Solar-Driven Highly Active and Selective Conversion of Acetonitrile to Formic Acid over Oxygen Vacancy Engineered Tungsten Oxide

Abstract Photocatalytic activation of inert chemical bonds represents a promising route for selective conversion of organic molecules such as acetonitrile (CH3CN) into value-added products. However, as the most common reactive oxygen species, •OH radicals are nonselective and usually lead to overoxidation reactions, making it difficult to realize the target product with both high activity and selectivity in the photocatalytic system. Here, we demonstrate that, through oxygen vacancy (Vo) engineering, selective CH3CN conversion into HCOOH is enabled over a WO3 photocatalyst under mild conditions. Under simulated solar irradiation, the as-prepared Vo-rich WO3 nanosheets display notable photocatalytic CH3CN conversion performance, with a HCOOH yield rate of 8.8 mmol g–1 h–1 and a selectivity as high as 86.5%. In combination of various in situ spectroscopic techniques, it is revealed that the Vo constructs a coupling match between of •OH radicals and •CH2CN intermediates on the WO3 photocatalyst surface, which facilitates the selective conversion of CH3CN into HCOOH while preventing its overoxidation. This work extends the conversion pathway of CH3CN in a photocatalytic route and provides deeper insight into the selective conversion of inert molecules.