Hydrophobic and Electronic Properties of the E‐MoS2 Nanosheets Induced by FAS for the CO2 Electroreduction to Syngas with a Wide Range of CO/H2 Ratios

Abstract

AbstractThe electrochemical CO2 reduction reaction (CO2RR) to produce CO and H2 (syngas) is a promising method for clean energy, but challenges remain, such as controlling the CO/H2 ratios required for the syngas yield. Herein, hydrophobic exfoliated MoS2 (H‐E‐MoS2) nanosheets are fabricated from bulk MoS2 by a cost‐effective ball‐milling method, followed by decoration with fluorosilane (FAS). H‐E‐MoS2 is a cost‐effective electrocatalyst capable of directly reducing CO2 and H2O for tuneable syngas production with a wide range of CO/H2 ratios (from 1:2 to 4:1). In addition, H‐E‐MoS2 shows a high current density, 61 mA cm−2 at −1.1 V, and the highest CO FE of 81.2% at −0.9 V, which are higher than those of unmodified MoS2. According to density functional theory calculations, FAS decoration on the surface of MoS2 electrode can change the electronic properties of the edge Mo atom, which facilitates the rate‐limiting CO‐desorption step, thus promoting CO2RR. Moreover, the hydrophobic surface of H‐E‐MoS2 depressed the H2 evolution reaction and created abundant three‐phase contact points that provided sufficient CO2. The hydrophobization of the electrode may provide an effective strategy for easily tuning the CO/H2 ratio of syngas in a large range for the direct electroreduction CO2 to syngas with an optimized CO/H2 ratio.