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

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/Nb2CTx 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 Nb2CTx 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.