Abstract
Ambient temperature electrochemical ammonia synthesis via nitrate reduction reaction (NO(3)RR) is a promising alternative to the energy-intensive Haber-Bosch process but lacks effective electrocatalysts for practical applications. In this work, MnO(2) 2D-nanoflakes are anchored onto 2D-MXene Ti(3)C(2)T(x), forming a heterogeneous catalyst for NO(3)RR with an ammonia yield of 14.06 ± 0.48 mg h(-1).mg(cat) (-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 NH(3) FE exceeding 75% at -1.0 V vs. RHE in 0.5 M K(2)SO(4) and 0.1 M KNO(3) electrolyte. As a cathode in a Zn-NO(3) (-) 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 NH(3) FE of ∼79.9%. This study highlights a highly effective electrocatalyst for NO(3)RR and its potential in self-powered NH(3) production.