Enhancing Deep Mineralization and Chlorine Resistance in Methyl Ethyl Ketone Destruction by Taming Synergy of WO_<i>x</i> and Pd Sites

Accelerating deep oxidation while restraining the hazardous intermediate formation remains a great challenge in oxygenated volatile organic compounds (OVOCs) catalytic purification. Herein, we found that the modulation of electronic metal–support interactions (EMSIs) in Pd/WOx/Al2O3 catalysts significantly facilitates the deep oxidation of methyl ethyl ketone (MEK) and markedly enhances the CO2 selectivity. Over the Pd/WOx/Al2O3 catalyst, 90% of MEK can be fully oxidized at just 140 °C with a low apparent activation energy (Ea) of 19.65 kJ·mol–1, much superior to that of the commercial Pd/Al2O3 catalyst (Ea of 80.81 kJ·mol–1). The EMSIs promote charge redistribution through the unified Pd-WOx sites, which modulates the d-band structure of highly dispersed Pd sites and strengthens the adsorption and activation of reactants. The positively charged Pd2+ species are dominant in activating MEK molecules at low temperatures, and the stretched W–O bonds enhance the activation of lattice oxygen species to participate in subsequent oxidation, ensuring the rapid total oxidation of MEK molecules via the Mars-van Krevelen mechanism. Furthermore, the bifunctional Pd-WOx sites can also facilitate the dissociation of H2O and CH2Cl2 molecules, enhancing the water-vapor and chlorine resistance of the Pd/WOx/Al2O3 catalyst, which expands the potential toward practical applications. This work sheds significant guidance for researchers to engineer efficacious catalysts toward industrial OVOCs deep elimination.