Comparative study of the photocatalytic activity of g-CN/MN (M = Mn, Fe, Co) for water splitting reaction: A theoretical study.

In this study, nanocomposites of g-CN/MN (where M is Mn, Fe and Co) have been designed using advanced density functional theory (DFT) calculations. A comprehensive analysis was conducted on the geometry, electronic, optical properties, work function, charge transfer interaction and adhesion energy of the g-CN/MN heterostructures and concluded that g-CN/FeN and g-CN/CoN heterojunctions exhibit higher photocatalytic performance than individual units. The better photocatalytic activity can be attributed mainly by two facts; (i) the visible light absorption of both g-CN/FeN and g-CN/CoN interfaces are higher compared to its isolated analogs and (ii) a significant enhancement of band gap energy in g-CN/FeN and g-CN/CoN heterostructures limited the electron-hole recombination significantly. The potential of the g-CN/MN heterojunctions as a photocatalyst for the water splitting reaction was assessed by examining its band alignment for water splitting reaction. Importantly, while the electronic and magnetic properties of MN systems were studied, this is the first example of inclusion of MN on graphene-based material (g-CN) for studying the photocatalytic activity. The state of the art DFT calculations emphasis that g-CN/FeN and g-CN/CoN heterojunctions are half metallic photocatalysts, which is limited till date.