Epitaxial-strain engineering of supported tensile noble metallene oxides for enhanced oxidation catalysis

Supported two-dimensional noble metal oxides (metallene oxides) hold great promise for heterogeneous catalysis owing to their maximized surface exposure and tunable electronic structures. However, their high surface energy and low oxidation potentials make them intrinsically unstable under reaction conditions. Here, we report an epitaxial strain strategy to stabilize and modulate the electronic structure of supported PtO 2 metallene oxide. By employing rutile TiO 2 and rutile SnO 2 supports with distinct lattice parameters, we achieve epitaxial growth of PtO 2 metallene oxide layers with controlled strain states, where the larger-lattice SnO 2 substrate imposes biaxial tensile strain on PtO 2 . The tensile-strained PtO 2 /SnO 2 exhibits a reconfigured Pt–O electronic environment that simultaneously improves structural resilience and enhances the intrinsic reactivity of PtO 2 , delivering markedly improved methane oxidation performance with a T 90 of 370 °C (versus 434 °C for PtO 2 /TiO 2 and 469 °C for PtO x /Al 2 O 3 ) and <1% conversion loss over 38 h under both dry and wet conditions. Moreover, this epitaxial strain strategy is generalizable to other environmentally relevant oxidation reactions and rutile-type noble metal oxides, establishing tensile strain imposed by epitaxial lattice matching as a general principle for stabilizing atomically thin noble metal oxides while tuning their electronic structure.