Constructing an electron-rich interface over an Sb/Nb2CTx–MXene heterojunction for enhanced electrocatalytic nitrogen reduction

Abstract

Electrocatalytic dinitrogen fixation holds great promise as a sustainable technology for future NH₃ synthesis, and developing electrocatalysts for the nitrogen reduction reaction (NRR) with high activity and selectivity is highly desirable yet challenging. Herein, we reported that interface electronically coupled Sb/Nb₂CT_x could be a highly efficient NRR catalyst which delivered an NH₃ yield of 49.8 μg h⁻¹ mg⁻¹ with faradaic efficiencies as high as 27.3%, representing the highest NRR selectivity achieved in MXene-based catalysts. Density functional theory calculations revealed that the coupling of Sb and Nb₂CT_x could generate an electron-rich interface enabling the downshift of the p-band center of interfacial Sb atoms, which served as main active sites to promote the N₂ activation and hydrogenation while restricting the competing hydrogen evolution.