Crystal phase-driven electronic metal-support interactions in Ru/Nb₂O₅ catalysts enable efficient low-temperature acetone oxidation

Efficient catalytic oxidation of oxygenated volatile organic compounds (OVOCs) at low temperatures remains challenging due to insufficient oxygen activation and the accumulation of partially oxidized intermediates. Modulating electronic metal-support interactions (EMSIs) offers a promising strategy to overcome these limitations by tailoring interfacial electronic structures and oxygen activation capability. Here we show that crystal phase engineering of Nb₂O₅ provides a powerful approach to optimize EMSIs in Ru-based catalysts for OVOCs oxidation. The Ru/T-Nb₂O₅ (orthorhombic) catalyst achieves 90% acetone conversion at just 209 °C, outperforming Ru/TT-Nb₂O₅ (pseudohexagonal) catalyst. Spectroscopic analyses combined with density functional theory calculations reveal that the T-phase Nb₂O₅ support induces stronger interfacial charge transfer from Ru to support, stabilizing electron-deficient Ru^δ+ species and markedly lowering the oxygen vacancy formation energy. The resulting high density of surface oxygen vacancies enhances oxygen activation and strengthens acetone adsorption at the interfacial Ru−Nb₂O₅ sites. Surface mechanism investigations identify aldehydes and carboxylic acids as key intermediates and show that the Ru/T-Nb₂O₅ catalyst accelerates their deep oxidation while suppressing intermediate accumulation at low temperature. These findings establish a direct correlation between support crystal phase and interfacial electronic structure, providing a general strategy for designing highly efficient catalysts in OVOCs purification.