Fe-Tio2-X/Tio2 S-Scheme Homojunction for Efficient Photocatalytic Co2 Reduction

Abstract

CO2-to-high value-added chemicals via a photocatalytic route is of interest but strangled by the low efficiency. Herein, a novel S-scheme homojunction Fe-TiO2-x/TiO2 was designed and constructed by using a facile surface modification approach whereby Fe and oxygen vacancies (OVs) introducing on the surface of the TiO2 nanorods. The as-synthesized Fe-TiO2-x/TiO2 S-scheme homojunction exhibits positive properties on promoting photocatalytic CO2 reduction: i) the nanorod structure provides numerous active sites and a radical charge transfer path; ii) the doped Fe and OVs not only synergistically enhance light utilization but also promote CO2 adsorption; iii) the Fe-TiO2-x/TiO2 S-scheme homojunction benefits photoexcited charge separation and retains high redox capacity. Thanks to those good characters, the Fe-TiO2-x/TiO2 homojunction exhibits superior photocatalytic CO2 reduction activity with optimized CO/CH4 generation rates of 122/22 μmol g-1 h-1 which exceeds that of pure TiO2 by more than 9.4/7.3 folds and most currently reported catalytic systems. This work provides a facile and universal approach to synthesize well-defined heterostructure and may inspire the construction of other more high-efficiency photocatalysts toward CO2 reduction and beyond.

Keywords: Photocatalysis, S-scheme homojunction, CO2 reduction, Surface modification, Titanium oxide