Mechanochemically assisted solid state synthesis, characterization, and catalytic properties of MgWO4
The synthesis of MgWO4 nanopowders was achieved by mechanically activated and following thermal treatment at 850 °C of two mixtures, containing the pure oxides (MgO/WO3) and magnesium carbonate trihydrate and tungsten oxide (MgCO3·3H2O/WO3) as precursors. The obtained samples have been analyzed by the X-ray powder diffraction, infrared spectroscopy (IR), thermal analysis, specific surface area, transmission electron microscopy (TEM, SAED, and XEDS), and X-ray photoelectron spectroscopy. The prepared samples were modified with 0.5 wt% Pd, and the catalytic activities have been measured in reaction of complete oxidation of CO, methane, n-hexane, and toluene. It has been observed that Pd-containing samples with 3 wt% WO3 are more active than the MgWO4/Pd, the most remarkable improvement being achieved in the reaction of toluene combustion. This result is explained by the presence of the palladium in Pd4+ state (as PdO2 particles) due to the stabilization role of the WO3-matrix.
KeywordsTungsten Oxide Conversion Degree MgCO3 Pure Oxide Plug Flow Reactor
The financial support of the National Science Fund, Ministry of Education and Science, Bulgaria, (Contract No. DFNI—T01/6) is greatly acknowledged.
- 17.Borshch AN, Dorokhov YG, Golub AM (1979) For low-temperature modification of MgWO4. Ukr Khim Zh 39:724–726Google Scholar
- 21.Ll JQ, Yang C, Meng JX (2009) Hydrothermal synthesis of MgWO4 and its luminescence. Chin J Lumin 3:327–332Google Scholar
- 24.Im DH, Jee HS, Kim ES (2012) Microwave dielectric properties of ceramic/semicrystalline polymer composites. Jpn J Appl Phys 51:09MD16-09MD20Google Scholar
- 29.Boldyrer VV (2006) Mechanochemistry and mechanical activation of solids. Russ Chem Rev 75:203–216Google Scholar
- 30.Balaz P, Achimovicova M, Balaz M, Billik P, Cherkezova-Zheleva Z, Criado JM, Delogu F, Dutkova E, Gaffet E, Gotor FJ, Kumar R, Mitov I, Rojac T, Senna M, Streletskii A, Wieczorek-Ciurowa K (2014) Hallmarks mechanochemistry: from nanoparticles to technology. Chem Soc Rev 42:7571–7639CrossRefGoogle Scholar
- 41.Hagen J (2006) Industrial catalysis a practical approach. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, pp 227–228Google Scholar
- 42.TOPAS V4: general profile and structure analysis software for powder diffraction data, User’s Manual, Bruker AXS, Karlsruhe, Germany Bruker AXS (2008)Google Scholar
- 45.White WB (1971) Infrared characterization of water and hydroxyl ion in the basic magnesium carbonate minerals. Am Mineral 56:46–53Google Scholar
- 50.Moulder JF, Stickle WF, Sobol PE, Bomben KD (1992) Handbook of X-ray photoelectron spectroscopy. Perkin-Elmer Corporation, Eden PrairieGoogle Scholar