Mesoporous manganese oxides prepared by solution combustion synthesis as catalysts for the total oxidation of VOCs

• Mesoporous manganese oxide catalysts for the total oxidation of VOCs.
• Mn3O4 catalyst showed the highest amount of electrophilic oxygen on the surface.
• FT-IR analysis revealed an abundant population of Brønsted acidic sites on hydrated Mn3O4.
• Long-term stability of Mn3O4 at 310 °C for 10 h at GHSV = 38,000 h−1.

Three mesoporous manganese oxide catalysts (Mn2O3, Mn3O4 and MnxOy) have been prepared, by means of the solution combustion synthesis, and tested for the total oxidation of volatile organic compounds (VOCs; ethylene, propylene, toluene and their mixture). The best results, in terms of the total oxidation of VOCs, were achieved with the Mn3O4 catalyst, which showed the highest amount of electrophilic oxygen on the surface (Oα-species).The most active powder catalyst was then deposited on a cordierite-type monolith through a novel direct synthesis and tested for the total oxidation of the VOCs mixture. The Mn3O4-based monolith exhibited high activity towards the total oxidation of VOCs, which is comparable to that obtained with powdered Mn3O4. The monolithic catalyst showed excellent catalytic activity for the total combustion of the mixture of VOCs (conversion to CO2 = 99.2% ± 0.5) over a time-on-stream of 10 h at 310 °C and no deactivation occurred during this time span.

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