High‐Energy‐Facet‐Oriented Mesoporous Single‐Crystal Metal Oxides for Selective Oxidation Catalysis

Mesoporous single‐crystal metal oxides are highly attractive for heterogeneous catalysis because they combine high surface accessibility with long‐range lattice coherence; however, their synthesis remains fundamentally challenging due to the thermodynamic incompatibility between crystallization and pore formation. Here we report a template‐free, energy‐driven facet‐oriented crystallization strategy that enables the formation of mesoporous single‐crystal metal oxides with tunable pore architectures and exposed high‐energy facets. Polyvinylpyrrolidone functions simultaneously as a pore maintainer and surface‐energy regulator, preserving mesoporosity while selectively stabilizing high‐energy facets to direct single‐crystal growth. The method is applicable to multiple oxides, including Co 3 O 4 , MgO, NiO, and mixed‐metal systems. As a representative example, mesoporous single‐crystal Co 3 O 4 with preferentially exposed (111) facets exhibits outstanding performance in the selective oxidation of aromatic alkanes, achieving up to 99% conversion and selectivity under mild conditions. Experimental and theoretical analyses suggest that the synergy between mesoporosity and active‐facet exposure enhances reactant adsorption, oxygen activation, and reaction kinetics, providing a general design principle for crystallographically defined porous catalysts.