Promoting photocatalytic CO reduction to CH via a combined strategy of defects and tunable hydroxyl radicals.

A well-designed photocatalyst with excellent activity and selectivity is crucial for photocatalytic CO conversion and utilization. TiO is one of the most promising photocatalysts. However, its excessive surface oxidation potential and insufficient surface active sites inhibit its activity and photocatalytic CO reduction selectivity. In this work, highly dispersed BiTiO was introduced into defective TiO to adjust its oxidation potential and the generation of radicals, further inhibiting reverse reactions during the photocatalytic conversion of CO. Moreover, an in situ topochemical reaction etching route was designed, which achieved defective surfaces, a contacted heterophase interface, and an efficient electron transfer path. The optimized heterophase photocatalyst exhibited 93.9% CH selectivity at a photocatalytic rate of 6.8 μmol·g·h, which was 7.9 times higher than that of P25. This work proposes a feasible approach to fabricating photocatalysts with well-designed band structures, highly dispersed heterophase interfaces, and sufficient surface active sites to effectively modulate the selectivity and activity of CO photoreduction by manipulating the reaction pathways.