Synergistic integration of copper and cobalt-MOF for high-efficiency electrocatalytic nitrate reduction to ammonia

The electrocatalytic nitrate reduction reaction (NO 3 - -RR) offers an attractive approach for mitigating water pollution and facilitating nitrogen cycling and hydrogen economy integration. However, this method involves sluggish eight-electron transfer process accompanied by significant competing reactions. Consequently, developing efficient electrocatalysts that provide excellent catalytic activity and selectivity is particularly important. Herein, we develop a bimetallic catalyst , Cu@Co-MOF-74, by modifying Co-MOF-74 with copper ions through simple immersion. The resulting catalyst exhibits high efficiency and selectivity for NO 3 - -RR, achieving an ammonia production efficiency of 307.98 mmol/h/g cat and a Faraday efficiency of 84.01 % at −0.88 V vs. RHE. The synergistic effect of the cobalt and copper sites enhances electron transfer , improving both ammonia yield and Faraday efficiency. 15 N isotope labeling experiments demonstrate that the formation of NH 3 originated from the NO 3 - -RR process. This work presents a novel approach for developing high-performance electrocatalysts for sustainable NH 3 production. • A bimetallic Cu@Co-MOF-74 catalyst was synthesized via simple immersion. • The synergy between Cu and Co sites enhances electron transfer , optimizing the reaction pathway. • Cu@Co-MOF-74 exhibits excellent ammonia yield and selectivity. • A NH 3 yield of 307.98 mmol/h/g cat and Faraday efficiency of 84.01 % at −0.88 V vs. RHE are achieved.