Conversion of nitrates (NO3−) to ammonia (NH3) by electrocatalysis is a sustainable approach for resource utilization from wastewater. Nonetheless, this conversion is often constrained by sluggish mass transfer. In this study, we developed a laminar membrane using Pd-Cu bimetal functionalized 2D MXene (Ti3C2Tx) to accelerate the mass transfer during NO3− reduction. The resulting membrane exhibited outstanding NO3−-N removal efficiency (99.0 ± 0.5 %) and NH4+-N selectivity (74.1 ± 0.6 %), and maintained excellent NO3−-N removal efficiency with various influent NO3− concentrations. Its nitrate reduction performance was relatively stable even in low-conductivity influents similar to surface water, presence of dissolved oxygen (DO) or after membrane fouling. The NO3−-N removal rate in the electrocatalytic filtration system was 11 times that without filtration, attributed to a ten-fold improvement in the mass transfer constant (km) with filtration and the increased active sites for NO3− reduction by 2D MXene. The filtration process ensured a higher NH4+-N selectivity by preventing the re-oxidation of NH4+-N on anode. The mechanism of nitrate reduction on the laminar membrane was predominantly direct reduction, and the spatial distribution analysis of atomic hydrogen (H*) demonstrated that it was difficult for H* to participate in nitrate reduction reaction due to the strong adsorption of H* on the membrane. Theoretical calculations suggested that Pd-Cu bimetal could greatly diminish the energy barriers for NO3− to NH4+ and enhance the conversion efficiency. This finding offers valuable insights for developing efficient and robust nano-laminar membranes aimed at nitrate removal and ammonium production in water.