Enhancing Electrocatalytic Nitrogen Reduction on Few-Layer Antimonene in an Aqueous Potassium Sulfate Electrolyte
Guilan Fan, Wence Xu, Jinhan Li, Youxuan Ni, Meng Yu, Fangming Liu, Fangyi Cheng
Abstract
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.