Face-to-Face Interfacial Assembly of Ultrathin g-C₃N₄ and Anatase TiO₂ Nanosheets for Enhanced Solar Photocatalytic Activity

Abstract

Face-to-face interfacial assembly of TiO₂-g-C₃N₄ hybrid (2D TCN-A) is developed by surfactant-assisted hydrothermal treatment forming a sandwich structure of anatase TiO₂ nanosheets (TiO₂-A, 5-6 monolayers) and g-C₃N₄ nanosheets (∼3 monolayers). Post air-annealing is found effective for insertion of oxygen to the hybrid, which remedies the oxygen vacancies of TiO₂ (B) nanosheets and converts it to anatase nanosheets. The enhanced light adsorption, increased donor density, and prolonged life of charge carries are achieved by variation of bandgap and the formation of heterojuction between the two kinds of nanosheets, facilitating separation and transfer of charge carriers. The 2D TCN-A-70 nanosheets show a high photodegradation rate of methyl orange (k_app ≈ 0.189 min^-1) and photocatalytic evolution rate of hydrogen (18200 μmol g^-1 h^-1). This 2D nanosheets hybrid is potentially useful in alleviating environmental and energy issues.