Interface Engineering of the Cu 1.5 Mn 1.5 O 4 /CeO 2 Heterostructure for Highly Efficient Electrocatalytic Nitrate Reduction to Ammonia.

The electrochemical nitrate reduction reaction (NO 3 RR) is considered a sustainable technology to convert the nitrate pollutants to ammonia. However, developing highly efficient electrocatalysts is necessary and challenging given the slow kinetics of the NO 3 RR with an eight-electron transfer process. Here, a Cu 1.5 Mn 1.5 O 4 (CMO)/CeO 2 heterostructure with rich interfaces is designed and fabricated through an electrospinning and postprocessing technique. Benefiting from the strong coupling between CMO and CeO 2 , the optimized CMO/CeO 2 -2 catalyst presents excellent NO 3 RR performance, with NH 3 Faraday efficiency (FE) up to 93.07 ± 1.45% at -0.481 V vs reversible hydrogen electrode (RHE) and NH 3 yield rate up to 48.06 ± 1.32 mg cm -2 h -1 at -0.681 V vs RHE. Theoretical calculations demonstrate that the integration of CeO 2 with CMO modulates the adsorption/desorption process of the reactants and intermediates, showing a reduced energy barrier in the rate determination step of NO* to N* and achieving an outstanding NO 3 RR performance.