Heterogeneous 2D/2D MnO/MXene catalyst for nitrate-to-ammonia electrochemical reduction and Zn-nitrate battery behavior.

Ambient temperature electrochemical ammonia synthesis via nitrate reduction reaction (NORR) is a promising alternative to the energy-intensive Haber-Bosch process but lacks effective electrocatalysts for practical applications. In this work, MnO 2D-nanoflakes are anchored onto 2D-MXene TiCT, forming a heterogeneous catalyst for NORR with an ammonia yield of 14.06 ± 0.48 mg h.mg 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 NH FE exceeding 75% at -1.0 V vs. RHE in 0.5 M KSO and 0.1 M KNO electrolyte. As a cathode in a Zn-NO battery with a polished Zn plate from spent Zn-C batteries as anode, it delivers a power density of 0.323 mW cm and NH FE of ∼79.9%. This study highlights a highly effective electrocatalyst for NORR and its potential in self-powered NH production.