Two-dimensional g-C3N4/Ca2Nb2TaO10 nanosheet composites for efficient visible light photocatalytic hydrogen evolution

•Novel g-C3N4/Ca2Nb2TaO10 nanosheet composite was simply prepared by exfoliation-reassembly method.•The hybridization between the g-C3N4 and Ca2Nb2TaO10 nanosheets provides an intimate interfacial connection.•The synergistic effect of g-C3N4 and Ca2Nb2TaO10 nanosheets is exemplified for improving photocatalytic H2 evolution under visible light irradiation.

Scalable g-C3N4 nanosheet powder catalyst was prepared by pyrolysis of dicyandiamide and ammonium chloride followed by ultra-sonication and freeze-drying. Nanosheet composite that combines the g-C3N4 nanosheets and Ca2Nb2TaO10 nanosheets with various ratios were developed and applied as photocatalysts for solar hydrogen generation. Systematic studies reveal that the g-C3N4/Ca2Nb2TaO10 nanosheet composite with a mass ratio of 80:20 shows the best performance in photocatalytic H2 evolution under visible light-irradiation, which is more than 2.8 times out-performing bare g-C3N4 bulk. The resulting nanosheets possess a high surface area of 96 m2/g, which provides abundance active sites for the photocatalytic activity. More importantly, the g-C3N4/Ca2Nb2TaO10 nanosheet composite shows efficient charge transfer kinetics at its interface, as evident by the photoluminescence measurement. The intimate interfacial connections and the synergistic effect between g-C3N4 nanosheets and Ca2Nb2TaO10 nanosheets with cascading electrons are efficient in suppressing charge recombination and improving photocatalytic H2 evolution performance.

Graphical abstractA new type of visible light active composite containing exfoliated g-C3N4 nanosheets and Ca2Nb2TaO10 nanosheets was prepared. Systematic studies reveal that the g-C3N4/Ca2Nb2TaO10 nanosheet composite with a mass ratio of 80:20 exhibits the best performance in photocatalytic H2 evolution under visible light-irradiation, which is more than 2.8 times out-performing bare g-C3N4 bulk. The enhancement of photocatalytic H2 evolution of the g-C3N4/Ca2Nb2TaO10 composite is attributed to the intimate interfacial connection and synergistic effect between g-C3N4 nanosheets and Ca2Nb2TaO10 nanosheets with cascading electrons for efficient charge recombination suppression.Download high-res image (152KB)Download full-size image