Asymmetric coordination engineering accelerates the electrochemical nitrate reduction kinetics on metal-organic frameworks

Electrochemical nitrate reduction reaction (ENITRR) offers a prospective strategy for addressing energy crisis and environmental concerns. The enrichment of reactant at the catalytic surface, which is significantly correlated with the catalytic performance, is rarely investigated to reveal the relationship between the performance and structure of the catalyst, especially at the microscopic scale. This study presents a straightforward method for synthesizing asymmetrically coordinated copper-based conjugated metal-organic frameworks (c-MOFs) with a well-defined structural configuration, offering a model to investigate the impact of electronic state and microenvironment on electrocatalytic performance. The Cu-O₂N₂-MOF catalyst exhibits high activity, with Faradaic efficiency of 96.28 % and a yield rate of 6.54 mg h⁻¹ mg_cat⁻¹ toward ENITRR. Both experimental and theoretical results elucidate that the symmetry-breaking strategy can regulates the electronic state and microenvironment of metal active centers, promoting the formation of the *NO₂ intermediate, reducing the energy barriers for ENITRR, and optimizing the d-band center, thus explaining the superior performance of Cu-O₂N₂-MOF. This study offers new insights into the structure-performance relationship of MOFs-based catalysts for ENITRR, providing guidance for the design of symmetry-breaking catalysts for electrocatalytic reactions.