Asymmetric metal-nitrogen-carbon catalysts: asymmetric structures and electrocatalytic superiority

Asymmetric metal-nitrogen-carbon catalysts (AMNCs) introduce asymmetry into the local coordination environment of metal active centers by disrupting the conventional symmetric coordination structure, thereby offering a new strategy for the design of high-performance electrocatalysts. The asymmetric structure of AMNCs can significantly optimize the adsorption behavior of reaction intermediates, enhance the stability and selectivity of the catalyst, and improve the tunability of catalytic performance, positioning AMNCs as one of the most advanced types of electrocatalysts currently available. This article systematically reviews the structural characteristics of AMNCs and their unique advantages, as well as the superior performance conferred by such asymmetric structures in various electrocatalytic applications, including electrocatalytic reduction, electrocatalytic coupling, and electrocatalytic oxidation. Focusing on the challenges associated with the synthetic chemistry of the asymmetric structure in AMNCs, this review systematically compares and analyzes mainstream preparation methods such as pyrolysis, template methods, impregnation, and deposition. Additionally, it discusses emerging strategies, including pyrolysis-free synthesis, with the aim of providing a reference for establishing the "structure-activity relationship" that bridges the distinctive asymmetric architecture of AMNCs with their superior electrocatalytic performance.