Cu+–Ti3+ interface interaction mediated CO2 coordination model for controlling the selectivity of photocatalytic reduction CO2

Cu2O clusters/TiO2 nanosheet (CNSX) as a photocatalyst is created to tailor the selectivity of CO2 photoreduction. The catalysts show different selectivity of CO and CH4 with the increase of Cu2O mass. TiO2 nanosheet (NS) exhibits 100% selectivity of CH4 with a rate of 37.6 μmol g−1 h−1. However, CO2 would be converted to CO with selectivity of 98% and yield of 162.6 μmol g−1 h−1 on 5 wt% Cu2O/TiO2 nanosheet (CNS3). The Ti···CO2–···Ti coordination intermediate on Ti3+ sites is responsible for CH4 formation, whereas the Cu···CO2···Ti specie on Cu1-δ and Ti4+δ sites determines CO production. The Cu+–Ti3+ interface interaction on CNSX surface can generate Cu1-δ and Ti4+δ sites and eliminate Ti3+ via the charge transfer from Ti3+ to Cu+. The selectivity is thus tailored effectively by Cu+–Ti3+ interface interaction mediated CO2 coordination model. This work would offer a new perspective for tailoring the selectivity of CO2 photoreduction.