Ambient temperature electrochemical ammonia synthesis via nitrate reduction reaction (NO3RR) is a promising alternative to the energy-intensive Haber-Bosch process but lacks effective electrocatalysts for practical applications. In this work, MnO2 2D-nanoflakes are anchored onto 2D-MXene Ti3C2Tx, forming a heterogeneous catalyst for NO3RR with an ammonia yield of 14.06 ± 0.48 mg h−1.mgcat−1 at −1.2 V versus reversible hydrogen electrode (vs. RHE) and a Faradaic efficiency (FE) of 85.23 ± 1.62% at −1.0 vs. RHE, along with good stability over six consecutive cycles, with NH3 FE exceeding 75% at −1.0 V vs. RHE in 0.5 M K2SO4 and 0.1 M KNO3 electrolyte. As a cathode in a Zn-NO3− battery with a polished Zn plate from spent Zn-C batteries as anode, it delivers a power density of 0.323 mW cm−2 and NH3 FE of ∼79.9%. This study highlights a highly effective electrocatalyst for NO3RR and its potential in self-powered NH3 production.
