Electrochemical nitrate reduction reaction (NITRR) has emerged as a promising approach for both nitrate contamination removal and ammonia producing in mild ambient conditions. Herein, a novel strategy based on interfacial engineering is proposed to improve the catalytic performance of MoS₂ via introducing few-layer V₂C MXene heterostructure. This explicitly tailored method effectively addresses the challenge of MoS₂ aggregation, while simultaneously inducing transformative changes in the native electron orbitals of Mo active sites in MoS₂. The optimal heterostructure MoS₂@V₂C catalyst emerges with excellent attributes: nitrate removal rate (93%), ammonia selectivity (84%), and Faradic efficiency (80%) at −0.9 V (vs. reversible hydrogen electrode (RHE)) in a low NO₃⁻ concentration. The theoretical research demonstrates the energy barrier of *NO to *NOH is significantly reduced by 0.92 eV after inducing V₂C MXene. Moreover, there is an evident shift in the center of the d-band towards the Fermi level, accompanied by a potent suppression of the hydrogen evolution reaction.

The electrochemical reduction of nitrate to ammonia (ENRA) provides an efficient approach to remove nitrate pollution and achieve ammonia production simultaneously. Herein, inspired by bio-enzyme in denitrifying bacteria, a carbon-coated nickel phosphide (NiPC) nanosheet derived from metal-organic frameworks (MOFs) is proposed as an efficient catalyst for ENRA. Through electron engineering, controllable Ni^δ+ in nickel phosphide is achieved by regulating the degree of phosphating, which enhances its activity for the hydrogenation of nitrate. As the result, Ni^δ+ becomes one of dominating factors determining the efficiency of the ENRA reaction in nickel phosphide. The optimal NiPC catalyst exhibits impressive property toward ENRA: NH₄⁺ Faraday efficiency of 96.68%, NH₄⁺ selectivity of 99.04%, and nitrate conversion rate of 90.43% under low nitrate concentration (200 mg·L⁻¹). This work opens a new avenue for the design of next-generation catalysts through electron engineering for ENRA.