Surface hydrophobic modification enhanced catalytic performance of electrochemical nitrogen reduction reaction

Electrocatalytic nitrogen reduction reaction (NRR) is a sustainable approach for NH3 production with low energy consumption. However, competing hydrogen reduction reaction (HER) in aqueous solution results in low NH3 production and Faraday efficiency (FE). Here, MoS2 nanostructures with a hydrophobic surface are synthesized by alkyl thiols modification. Aerophilic and hydrophobic surface facilitates an efficient three-phase contact of N2, H2O, and catalyst. Thus, localized concentrated N2 molecules can overcome the mass transfer limitation of N2 and depress the HER due to lowering the proton contacts. Although the active-sites decrease with the increase of the alkyl chain since the thiol may cover the active site, the optimized electrocatalyst achieves NH3 yield of 12.86 × 10−11 mol·cm−2·s−1 at −0.25 V and 22.23% FE, which are 4.3 and 24 times higher than those of MoS2-CP electrocatalyst, respectively. The increased catalytic performance is attributed to the high N2 adsorption and depressed HER.