Thermal analysis and xrd studies on catalyst supports of potassium tungsten bronze and potassium magnesium titanium oxide

• Published in: Thermochimica acta 1989-10, Vol.152 (1), p.203-213
• Main Authors: Mirza, M.T., Walls, J.R., Jayaweera, S.A.A.
• Format: Article
• Language: English
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/0040-6031(89)85390-0

Two types of mixed oxide compounds (K xWO 3 and K xMg yTi 1-yO 2), both with high electrical conductivity are described. Their potential use as catalytic materials for cracking of hydrocarbons in a reactor powered by electromagnetic energy is investigated. In particular the heating rates of these materials in an R.F. reactor are reported. Structural characterisation of the phases was achieved by XRD. It was found that by altering the value of x in the range 0.2 < x < 0.8 the structure changed from hexagonal to tetragonal. The KMgTiO 2 structure was of the hollandite type. Simultaneous TG and DTA were carried out to characterise the chemical processes involved. Phase changes were investigated over the range 25–800 °C, by heating the samples to different temperatures and by carrying out XRD. Phase stabilities and decomposition reactions of the two compounds are investigated. A comparison between thermal analysis data and electrical conductivity measurements concerning the phase changes hi these materials is described.