Highly Selective Formation of CO from Domestic Wastewater with Zero CO2 Emissions through Solar Energy Catalysis

Utilizing two of the Earth's most abundant and inexhaustible resources, sunlight and domestic wastewater, to produce value-added CO presents an immense opportunity. Here, we present a novel strategy to selectively generate CO from domestic wastewater with the aid of concentrated solar power and high-entropy sulfide photocatalysts. Our designed system achieves an impressive CO yield of 35 μmol g-1 h-1 with 100% selectivity, showcasing the feasibility of utilizing solar energy alone to drive the heat-promoted photoreaction. Mechanistic investigations divulged the generation of a non-radical 1O2 species with a moderate redox potential. This process enables mild oxidation of carbonaceous organic matter in domestic wastewater, rather than complete mineralization of carbonaceous organic matter and reducing greenhouse gas emissions such as CO2 and CH4 during organic matter degradation. The findings present an effective and promising approach for low-carbon wastewater treatment, highlighting the potential of CO production from wastewater through solar energy catalysis. Through the rational design of the outdoor photocatalytic equipment, close to 100% selectivity from real domestic wastewater to CO gas was successfully achieved.