Cu-doped TiO2 nanofibers coated with 1T MoSe2 nanosheets providing a conductive pathway for the electron separation in CO2 photoreduction

Abstract

Efficient solar-driven conversion of CO2 into valuable chemical energy offers a promising way to address the issues of energy shortage and climate change. However, the weak and slow charge kinetics severely impede CO2 photoreduction. Herein, hybrid-phase MoSe2 (1 T-2H MoSe2) nanosheet-coated Cu-doped TiO2 nanofibers (CuTiO2 NFs) were prepared using a solvothermal method. Different characterizations confirmed the successful doping of Cu into a TiO2 crystal lattice and the generation of stable 1 T-2H MoSe2 in the composite samples. The developed internal electric field drives electrons from the Cu-TiO2 NFs to MoSe2, demonstrating the presence of a Step-scheme (S-scheme) charge transfer path in the Cu-TiO2 NFs/1T-2H MoSe2 heterostructure, which allows efficient and selective CO2 photoreduction. In addition, the optimum sample contains an abundant 1 T MoSe2 coupled with Cu+/Cu0 which offers copious active sites to improve CO2 adsorption and subsequent conversion to CO and CH4. The optimum sample exhibits a remarkable CO2 selectivity of 90%. These findings provide new possibilities for improving the preparation of efficient photocatalysts for the photoreduction of CO2.