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

Photoelectrochemical oxidation is considered a promising way for the treatment of refractory organic wastewater owing to its high efficiency and low cost. However, CO 2 was still the final emission product in this system. Here, we designed a novel CO 2 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 μmol g –1 h –1, compared to the conventional photocatalytic system. CO 2 produced from wastewater degradation in the anode can be spontaneously supplied to the rotating cathode under positive pressure. The CO 2 reduction reaction occurring at the cathode accelerated the electron–hole separation in photoanode and facilitated the formation of C1 fuel in the cathode. The isotope tracer experiment confirmed that the carbon source of C1 fuel products was from organics. Therefore, the light-dependent self-CO 2 recycling PFC system provides new insight into the spontaneous conversion from refractory organic pollutants to green fuel.