Engineering sulfur vacancies for boosting electrocatalytic reactions

Transition metal sulfides are demonstrated to play an increasingly important role in boosting the deployment of ecofriendly electrocatalytic energy conversion technologies. It is also widely recognized that the introduction of vacancies is now becoming an important and valid approach to promote the electrocatalytic performance. In this review, the significance of sulfur vacancies on the enhancement of catalytic performance via four main functionalities, including tuning the electronic structure, tailoring the active sites, improving the electrical conductivity, and regulating surface reconstruction, is comprehensively summarized. Many effective strategies for the sulfur vacancy engineering, such as plasma treatment, heteroatom doping, and chemical reduction are also comprehensively provided. Subsequently, recent achievements in sulfur vacancy fabrication on various hotspot electrocatalytic reactions are also systematically discussed. Finally, a summary of the recent progress and challenges of this interesting field are organized, which hopes to guide the future development of more efficient metal sulfide electrocatalysts.