In-Ti-Cu Trimetallic Sites Mediated Co2 Coordination Model and Enhanced Surface Frustrated Lewis Pairs for Controlling the Selectivity of Photoreduction of Co2

Abstract

The hollow tubular CuIn5S8 was prepared by MOF derivation method. The designed Ti site was introduced into the CuIn5S8 lattice by the same lattice replacement strategy. Because In3-δ-Ti4-Cu2 at the active interface of TCIS-2 can generate Cu1-δ and Ti4+δ sites, and the Ti4+δ-S2- surface frustrated Lewis pairs were successfully constructed. The CO selectivity of CuIn5S8 is 81.67% (7.35μmol.g-1.h-1), but the CH3OH selectivity of TCIS-2 reaches 96.89% (42.67μmol.g-1.h-1). The excellent activity of TCIS-2 is mainly attributed to the formation of Ti4+δ-S2- enhanced SFLPS, and the construction of CO2 coordination model mediated by In3-δ-Ti4+δ-Cu2-δ trimetal sites. The photocatalytic CO2 reduction results and DFT calculation results show that the coordination model of In3-δ-Ti4+δ-Cu2-δ and Ti4+δ-S2- SFLPS realized the regulation of the product from CO to CH3OH. In addition, by placing the catalyst on the gas-liquid contact surface for the reaction, it is beneficial to the separation of the gas and liquid products, and to improve the yield and selectivity of methanol. This work not only provides an effective strategy for the construction of coordination models mediated by trimetal sites and enhanced SFLPS, but also provides a new idea for tailoring the selectivity of the CO2 photoreduction.

Keywords: trimetallic sites, coordination model, CO2 photoreduction, surface frustrated Lewis pairs, CuTixIn5-xS8