2D-2D MnO2/g-C3N4 heterojunction photocatalyst: In-situ synthesis and enhanced CO2 reduction activity

A novel MnO2/g-C3N4 heterojunction composite was synthesized via a simple in-situ redox reaction between KMnO4 and MnSO4 center dot H2O adsorbed on the surface of g-C3N4 for the first time. MnO2 featuring 2D delta-phase layered structure was intimately attached onto the surface of g-C3N4 layers via -C-O- bonding. Notably, the synthesized MnO2/g-C3N4 photocatalyst showed substantially enhanced photocatalytic activity in the reduction of CO2 than pure g-C3N4 and MnO2. The highest CO production amount of 9.6 mu mol g(-1) has been obtained at an optimized loading amount of MnO2 under 1 h irradiation of a 300 W Xe lamp. The incorporation of narrow band gap MnO2 on the surface of g-C3N4 enhanced its light harvesting ability. And the solid hetero-interface between MnO2 and g-C3N4 together with their well matched band structure was favorable for the separation of photo-induced carriers, consequently enhanced its photocatalytic activity. This novel 2D-2D MnO2/g-C3N4 heterostructure is expected to have great potentials in CO2 photoreduction. (C) 2017 Elsevier Ltd. All rights reserved.