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

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 (kapp ≈ 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.