Green and Facile Fabrication of Metal Oxide/Red Phosphorus Composite Catalysts for CO2 Photoreduction

Photocatalyzed CO2 reduction (CO2RR) transfers CO2 into valuable products using renewable energy, attracting widespread attention. Composite catalysts fabricated with TiO2 and red phosphorus (RP) might exhibit competitive advantages, but effective interphase binding is difficult to forge. The composites therefore require complex and energy-consuming syntheses, severely hindering their application in CO2RR. In this work, TiO2/RP composites with hyperefficient interphase contact, which outperform various elaborately designed catalysts, are directly prepared from commercially available materials via a green and facile hydrothermal approach. The low heating temperature and sole solvent of water diminish the energy input for synthesis and imply a potential opportunity to propel CO2RR with industrial waste heat and cooling water. Experimental and computational analyses reveal that hydrothermal synthesis reduces the interfering oxidized species on the exterior surface of RP, facilitating the relatively less favored interphase contact between TiO2 and nonoxidized RP. Photoelectron transfer and catalytic performance of the composites are hence drastically enhanced. Further improvement of activity is feasible by slightly elevating the heating temperature, time, or solution acidity. Attributing to the universal applicability of this green approach, different metal oxide/RP composites (e.g., WO3/RP) are similarly prepared, consistently boosting the reaction rate multiple times.