Improved visible light responsive photocatalytic hydrogen production over g-C3N4 with rich carbon vacancies

Graphitic carbon nitride (g-C3N4) has aroused wide concern in the domain of photocatalytic hydrogen production owing to its excellent advantages. However, the high recombination rate of photoinduced electron-hole pairs and finite surface area limit the photocatalytic performance of g-C3N4. In this demonstration, g-C3N4 photocatalytic material (VCN) with rich pore structures and carbon vacancies was obtained by heat-treating of g-C3N4 in NH3 atmosphere. The pore structures endow VCN with a higher specific surface area and new active surfaces. Meanwhile, introduction of carbon vacancies increases the electrical conductivity of VCN and the mobility of photoinduced carriers, which markedly enhances the separation efficiency of photoexcited carriers. Furthermore, VCN also shows a wider light response range and stronger visible light absorption capacity. Therefore, VCN has a better photocatalytic hydrogen evolution performance with visible light than the pristine g-C3N4, and photocatalytic hydrogen evolution performance of VCN is approximately 4.4 times that of the pristine g-C3N4.