Self-CO₂ Recycling Photocatalytic Fuel Cell for Enhancing Degradation of Pollutants and Production of Carbon-Neutral Fuel

Photoelectrochernical oxidation is considered a promising way for the treatment of refractory organic wastewater owing to its high efficiency and low cost. However, CO2 was still the final emission product in this system. Here, we designed a novel CO2 self-driving and self-recycling photocatalytic fuel cell (PFC) system for enhancing the degradation of refractory organic pollutants and ultimately converting it into fuel. The carbon-neutral PFC system achieved an increase of 40% in organics removal and an extra C1 fuel yield rate of 6.7 mu mol g(-1) h(-1), compared to the conventional photocatalytic system. CO2 produced from wastewater degradation in the anode can be spontaneously supplied to the rotating cathode under positive pressure. The CO2 reduction reaction occurring at the cathode accelerated the electron-hole separation in photoanode facilitated the formation of C1 fuel in the cathode. The isotope tracer experiment confirmed that the carbon source of C1 products was from organics. Therefore, the light-dependent self-CO2 recycling PFC system provides new spontaneous conversion from refractory organic pollutants to green fuel.