In situ construction of layered K3Ti5NbO14/g-C3N4 composite for improving visible-light-driven photocatalytic performance

A simple calcination approach was performed to synthesize layered K3Ti5NbO14/g-C3N4 (TNCN) composites, in which g-C3N4 was formed both within the interlayers and on the surface of N-K3Ti5NbO14. The photocatalytic activity of samples was evaluated by the visible-light photocatalytic degradation of rhodamine B (RhB). It was found that TNCN composite with a proper mass ratio of N-K3Ti5NbO14 to g-C3N4 exhibited the rapid rate of charge separation and high efficiency of light harvesting due to the synergetic effects of layered heterojunction and N doping, leading to an excellent photocatalytic activity. Especially, the in situ intercalated mono-layered g-C3N4 nanosheets can significantly increase the contact area between K3Ti5NbO14 layers and g-C3N4 nanosheets for efficient charge transfer across the interface, showing the greater effect on the enhanced photocatalytic activity. The active species trapping experiments and ESR measurements were carried out to evaluate the contribution of the active species in this photocatalytic degradation process. It was revealed that both superoxide radicals (O-center dot(2) (-)) and holes (h(+)) are the main active species, while hydroxyl radicals ((OH)-O-center dot) made a minor contribution to the photocatalytic degradation of RhB.