Insights into the Photoassisted Electrocatalytic Reduction of CO 2 over a Two‐dimensional MoS 2 Nanostructure Loaded on SnO 2 Nanoparticles

Photoelectrochemical reduction of CO 2 to value‐added chemicals and fuels is an attractive strategy to store renewable energy and mitigate greenhouse gas emissions. In this study, based on the density functional theory (DFT) calculation, a two‐dimensional nanostructure MoS 2 loaded on SnO 2 nanoparticles (MS/SON) was prepared for photoassisted electrocatalytic reduction of CO 2 to HCOOH through a two‐step process of facile hydrothermal and pyrolysis method. Through physical structure characterization and photoelectric performance test, the results indicated that the 5 % MS/SON exhibits exclusive HCOOH selectivity, the maximum FE is 43.8 %, the current density reached to 9 mA cm −2 at −1.4 V and the photocurrent value is 12.5 μA cm −2 under 0.5 V bias. The overpotential is as low as 245 mV. Besides, after the introduction of MoS 2 , there is a red shift in the adsorption band edge from 380 nm to 500 nm, indicating an enhancement of light response; the peak intensity of photoluminescence (PL) decreased, showing that the electron and hole are effectively separated; the values of electrochemical impedance spectroscopy (EIS) and Tafel plots (70 mV dec −1 ) were smaller than other ratios, demonstrating that the faster charge transfer rate; the proper introduction of MoS 2 increased the specific surface area from 47.64 m 2  g −1 to 55.99 m 2  g −1 , which was helpful to expand the number of active sites. It is demonstrated that MS/SON is an excellent CO 2 reduction material.