Redirecting surface reconstruction of CoP-Cu heterojunction to promote ammonia synthesis at industrial-level current density
Li Gan, Xiaoxue Zhang, Lei Guo, Muhammad Ajmal, Ru Jia, Xiaolei Guo, Chengxiang Shi, Lun Pan, Faryal Idrees, Xiangwen Zhang, Zhen‐Feng Huang, Guidong Yang, Ji‐Jun Zou
Abstract
The electrochemical reduction of nitrate (NO 3 − RR) represents a compelling approach for the treatment of wastewater, serving as both a sustainable substitute to the energy-intensive Haber-Bosch process and a viable alternative to direct electroreduction of N 2 . However, the process involves multiple electron and proton transfer steps and a complex reaction pathway, leading to low Faraday efficiency and selectivity. Herein, we demonstrated a directional surface reconstruction to generate CoP-Cu/Co(OH) 2 heterojunction for synergistic catalysis of NO 3 − RR. Impressively, a high ammonia generation rate of 9.91 mmol h −1 cm −2 and a Faraday efficiency of 99.2 % can be achieved at an industrial-relevant current density of 2 A cm −2 . Moreover, the catalyst exhibited exceptional durability, maintaining the activity for 110 h under industrial current density. Such outstanding NO 3 − RR performance can be ascribed to the synergistic catalytic effect among the active sites of Cu, CoP and Co(OH) 2 , as well as the excellent stability of self-supported catalyst. Specifically, Cu and CoP sites synergistically promote the conversion of NO 3 − to NO 2 − and NO 2 − to NH 3 . Meanwhile, the partial reconstructed Co(OH) 2 from CoP enhances water dissociation, thereby supplying active hydrogen (*H) essential for NO 3 − RR. When applied to a membrane electrode assembly (MEA) system, CoP-Cu/Co(OH) 2 can deliver satisfactory ammonia production rate with appreciable economic benefits at industrial-level current densities, highlighting its potential for industrial applications.