Transition metal dichalcogenide catalysts incorporating hollow carbon spheres toward water splitting and supercapacitors

Abstract

Transition metal dichalcogenides (TMDs), e.g., MoS₂ and MoSe₂, are widely used as catalysts for electrochemical water splitting and green energy conversion because of their high stability and favorable hydrogen adsorption energies. However, their intrinsically low electrical conductivity and limited surface area often lead to poor hydrogen evolution reaction (HER) performance. The high conductivity and layered structure of hollow carbon spheres (HCSs) compensate for these shortcomings, thus combining TMDs with HCSs has been extensively investigated. In addition, non-metal dopants can be introduced into carbon frameworks to control the growth of hybrid TMD nanostructures and to increase electrochemical activity by creating additional active sites. This review first focuses on the development of N-, O-, and P-doped HCSs, reviewing synthesis routes, layer numbers, and performance metrics. It then highlights recent advances in integrating layered molybdenum sulfide and selenide with HCSs, emphasizing synthesis methods, composition tuning, heterojunction formation, as well as electrochemical applications such as water splitting and supercapacitors, while systematically discussing growth kinetics and the influence of Ni and Co based components. Finally, the article addresses the remaining challenges and outlines future prospects for TMD–HCS composite catalysts in advanced applications.