Advanced strategies for modifying the water splitting performance of MoSe2 photocatalyst: A critical review of recent progress

Water splitting technology is rapidly evolving in order to generate H2 in a sustainable manner to amend the global energy crisis. Water splitting over semiconductor catalyst nanoparticles for large-scale hydrogen production has shown to be a simple and affordable procedure, attracting researchers from around the world for more fruitful studies and development in the field of photocatalysis. In this respect, MoSe2 is a promising semiconductor photocatalyst owing to its non-toxic nature, low Gibbs free energy, high metallic character, impressive opto-electronic properties, and outstanding photocatalytic performance. Moreover, the 2D nature of MoSe2 allows the easy tuning of the bandgap to suit H2 evolution reaction application by simple synthesis techniques. Therefore, in this review, we have comprehensively discussed the influence of morphology on photocatalytic water splitting with a main focus on the nanostructure modifications to modulate the properties of MoSe2. In detail, starting from the crystal structure and optimal photocatalytic features of MoSe2, insights into photocatalytic water splitting have been highlighted. Various modes of nanostructure designs involving hydro(solvo)thermal, CVD, PVD, exfoliation, and intercalation are outlined. The lower bandgap energy is subjected to a high rate of photoinduced excitons recombination, which reduces its photocatalytic efficiency. Therefore, modification techniques such as doping, heterostructure construction, and vacancy generation are presented in order to concurrently improve the photocatalytic water splitting performance. Finally, the study concludes with a summary of recent advancements and anticipated potential trends in this area to instigate further research endeavours.