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

A series of novel composites g-C3N4/SnO2 were first synthesized using a facile two-step process. Through systematic sample characterization, it is demonstrated that all composites consist of two components: g-C3N4 with a low specific surface area and SnO2 nanoparticles with a large specific surface area. Within the composites, component of SnO2 nanoparticles dispersed well onto the component g-C3N4 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 pi-pi conjugation of component g-C3N4, improved separation efficiency of photo-generated carriers from interfacial interactions between both components, and increased surface area from component SnO2 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% SnO2, showing a reaction kinetic constant of 0.0078, which is much higher than those of components g-C3N4 and SnO2. 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. (C) 2014 Elsevier B.V. All rights reserved.