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

Conductive TiO x clusters with Ti 3+ species and Ti–O 5 unsaturated coordination structure were incorporated into nanosheets-assembled hollow ZnIn 2 S 4 by NH 2 -MIL-125(Ti) as template for solar CO 2 reduction. This typical photocatalysts exhibit highly selective photoreduction of CO 2 , achieving a super high visible-light photocatalytic CO evolution activity. • Conductive Ti 3+ -rich TiO x clusters incorporated into hollow semiconductors were synthesized. • The catalyst exhibits high activity and selectivity toward CO 2 photoreduction. • The active sites were identified, inducing efficient trapping of electrons. • This performance is ascribed to efficient charge separation. Solar-driven CO 2 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 CO 2 photoreduction performance. Herein, conductive Ti 3+ -rich TiO x clusters with unsaturated Ti–O 5 coordination incorporated into nanosheets-assembled hollow sulfide semiconductors were prepared through a versatile transformation strategy by using NH 2 -MIL-125(Ti) metal–organic–framework as precursor. This typical photocatalysts exhibit highly selective photoreduction of CO 2 , achieving a super high visible-light photocatalytic CO evolution activity of 1100 μmol g −1 h −1 . The active sites were identified on the surface of conductive TiO x clusters, inducing efficient trapping of photogenerated electrons at the interface and suppressing H 2 generation. This enhanced performance is ascribed to Ti 3+ -rich TiO x 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 CO 2 .