VOCs combustion catalysed by platinum supported on manganese octahedral molecular sieves

In this work a manganese oxide in the form of octahedral molecular sieve (OMS-2, also called cryptomelane) has been synthesized and used as catalyst and support for Pt. The catalysts were tested and compared with Pt-Al2O3 in the combustion of methyl-ethyl-ketone (MEK), toluene, ethyl acetate and a mixture of toluene and ethyl acetate. Bare OMS-2 was significantly active for the combustion of the oxygenated VOCs and in the case of MEK partial oxidation product was detected at intermediate conversion levels. Platinum on OMS-2 showed high dispersion and improved the activity for toluene oxidation, showing a performance better than that of Pt-Al2O3. As for the VOCs mixture, Pt-OMS-2 presented the highest combustion activity due to the coexistence of active sites for the total oxidation of both aromatic and oxygenated VOCs. Competitive adsorption effects were not observed with this catalyst that achieved complete conversion of 1000 mg C/m3 of VOCs at temperatures below 260 °C (1200 mg C gcatalyst−1 h−1).

Partial conversion of toluene and ethyl acetate in the VOCs mixture (B).Figure optionsDownload as PowerPoint slideHighlights
► OMS-2 has been synthesized and used as catalyst and support for Pt.
► Pt-OMS-2 showed high dispersion and improved the activity for toluene oxidation.
► Pt does not improve the performance of OMS-2 for the oxygenated VOCs combustion.
► In Pt-OMS-2 active sites coexistence for aromatic and oxygenated VOCs combustion.