Enhancing Electrocatalytic Nitrogen Reduction on Few-Layer Antimonene in an Aqueous Potassium Sulfate Electrolyte

The electrochemical nitrogen reduction reaction (NRR) is an eco-friendly route for ambient N₂ fixation with renewable energy but still suffers from low selectivity and sluggish kinetics owing to formidable N₂ activation and the competitive hydrogen evolution reaction (HER). Herein, efficient electrocatalytic NRR is reported on few-layer antimonene in an aqueous K₂SO₄ electrolyte. Density functional theory (DFT) calculations reveal enhancement of NRR kinetics on antimonene with active edges and surface-adsorbed hydrated potassium cations. Combined DFT and comparative ab initio molecular dynamics simulations on antimonene in alkali cation-containing electrolytes indicate that K⁺ increases the proton migration energy barrier in an interfacial water layer, thus suppressing the HER and improving the NRR selectivity. Experimentally, the prepared few-layer antimonene exhibits a high NH₃ yield rate of 44.6 μg h^–1 mg^–1 with a Faradaic efficiency of 29.6% in 0.5 M K₂SO₄. This work suggests the promising use of a group-VA elementary two-dimensional (2D) layered material for nitrogen fixation and provides a new insight into the role of alkali cations in modulating NRR electrocatalysis.