Synergistic collaboration of g-C3N4/SnO2 composites for enhanced visible-light photocatalytic activity

A series of novel composites g -C 3 N 4 /SnO 2 were first synthesized using a facile two-step process. Through systematic sample characterization, it is demonstrated that all composites consist of two components: g -C 3 N 4 with a low specific surface area and SnO 2 nanoparticles with a large specific surface area. Within the composites, component of SnO 2 nanoparticles dispersed well onto the component g -C 3 N 4 with a clear interface between each other. The interactions between both components are strong, as confirmed by variations in binding energies and lattice parameters. A synergistic collaboration is achieved for the composites, as contributed by surface adsorption of organics from π–π conjugation of component g -C 3 N 4 , improved separation efficiency of photo-generated carriers from interfacial interactions between both components, and increased surface area from component SnO 2 nanoparticles. As a consequence, these composites exhibit a significantly enhanced photocatalytic activity towards MO degradation under visible light irradiation. The optimum photocatalytic performance is achieved at 47.5   wt% SnO 2 , showing a reaction kinetic constant of 0.0078, which is much higher than those of components g -C 3 N 4 and SnO 2 . With the unique synergistic collaboration, the optimized composite with Pt additives is also successfully applied to high-efficiency production of hydrogen from water splitting under visible light irradiation.