Strategies for Template-Free Synthesis of Mesoporous Metal Catalysts with Surface-Clean Sites

Conspectus Mesoporous metals, characterized by interconnected pore networks, high specific surface area, and exceptional mass transport properties, epitomize the pinnacle of catalyst design. These attributes are critical for fully exposing active sites and enabling rapid diffusion of reactants and products, particularly during demanding electrochemical and chemical transformations. Historically, synthesizing such intricate metallic nanostructures has long centered predominantly on the templated approaches. This involves using soft templates and/or hard templates to define the mesopore architecture. While effective for mesopore generation, the mandatory template removal step imposes a critical limitation to surface contamination. Residual surfactant-derived species, carbonaceous deposits, or silica fragments persistently coat on metal surfaces, obscuring catalytically active sites, altering their electronic structures, and impeding reactant accesses. Such contamination fundamentally undermines the intrinsic catalytic potential of metals. Consequently, the development of template-free synthetic strategies capable of directly generating mesoporous metals while preserving atomically clean surfaces has emerged as a pressing imperative and transformative frontier in catalysis science. This Account critically examines the burgeoning area of template-free methodologies for preparing mesoporous metals with surface-clean sites. The focus centers squarely on three principal template-free synthetic routes: metal oxide atomic reconstruction, metal salt thermal decomposition, and dealloying. These routes inherently avoid surface impurities by eliminating templates. Crucially, we dissect the mechanistic links between these synthetic routes and formation of surface-clean sites, emphasizing how the absence of template residues directly translates to enhancing catalytic activity and stability and optimizing selectivity. This work not only addresses a critical gap by offering a systematic analysis of template-free synthesis of mesoporous metals but also establishes a structure–property paradigm for rational design of highly active mesoporous metal catalysts. This paves the way for scalable applications in clean energy technologies and carbon neutrality initiatives, positioning surface-clean mesoporous metals as an essential platform for sustainable catalysis.