Manganese-containing VOC oxidation catalysts prepared in molten salts

• Published in: Applied catalysis. A, General Vol. 368; no. 1; pp. 79 - 86
• Main Authors: Raciulete, Monica, Afanasiev, Pavel
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 31-10-2009; Elsevier
• Subjects: Catalysis; Chemical Sciences; Chemistry; Exact sciences and technology; General and physical chemistry; Manganese; Molten nitrate; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titania; VOC oxidation; Zirconia; Zirconia; VOC oxidation; Titania; Molten nitrate; Manganese; Binary compound; Combustion; Nitrates; Precursor; Supported catalyst; Solid; Zirconium oxide; Optical transmission; Model reaction; Oxidation; Catalytic reaction; Hydrocarbon; Reference; Toluene; Transition element compounds; Transition metal; X ray diffraction; Molten salt; Heterogeneous catalysis; Transmission electron microscopy; Benzene; Benzenic compound; Surface area; Titanium oxide; Catalyst
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2009.08.012

One-pot reactions of MnCl
2 or KMnO
4 with Zr or Ti precursor salts in the NaNO
3–KNO
3 eutectic nitrate melts allow obtaining supported oxide catalysts containing Mn(III, IV) oxide species supported on TiO
2 or ZrO
2 nanoparticles. The solids as obtained possess advantageous textural properties and demonstrate high activity in the total oxidation of aromatics.
Mn-Zr and Mn-Ti supported oxide catalysts have been prepared by means of reactions in molten Na(K)NO
3 fluxes at 500
°C. The solids were characterized using X ray diffraction, textural measurements, optical spectroscopy and transmission electron microscopy. Highly dispersed ZrO
2 and TiO
2 covered with Mn(III, IV) species were obtained from the reaction in the melt. Due to the stabilizing effect of Mn, ZrO
2-based solids with specific surface areas up to 220
m
2/g were obtained. The influence of Mn loading and the nature of precursors on the solids properties were studied. The catalytic properties were studied in the model reactions of total oxidation of benzene and toluene. Molten salt derived solids demonstrated advantageous catalytic activity as compared to the reference catalysts. ZrO
2-supported catalyst prepared using KMnO
4 precursor showed the highest performance for the combustion of both aromatic hydrocarbons with
T
50 values of 236 and 167
°C for benzene and toluene oxidation, respectively.