.isci.2024.109578

Oxygen vacancy enhanced photocatalytic activity of Cu₂O/TiO₂ heterojunction

iScience. 2024 Mar 26;27(5):109578. doi: 10.1016/j.isci.2024.109578. eCollection 2024 May 17.

Authors

Hong Qian¹, Binxia Yuan^{1

2}, Yuhao Liu¹, Rui Zhu¹, Weiling Luan², Chengxi Zhang³

Affiliations

¹ College of Energy and Mechanical Engineering, Shanghai University of Electric Power, Shanghai 201306, P.R. China.
² School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China.
³ Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China.

Abstract

In this study, a method was developed to create oxygen vacancies in Cu₂O/TiO₂ heterojunctions. By varying the amounts of ethylenediaminetetraacetic acid (EDTA), sodium citrate, and copper acetate, Cu₂O/TiO₂ with different Cu ratios were synthesized. Tests on CO₂ photocatalytic reduction revealed that Cu₂O/TiO₂'s performance is influenced by Cu content. The ideal Cu mass fraction in Cu₂O/TiO₂, determined by inductively coupled plasma (ICP), is between 0.075% and 0.55%, with the highest CO yield being 10.22 μmol g^-1 h^-1, significantly surpassing pure TiO₂. High-resolution transmission electron microscopy and electron paramagnetic resonance studies showed optimal oxygen vacancy in the most effective heterojunction. Density functional theory (DFT) calculations indicated a 0.088 eV lower energy barrier for ∗CO₂ to ∗COOH conversion in Cu₂O/TiO₂ with oxygen vacancy compared to TiO₂, suggesting that oxygen vacancies enhance photocatalytic activity.

Keywords: Material chemistry; physical chemistry; surface chemistry.