In Situ Generation of High-Loading Asymmetric Metal Cluster Catalysts via 2D Confinement for Enhanced Electrocatalysis

Fully exposed atomically dispersed metal cluster (ACs) catalysts offer near-100% atom utilization and exceptional catalytic activity, yet achieving high loading and controlled synthesis remains challenging. To address this issue, leveraging high-temperature calcination of porous C₂N and its inherent 2D confinement effect, asymmetric 3d metal clusters are in situ anchored within cavity centers (asymmetric MACs/C₂N), yielding high-loading (12.8 wt.%), fully exposed asymmetric Cu ACs. For the model nitrate reduction (NO₃RR), CuACs/C₂N exhibit exceptional catalytic performance, achieving a Faradaic efficiency of 97.9% and an NH₃ yield of 0.66 mg h⁻¹ cm⁻² at −0.6 V. Spectroscopic analysis and theoretical calculations indicate that the dynamic evolution of the asymmetric Cu₅N₂ active sites during the reaction significantly lowers the reaction energy barrier. This strategy is further applicable to 4d palladium- and 5d platinum-based systems (PdACs/C₂N, PtACs/C₂N), demonstrating its broad potential. The development of high-loading asymmetric atomic clusters offers a novel and effective approach for constructing highly active catalytic sites in advanced electrocatalysts.