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

Abstract

ABSTRACT 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.