Boosting Electrocatalytic Nitrate Reduction to Ammonia on a Hierarchical Nanoporous Ag,Ni-Codoped Cu Catalyst via Trimetallic Synergistic and Nanopore Enrichment Effects
Yuhuan Cui, Changning Sun, Yuexuan He, Zixuan Feng, Guopeng Ding, Qingqing Dai, Tonghui Wang, Zhili Wang, Qing Jiang
Abstract
The electrochemical nitrate (NO 3 – ) reduction reaction (NO 3 – RR) offers a promising route for NO 3 – wastewater treatment and sustainable ammonia (NH 3 ) synthesis. However, the reaction still faces the challenges of unsatisfactory productivity and selectivity. Herein, we report a hierarchical nanoporous Ag,Ni-codoped Cu (np Ag,Ni-Cu) catalyst that exhibits a high NH 3 Faradaic efficiency of 98.5% with an attractive NH 3 yield rate of 41.1 mg h –1 mg cat –1 at −0.2 V vs RHE for the NO 3 – RR. Density functional theory calculations and molecular dynamics simulations suggest that the excellent performance of np Ag,Ni-Cu results from a trimetallic synergistic effect and nanopore enrichment/confinement effect, in which the codoping of Ni and Ag into Cu can enhance NO 3 – adsorption, prevent *NO 2 desorption, and suppress the hydrogen evolution reaction, while nanopores can promote NO 3 – accumulation on the internal surface of nanopores and confine the reaction intermediates within the nanopores for a deeper NO 3 – electroreduction.