In-situ scalable fast fabrication of Cu-Cu2+1O nanorods for highly efficient electrocatalytic reduction into ammonia under neutral medium

Abstract

The development of a highly efficient and durable electrocatalyst for nitrate reduction reaction (NO3RR) wastewater valorization to ammonia (NH3) is a promising strategy. However, it is challenging to design scalable low-cost electrocatalysts with high activity, high selectivity, and long-term stability by a facile and simple method. Herein, we construct this scalable Cu-based nanoarray with muti-oxidation states grown directly on nickel foam (NF) substrate (Cu2+1O@Cu/NF) using a facile molten salt method combined in-situ electrochemical reduction. The as-prepared Cu2+1O@Cu/NF nanoarrays reveal a high NH3 yield of 20.14 mg h−1 cm−2 at −0.95 V vs. a reversible hydrogen electrode (vs. RHE), Faradaic efficiency of 99.38% at −0.55 V vs. RHE in the neutral potassium phosphate (PBS) buffer solution with 50 mM NaNO3, which is ascribed to its electron redistribution with abundant oxygen vacancies and favorable charge/mass transfer.