Engineering unsaturated coordination of conductive TiOx clusters derived from Metal–Organic–Framework incorporated into hollow semiconductor for highly selective CO2 photoreduction

Abstract

Solar-driven CO2 conversion into fuels is a promising solution toward green energy conversion. It is a challenge to regulate the precise structure of photocatalysts at the atomic scale, facilitating the charge transfer and improving CO2 photoreduction performance. Herein, conductive Ti3+-rich TiOx clusters with unsaturated Ti–O5 coordination incorporated into nanosheets-assembled hollow sulfide semiconductors were prepared through a versatile transformation strategy by using NH2-MIL-125(Ti) metal–organic–framework as precursor. This typical photocatalysts exhibit highly selective photoreduction of CO2, achieving a super high visible-light photocatalytic CO evolution activity of 1100 μmol g−1h−1. The active sites were identified on the surface of conductive TiOx clusters, inducing efficient trapping of photogenerated electrons at the interface and suppressing H2 generation. This enhanced performance is ascribed to Ti3+-rich TiOx clusters as an efficient cocatalyst on sulfide semiconductor providing more active sites due to electrical conductivity and unsaturated coordination environment. This work provides a promising approach to enhance photocatalytic performance of the catalysts coupled by unique metal oxide clusters for selective photoreduction of CO2.