Doped-nitrogen enhanced the performance of Nb₂CT_x on the electrocatalytic synthesis of H₂O₂

Electrochemical oxygen reduction reaction (ORR) for preparing hydrogen peroxide (H₂O₂) is a promising way to replace the anthraquinone method. The key to H₂O₂ production is the development of catalysts to regulate the oxygen reduction reaction pathway. Here, nitrogen-doped Nb₂CT_x was prepared by NH₃ annealing method. Compared with precursor Nb₂AlC (67.01%) and pure Nb₂CT_x (75.70%), nitrogen-doped Nb₂CT_x exhibited excellent performance for 2e⁻ ORR with > 90% H₂O₂ selectivity (at 0.4 V vs. reversible hydrogen electrode (RHE)). Faradic efficiency of nitrogen-doped Nb₂CT_x reached 80.75%, whereas those for Nb₂AlC and Nb₂CT_x were 60.35% and 39.27%, respectively. A desirable catalytic stability for 50 h was observed. Density functional theory (DFT) calculations indicated excellent activity of the nitrogen-doped Nb₂CT_x was attributed to the introduction of N. This excellent activity was conducive to the adsorption of oxygen and promoted the formation of the OOH intermediate. This work can serve as an important reference for regulating the electronic structure of MXene to expand the application area in the electrochemical field.