Progress in graphdiyne and phosphorene based composites and heterostructures as new age materials for photocatalytic hydrogen evolution

Hydrogen evolution from water splitting using semiconductor photocatalysis is regarded as a sustainable and clean energy solution. Among various new age materials, the two-dimensional (2D) monoelemental materials as graphdiyne (GDY) and phosphorene (PN) showing excellent performance owing to their 2D atomic structure and unique properties, have drawn considerable attention. Graphdiyne (GDY) is a two-dimensional carbon-based compound having sp and sp² hybridized carbon, diacetylene linkage, triangular holes framework and customizable band gap. Different stacking arrangements and homogenous pores in GDY can produce electronic characteristics, opening the door to intriguing energy applications. On the other hand, phosphorene derived from black phosphorous (BP) exhibits strong hole mobility, a variable band gap and broad optical absorption spectrum. With a significant increase in photo-excited charge-separation efficacy, the development of heterostructured photocatalysts driven by BP/PN and GDY has recently become the subject of study in photocatalysis. The recent advancements in development of phosphorene and graphdiyne and their accompanying heterostructured photocatalysts is outlined here, along with their structure, characteristics, synthetic routes and photocatalytic applications. In addition, the photocatalytic applications of PN and GDY based composites and heterostructures have been reviewed and summarised for photocatalytic hydrogen evolution through water splitting. Environmental stability of these heterostructured photocatalysts and the difficulties they pose have been thoroughly investigated for their more effective and extensive uses in the future.