Layered 2D Transition Metal Dichalcogenides (MX 2 ; M=Mo, W; X=S, Se, Te) Nanosheets and Their Composites for Photocatalytic Applications: A Review

Abstract

Current, in-depth research on layered two-dimensional transition metal dichalcogenides (2D-TMDCs) has been triggered by a progression of investigative theoretical predictions and experimental observations of unanticipated electronic, optical and photochemical properties in nanosheets and their composites of this family of materials, especially their most archetypal member, MoS2. MoS2 nanosheets show a fantastic array of properties to be a potential candidate as an active photochemical agent, thus contributing to the gateway of an immense number of problems. However, from the past 2-3 years, the other family members, MoX2 (X=Se, Te) and WX2 (X=S, Se, and Te), are stepping out of the shadows of the famous molybdenum disulfide and establishing their own identity. This review aims to arrange and combine information on photocatalytic hydrogen production, water splitting, dye degradation, visible light photocatalytic activity, photocatalytic CO2 reduction, and environmental remediation of layered 2D-TMDCs nanosheets and their composites. Due to the popularity of MoS2, the central focus of the review is on MoSe2, MoTe2, WS2, WSe2. This work presents a systematic report on the applications of various 2D metal dichalcogenides as a whole, exploring their prime role in enhancing individual performance like the evolution of hydrogen gas, reduction of CO2, and degradation of toxic dyes or pollutants. All such treatments are of utmost significance for having a better environment to live. Thus, this specifies the importance of 2D-TMDCs towards the attainment of a sustainable homeland. In recent years WTe2 has emerged as a potential candidate for giant magnetoresistance and superconductivity. However, in the case of photocatalytic applications, it is not very economical for commercial development. Therefore, WTe2 is excluded from our discussion.