Visible-light responsive photocatalytic fuel cell with gas-diffusion g-C3N4/TiO2 heterojunction photoanode for simultaneously degrading VOCs and generating electricity

The use of a gas diffusion photoanode for a photocatalytic fuel cell is promising to simultaneously degrade VOCs and generate electricity. However, conventional gas-diffusion photoanode faces the issues of inefficient solar energy utilization and serious electron-hole recombination. Herein, a visible-light-responsive gas-diffusion g-C 3 N 4 /TiO 2 heterojunction photoanode is developed for simultaneous degradation of toluene and generation of electricity. In addition to the intrinsic feature of reduced mass transfer resistance of VOCs to the photocatalytic surface, such a gas-diffusion photoanode not only extends the photo-response spectrum, but also enhances charge separation. Accordingly, the photocatalytic fuel cell with the newly-developed photoanode demonstrates superior discharging performance and toluene removal efficiency over the gas-diffusion TiO 2 and g-C 3 N 4 photoanodes. The maximum power density achieved by the gas-diffusion g-C 3 N 4 /TiO 2 heterojunction photoanode is 0.0375 mW/cm², while the maximum toluene removal efficiency reaches 43.8 %. This study has promoted the development of photocatalytic fuel cells for the degradation of VOCs and electricity generation.