S vacancies in 2D SnS2 accelerating hydrogen evolution reaction

• Published in: Science China materials 2022-07, Vol.65 (7), p.1833-1841
• Main Authors: Shao, Gonglei, Xiang, Haiyan, Huang, Mengjie, Zong, Yi, Luo, Jun, Feng, Yexin, Xue, Xiong-Xiong, Xu, Jie, Liu, Song, Zhou, Zhen
• Format: Article
• Language: English
• Subjects: Annealing; Basal plane; Charge density; Chemistry and Materials Science; Chemistry/Food Science; Hydrogen evolution reactions; Lattice vacancies; Materials Science; Surface charge; Tin; Tin disulfide; Two dimensional materials
• ISSN: 2095-8226; 2199-4501
• DOI: 10.1007/s40843-021-1991-6

Precise manipulation of atomic defects is essential for modulating the intrinsic properties of two-dimensional (2D) materials. In this study, sulfur (S) atoms are accurately knocked out in the 2D basal plane of pure tin disulfide (SnS 2 ). By varying the annealing temperatures (250–350°C), SnS 2 with different S vacancy concentrations (Vs−SnS 2 ) can be obtained. When SnS 2 is annealed at 350°C for 5 h, the S vacancies in the forms of single S atom and double S atoms could reach up to 30.5%. The Vs−SnS 2 is tested in the microelectrocatalytic hydrogen evolution reaction (HER). Vs−SnS 2 with S vacancies of 30.5% generates superior catalytic performance, with a Tafel slope of 74 mV dec −1 and onset potential of 141 mV. The mechanism has been proposed. First, computation confirms that the absence of S atoms prompts surface charge modulation and enhances electronic conductivity. In addition, the under-coordinated Sn atoms adjacent to S vacancy introduce the lattice distortion and charge density redistribution, which are beneficial to hydrogen binding in HER. In short, accurate knockout of specific atoms by controlling the annealing temperature is a promising strategy to explore structure-dependent properties of various 2D materials.