Insights Into N-coordinated Bimetallic Sites Synergy During NO Selective Catalytic Reduction By CO

The nature of synergistic effect in bimetallic catalysts remains a challenging issue,due to the difficulty in understanding the adjacent interaction between dual metals at atomic level.Herein,a CuFe-N/C catalyst featuring diatomic metal–nitrogen sites was prepared through a sequential ion exchange strategy and applied for the NO selective catalytic reduction by CO（CO-SCR）.The bimetallic CuFe-N/C catalyst exhibits high N₂ selectivity with NO conversion efficiency of nearly 100%over a wide temperature range from 225 to 400℃,significantly higher than their single-component counterparts.Synergistic effect of bimetallic Cu-Fe sites is well revealed by combined in-situ FTIR technique and DFT calculations.Bifunctional Cu-Fe sites are demonstrated not only to provide two different preferential adsorption centers for CO molecule and ONNO intermediate,but also to achieve a complete electron cycle for efficient interfacial electron transfer upon ONNO uptake.The unique electron transfer mechanism stemmed from 4s-3d type electron coupling and different 3d shell filling of Cu(3d¹⁰)and Fe（3d⁶）atoms is presented.These fundamental insights pave the way for the understanding of N-coordinated bimetallic sites synergy and rational design of highly active atomic scale metal catalysts for SCR applications.