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.

中文翻译：

---

Cu/Cu2O/CuO多级纳米片用于硝酸盐电催化转化为氨

考虑到节能和生态保护，硝酸盐废水电催化还原有价氨（NO ₃ RR）具有广阔的应用前景。尽管如此，多重电子转移和析氢竞争严重阻碍了反应动力学和选择性。本文通过原位电化学重构设计了具有多相界面的Cu/Cu ₂ O/CuO分级纳米片。由垂直扩展的纳米片组成的一维结构可以揭示许多活性位点并促进质子的转移。此外，Cu/Cu ₂ O/CuO之间的电子相互作用和界面效应使得调节Cu d带中心并控制中间体的吸附能成为可能。考虑到这些优点，Cu/Cu ₂ O/CuO分级纳米片在-0.23 V的低过电势下对NO ₃ RR表现出优异的法拉第效率（90.52％）、显着的氨选择性（91.21％）和出色的硝酸盐转化率（89.31％）与 RHE 相比。