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.