Role of interlayer and interfacial electric field generated during simultaneous HER and OER over Li intercalated g−C3N4 for efficient photocatalytic activity

Substantial variation in the photocatalytic activity on the interaction of reaction intermediates with the surface of the catalyst is governed by the charge transfer mechanism. Charge transfer within a stacked layer of photocatalyst and across the reactant-photocatalyst interface alters photocatalytic activity due to the generation of an electric field. This work addresses the synergistic effect of interlayer (Eil→) and interfacial (Eif→) electric field on the photocatalytic activity of Li-intercalated g−C3N4 (Li−CN) through the study of electronic and optical properties using density functional theory. Charge transfer analysis for simultaneous oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in the presence of two water molecules shows variation in built-in Eil→ of Li−CN as the surface reaction proceeds via the induced Eif→ generated by the reactants on Li−CN. This change in Eil→ alters the energy barrier of the next reaction step through directional charge transfer. The present study reveals the mutual interplay of Eil→, Eif→ and adsorption energy of reaction adsorbates for improved photocatalytic activity of Li−CN for efficient OER and HER.