A Copper-Zinc Cyanamide Solid-Solution Catalyst with Tailored Surface Electrostatic Potentials Promotes Asymmetric N-Intermediate Adsorption in Nitrite Electroreduction.

The electrocatalytic nitrite reduction (NORR) converts nitrogen-containing pollutants to high-value ammonia (NH) under ambient conditions. However, its multiple intermediates and multielectron coupled proton transfer process lead to low activity and NH selectivity for the existing electrocatalysts. Herein, we synthesize a solid-solution copper-zinc cyanamide (CuZnNCN) with localized structure distortion and tailored surface electrostatic potential, allowing for the asymmetric binding of NO. It exhibits outstanding NORR performance with a Faradaic efficiency of ∼100% and an NH yield of 22 mg h cm, among the best for such a process. Theoretical calculations and in situ spectroscopic measurements demonstrate that Cu-Zn sites coordinated with linear polarized [NCN] could transform symmetric [Cu-O-N-O-Cu] in CuNCN-NO to a [Cu-N-O-Zn] asymmetric configuration in CuZnNCN-NO, thus enhancing adsorption and bond cleavage. A paired electro-refinery with the CuZnNCN cathode reaches 2000 mA cm at 2.36 V and remains fully operational at industrial-level 400 mA cm for >140 h with a NH production rate of ∼30 mg h cm. Our work opens a new avenue of tailoring surface electrostatic potentials using a solid-solution strategy for advanced electrocatalysis.