Adsorbate-Driven Restructuring Governs Active-State Evolution in Metal-Based Heterogeneous Catalysis

Abstract Catalytic active sites are traditionally considered as structures formed during synthesis and subsequently modified by adsorbate binding. Increasing operando evidence, however, reveals that adsorbates can actively reorganize catalysts through atomic migration, defect formation, cluster nucleation, alloy segregation, and interfacial reconstruction. Here, we propose adsorbate-driven restructuring as a framework for understanding how reaction environments regulate the generation, stabilization, and catalytic relevance of active states. Adsorbates reshape the catalyst free-energy landscape, stabilize reaction-compatible configurations, and transform the working catalyst into an evolving ensemble of interconverting structures. Catalytic performance is therefore determined not only by intrinsic activity but also by the steady-state populations of accessible states. Through representative examples from metal surfaces, alloys, clusters, and supported nanoparticles, we highlight how reaction environments generate, stabilize, and redistribute catalytically relevant motifs, shifting catalyst design from preserving static sites toward controlling dynamic restructuring pathways.