2D transition metal Dichalcogenides: Synthesis methods and their pivotal role in Photo, Piezo, and photo-piezocatalytic processes

Over the past two decades, the field of two-dimensional (2D) layered materials has witnessed a remarkable advancement, owing to the discovery of the exceptional properties of graphene. This sustained growth is a testament to the significance of this breakthrough and its ongoing impact on research and development in this field. Graphene has already found its way into various industries, but the next material from the 2D family that is expected to make a mark is transition metal dichalcogenide. These materials possess various wondrous properties, such as atomic-level thickness, flexible nature, tunable band gap, and excellent thermal, mechanical, and chemical stability. Water cleaning is one of the major challenges faced by the world today, and photocatalysis has emerged as a promising solution. However, its present efficiency is not yet enough to meet industrial requirements. The piezoelectric effect, which utilizes mechanical deformations to generate a similar effect as photocatalysis, has lately added attention as a method to increase efficiency. Specifically, 2D-transition metal dichalcogenides (TMDCs) in odd layers possess a great piezoelectric effect, making them ideal for piezo-catalysis. The addition of the piezoelectric effect to photocatalysis can increase efficiency, and 2D semiconductors have the potential to possess both effects simultaneously, leading to a new area called the piezo-phototronic effect. This review focuses on the fundamental concepts and recent advancements in the field of 2D-TMDCs, specifically concerning piezocatalysis, photocatalysis, and combined photo-piezocatalysis processes. Finally, this review discusses the critical challenges and future perspectives.