Issue 20, 2023

A combined theoretical and experimental investigation on the photocatalytic hydrogenation of CO2 on Cu/ZnO polar surface

Abstract

The photocatalytic hydrogenation of CO2 by Cu-deposited ZnO (Cu/ZnO) polar surfaces is investigated through density functional theory (DFT) calculations combined with experimental work. The DFT results demonstrate that, without Cu-loading, CO2 and H2 present weak physisorption on the clean ZnO polar surface, except that H2 undergoes strong chemisorption on the ZnO(000[1 with combining macron]) surface. Cu deposition on the ZnO polar surface could remarkably enhance the CO2 chemisorption ability, due to the induced charge redistribution on the interface of the Cu/ZnO polar surface systems. Additionally, a Cu-nanoisland, which was simulated using a Cu(111) slab model, exhibited strong ability to chemically adsorb H2. Thus, H2 may act as an adsorption competitor to CO2 on the Cu/ZnO(000[1 with combining macron]), while, in contrast, CO2 and H2 (syngas) may have more opportunity to simultaneously adsorb on Cu/ZnO(0001) to promote the CO2 hydrogenation. These facet-dependent properties lead us to assume that Cu/ZnO(0001) should be a favorable photocatalyst for CO2 hydrogenation. This assumption is further verified by our photocatalysis experiment based on a ZnO single crystal. According to the theoretical and experimental results, the optimal HCOO* reaction pathway for the photocatalytic hydrogenation of CO2 on Cu/ZnO(0001) is proposed. In this optimal HCOO* path, the hydrogenation of CO2* step and hydrogenation of HCOO* step could be promoted by the coupling of a photo-generated spillover proton and a photoelectron on the interface of Cu/ZnO(0001). This research demonstrates the feasibility of the photocatalytic reduction of CO2 on Cu/ZnO(0001), and will help to develop related high-efficiency catalysts.

Graphical abstract: A combined theoretical and experimental investigation on the photocatalytic hydrogenation of CO2 on Cu/ZnO polar surface

Supplementary files

Article information

Article type
Paper
Submitted
03 mar. 2023
Accepted
21 apr. 2023
First published
21 apr. 2023

Nanoscale, 2023,15, 9040-9048

A combined theoretical and experimental investigation on the photocatalytic hydrogenation of CO2 on Cu/ZnO polar surface

H. Xiao, Y. Lian, S. Zhang, M. Zhang, J. Zhang and C. Li, Nanoscale, 2023, 15, 9040 DOI: 10.1039/D3NR01001E

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