Insights into the Photoassisted Electrocatalytic Reduction of CO2 over a Two‐dimensional MoS2 Nanostructure Loaded on SnO2 Nanoparticles

Abstract

AbstractPhotoelectrochemical reduction of CO2 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 MoS2 loaded on SnO2 nanoparticles (MS/SON) was prepared for photoassisted electrocatalytic reduction of CO2 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 MoS2, 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 MoS2 increased the specific surface area from 47.64 m2 g−1 to 55.99 m2 g−1, which was helpful to expand the number of active sites. It is demonstrated that MS/SON is an excellent CO2 reduction material.