Facile fabrication of boron-doped titanium carbide for efficient electrocatalytic nitrogen reduction

Abstract

Electrochemical nitrogen fixation is a promising strategy to achieve sustainable ammonia (NH₃) synthesis. However, the major challenge lies in simultaneously achieving high NH₃ production rates and faradaic efficiency (FE). A well-designed catalyst with high nitrogen reduction reaction (NRR) performance is urgently needed. Herein, we report a novel boron-doped titanium carbide (Ti₃C₂–B) material prepared by doping B into intercalated carbide titanium (Ti₃C₂) MXenes. The NH₃ yield of Ti₃C₂–B catalysts was examined using two detection techniques: ultraviolet-visible spectroscopy and ion chromatography. The synthesized electrocatalyst exhibited an NH₃ yield of 39.64 ± 1.4 μg h⁻¹ mg_cat.⁻¹ at −0.55 V and an FE of 11.89% ± 0.3% at −0.45 V vs. reversible hydrogen electrode (RHE), outperforming most reported NRR catalysts. Density functional theory (DFT) calculations suggest that B doping of Ti₃C₂ reduces the free energy obstacle for the rate-determining step *NNH₂ → *NNH₃, enhances the suppression of the hydrogen evolution reaction (HER), and improves NRR capabilities. B doping of 2D MXene nanosheets offers a promising avenue for developing highly efficient N₂ electrocatalysts in the future.