Cu2O/SrTi1- xCrxO3 Heterojunction Photocatalyst for the Efficient Degradation of Isopropanol under Visible Light Irradiation

Zhonghua Li; Xuefan Zhang; Ping Chen; Zihan Shen; Rui Wang; Qiya He; Shuo Zhang; Shaozhong Chang; Jiaming Tian; Huigang Zhang

doi:10.1021/acs.langmuir.2c02007

Cu₂O/SrTi_{1- x}Cr_xO₃ Heterojunction Photocatalyst for the Efficient Degradation of Isopropanol under Visible Light Irradiation

Langmuir. 2022 Nov 15;38(45):13841-13848. doi: 10.1021/acs.langmuir.2c02007. Epub 2022 Nov 3.

Authors

Zhonghua Li^{1

2}, Xuefan Zhang¹, Ping Chen¹, Zihan Shen³, Rui Wang³, Qiya He^{2

3}, Shuo Zhang¹, Shaozhong Chang¹, Jiaming Tian¹, Huigang Zhang^{1

2

3}

Affiliations

¹ National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, College of Engineering and Applied Sciences, Nanjing University, Nanjing210093, China.
² Department of Chemical Engineering, Northwest University, Xi'an710069, China.
³ State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing100190, China.

PMID: 36325981
DOI: 10.1021/acs.langmuir.2c02007

Abstract

A heterojunction of Cu₂O and Cr-doped SrTiO₃ (SrTi_1-xCr_xO₃) was designed for selective photocatalytic isopropanol (IPA) oxidation under visible light irradiation. The photocatalytic oxidation of IPA was measured in a fixed-bed reactor. Cr dopants can increase the light absorption and improve the activity of the catalyst. The formation of the Cu₂O/SrTi_1-xCr_xO₃ heterojunction can further broaden the absorption range of lights and dramatically increase the photocatalytic activity for selective oxidation of IPA. The 3% Cu₂O/SrTi_0.99Cr_0.01O₃ catalyst can fully convert ∼1000 ppm IPA under illumination in 2 h. The selectivity of acetone is ∼100%. The yield is 83 and 4 times higher than that using SrTiO₃ and SrTi_0.99Cr_0.01O₃ as catalysts, respectively. By measuring the ultraviolet-visible absorption spectra and Mott-Schottky plots, we obtained the band structure of the heterojunction, which shows that the conduction and valence bands of Cu₂O are higher than those of SrTi_1-xCr_xO₃, therefore facilitating the separation and transfer of photogenerated electrons and holes. In addition, electron paramagnetic resonance spectroscopy and radical trapping tests reveal that the generation of hydroxyl and superoxide leads to photocatalytic oxidation of IPA by the heterojunction photocatalyst.