Issue 40, 2023

Discharging antibonding orbital electrons of 1T-MoS2 by S-rich treatment for promoting photocatalytic H2 evolution

Abstract

Compared with thermodynamically stable hexagonal MoS2 with semiconducting 2H phases (2H-MoS2), metastable trigonal and metallic 1T-MoS2 as a photocatalytic H2-evolution cocatalyst exhibits higher electronic conductivity and more available active S atoms. However, the S–Hads bond of 1T-MoS2 is still relatively weak, which is not beneficial to H adsorption for the interfacial H2-production reaction. To greatly enhance the H-adsorption ability of S sites in 1T-MoS2, in this paper, a H-adsorption regulation strategy by discharging antibonding orbital electrons is proposed to construct an S-enriched 1T-MoS2 cocatalyst (denoted as 1T-MoS2+x). Herein, the 1T-MoS2+x cocatalyst was first synthesized by a hydrazine hydrate-assisted one-step hydrothermal route and was then modified on a TiO2 surface via an ultrasound-assisted method to prepare a 1T-MoS2+x/TiO2 photocatalyst. Photocatalytic performance tests showed that the 1T-MoS2+x/TiO2 (5%) sample displayed optimal H2-evolution activity, which was 162.4, 15.3, and 5.1 times higher than that of TiO2, 2H-MoS2/TiO2 (5%), and 1T-MoS2/TiO2 (5%), respectively. A series of DFT calculations and characterization uncover that the enrichment of S in 1T-MoS2+x can induce electron redistribution to produce electron-deficient S(2−δ)−, leading to decreased antibonding-orbital occupancy, which increases the stability of S–Hads bonds and enhances the H-adsorption ability of S sites for rapid H2 production. This study proposes a fresh idea to increase the active-site efficiency of MoS2-based cocatalysts by the reasonable regulation of antibonding orbital occupation.

Graphical abstract: Discharging antibonding orbital electrons of 1T-MoS2 by S-rich treatment for promoting photocatalytic H2 evolution

Supplementary files

Article information

Article type
Paper
Submitted
17 Aug 2023
Accepted
20 Sep 2023
First published
21 Sep 2023

J. Mater. Chem. A, 2023,11, 21874-21883

Discharging antibonding orbital electrons of 1T-MoS2 by S-rich treatment for promoting photocatalytic H2 evolution

P. Deng, D. Gao, P. Wang, X. Wang, F. Chen and H. Yu, J. Mater. Chem. A, 2023, 11, 21874 DOI: 10.1039/D3TA04934E

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