Structural Dynamic Evolution of Pt Nanoclusters in Ultra-Low-Temperature Methane Combustion with Nitrous Oxide

Tailoring and stabilizing the active sites of supported noble-metal catalysts to a semioxidized state with unsaturated coordination remain a long-standing challenge in heterogeneous catalysis. Herein, we develop a reaction-atmosphere-driven evolution approach for dynamic structural tuning of semioxidized metal sites in supported Pt catalysts. N₂O as an alternative oxidant is used over Pt/TiO₂ in CH₄ combustion to dynamically prompt the transformation of Pt⁰ nanoclusters into Pt^δ+ (0 < δ < 2) nanoclusters. Compared to CH₄ combustion with O₂ that inclines to overoxidize Pt⁰, the catalytic activity of CH₄-N₂O combustion is distinctly boosted, achieving complete CH₄ combustion at only 200 °C, outperforming the state-of-the-art catalysts using O₂ as the oxidant. Computational and experimental studies validate that N₂O triggers less electron transfer from Pt than from O₂, thereby facilitating the formation and preservation of Pt^δ+ species during CH₄ combustion. The newly emerged semioxidized Pt^δ+ species with oxygen-deficient coordination structures simultaneously enhance lattice oxygen activation and the first C-H bond dissociation of CH₄, contributing to ultralow temperature activity. Our work demonstrates that modulating the reaction atmosphere to achieve the structural dynamic evolution of semioxidized metal sites can provide new strategies for designing highly efficient catalysts for low-temperature CH₄ combustion.