Cu/Cu₂O/CuO Hierarchical Nanosheets for Electrocatalytic Conversion of Nitrate to Ammonia

Abstract

Considering energy preservation and ecological conservation, the electrocatalytic reduction of nitrate wastewater to valuable ammonia (NO3RR) has broad application prospects. Nonetheless, multiple electron transfers and hydrogen evolution competition severely hinder the reaction kinetics and selectivity. Herein, Cu/Cu2O/CuO hierarchical nanosheets with a multiphase interface was designed by in situ electrochemical reconstruction. The 1D structure composed of vertically expanded nanosheets can reveal numerous active sites and facilitate the transfer of protons. Additionally, the electronic interaction and interface effect among Cu/Cu2O/CuO make it possible to regulate the Cu d band center and control the adsorption energies of the intermediates. Considering these benefits, Cu/Cu2O/CuO hierarchical nanosheets demonstrated superior Faraday efficiency (90.52%), remarkable ammonia selectivity (91.21%), and outstanding nitrate conversion (89.31%) for NO3RR at a low overpotential of −0.23 V vs RHE.

CuCo2O4/CuO Heterostructure with Oxygen Vacancies Induced by Plasma for Electrocatalytic Nitrate Reduction to Ammonia

“…Ammonia (NH 3 ) is a crucial nitrogen-containing chemical widely used in various industries, primarily in the production of nitrogen-based fertilizers, plastics, refrigerants, and dyes. − It is also regarded as a green, clean energy source due to its mild combustion products and high energy density. Presently, the dominant industrial ammonia production method is the Haber-Bosch (H–B) process, which requires high temperatures (400–500 °C) and high pressures (150–300 atm) − and leads to massive fossil energy consumption and carbon dioxide emissions. , Given the dwindling reserves of fossil fuels and the escalating environmental concerns, it is urgent to develop an innovative alternative technology to displace the conventional H–B process for ammonia synthesis . As is known, NO 3 – has a higher solubility in water compared to N 2 .…”