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

Abstract

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 PtO2 metallene oxide. By employing rutile TiO2 and rutile SnO2 supports with distinct lattice parameters, we achieve epitaxial growth of PtO2 metallene oxide layers with controlled strain states, where the larger-lattice SnO2 substrate imposes biaxial tensile strain on PtO2. The tensile-strained PtO2/SnO2 exhibits a reconfigured Pt-O electronic environment that simultaneously improves structural resilience and enhances the intrinsic reactivity of PtO2, delivering markedly improved methane oxidation performance with a T90 of 370 °C (versus 434 °C for PtO2/TiO2 and 469 °C for PtOx/Al2O3) 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.

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