Interface Modification of Single Atom‐Nanocluster Synergistic Sites to Break the Activity‐Selectivity‐Stability Trade‐Off in Selective Hydrogenations

Abstract Synergistic sites (M 1 +M n ) integrating single atoms (M 1 ) and clusters (M n ) exhibit tremendous promise for overcoming linear scaling relationships. However, metal entities spatial segregation within synergistic sites impedes the overall optimization and structure‐property analysis, and the support interface of the M 1 and M n sites critical for intermediate adsorption‐transfer kinetics has yet unexplored. Here, for the first time, interfacial modification strategy is proposed to modulate the interface and electronic structure of M 1 +M n sites. This is systematically altered that the interface of Pd 1 +Pd n sites from hydroxyapatite (HAP) to nitrogen‐doped carbon‐modified HAP (NC/HAP) and pure NC, with all sites maintaining the comparable size and content. In the semi‐hydrogenation of alkynes, volcano‐type correlations between Pd 1 +Pd n sites with varying interfaces and hydrogenation activities are observed, peaking for those supported on NC/HAP. The obtained Pd 1 +Pd n @NC/HAP exhibits superior activity for alkynol‐to‐enol conversion, achieving a formation rate up to 3707.7 mol mol Pd −1 h −1 while maintaining 97.2% selectivity. Comprehensive investigations propose d‐band center of Pd 1 +Pd n sites with different interfaces as a descriptor to elucidate the volcano‐type correlation for various selective hydrogenation reactions. Interfacial modification of Pd 1 +Pd n sites can optimize their electronic structure, adeptly managing substrates adsorption–desorption kinetic and interface H‐spillover between segregated metal sites, thereby breaking − the activity‐selectivity‐stability trade‐off.