Insights into the effect of Ni doping on In2S3 for enhanced activity and selectivity of photocatalytic CO2 reduction

The limited photocatalytic CO 2 reduction performance mainly lies in the low utilization of photogenerated electrons during the reaction. In this work, we developed the defect level within the Ni-doped In 2 S 3 nanotube photocatalysts via a simple solvothermal method to increase the available amount of photogenerated electrons for enhanced photocatalytic CO 2 reduction performance than the pristine In 2 S 3 . The introduction of Ni element into the lattice of In 2 S 3 could significantly improve the photocatalytic activity and selectivity without destruction of the nanotube structure of In 2 S 3 . The yield of CO reaches 243.2 μmol/g/h under visible light , which is the highest reported value among In 2 S 3 photocatalysts, and is 8.2 times more than the pure In 2 S 3 . Moreover, by modulating the doping amount of Ni element, the selectivity of CO varied from 27.7% to 51.0%. Further characterizations suggest that the doping of Ni element altered the electronic bandgap arrangement of In 2 S 3 , where the position of the conduction band is conducive to the activation of CO 2 molecules. Moreover, the defect level resulting from Ni-doping not only facilitates the separation of photoexcited electron-hole pairs but also suppresses the recombination of electrons and holes. This study provides an available and reliable strategy for enhancing the photocatalytic CO 2 reduction performance of related sulfide photocatalytic materials in future studies. • The yield of 243.2 μmol/g/h for CO is 8.2 times that of the pure In 2 S 3 . • CO evolution rate in this work is the highest. • The selectivity of CO varied from 27.7% to 51.0% with a huge improvement. • The doped Ni increased the utilization of photogenerated electrons.