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

摘要

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.