Potential for H2 Generation Using 2D-g-C3N4 Nano-Photocatalysts

The discovery of graphene nanosheets (NSs) opened a flood gate of activities for studying graphene and graphene like hexagonal lattices. Particularly, the photoelectronic properties of these 2D-layered materials are of significance as they can be modified by changing their atomic arrangements. The zero-band gap of graphene did not in principle favour for switching applications against silicon. In contrast, graphitic carbon nitride (GCN), closely resembling graphene, exhibits semiconducting behaviour with excellent photoelectronic properties. GCN could photocatalytically produce H2 by water splitting in the presence of solar radiation. Extensive theoretical and experimental studies are currently going on to convert it not only into quantum dots (QDs) and nanotubes (NTs), but also to conjugate with other 2D-NSs. The introduction of lattice defects during doping and heterojunction formation in combination with other 2D nanomaterials turned out useful in influencing photogenerated charge carrier recombination and subsequent transport properties enabling them to participate in redox reaction at the surface. This entire process of photocatalytic effect in ideal monolayer of GCN-NS involving intermediate steps like photogeneration of electrons and holes, exciton formation, charge carrier separation, and subsequent participation in redox reaction, to generate hydrogen from splitting water, has theoretically been simulated using DFT models to understand the details at different timescales and spatial resolutions. The experimental side of developing GCN-NSs based photocatalysts has not been without challenges. This chapter describes about the salient progress made in preparing GCN-NS-based photocatalyst for H2 generation available from the current publications. It is still too early to say that these photocatalysts would be crossing the viability barrier of 10% for their large-scale applications in meeting the global green energy alternative in place of fossil fuels and reaching the zero pollution. Learning objectives: