In situ growth of WO3−x nanowires on g-C3N4 nanosheets: 1D/2D heterostructures with enhanced photocatalytic activity
We have constructed a new type of 1D/2D heterostructure by growing WO3−x nanowires on the surface of g-C3N4 nanosheets through a simple solvothermal method. The created WO3−x/g-C3N4 heterojunction allows for effective electron transfer from excited g-C3N4 nanosheets to WO3−x nanowires, which leads to enhanced photocatalytic activities for methyl orange (MO) degradation. Further studies by using different active species as capture agents reveal that superoxide radicals are mainly responsible for MO degradation. The enhanced photocatalytic activity over the WO3−x/g-C3N4 heterojunction is attributed to the abundant oxygen vacancies on the WO3−x nanowire surface, which results in a considerable amount of free electrons on WO3−x nanowires with promoted conductivity. As such, the injected photo-electrons from g-C3N4 can freely transport along the WO3−x nanowires to promote charge separation on g-C3N4. Further, the large nanowire surface with strong capability for O2 adsorption would provide the injected electrons with a high chance to reduce the surface adsorbed oxygen molecules and generate superoxide radicals for MO degradation.