Thermogravimetric insight in the reduction of xCuO – (1-x)MoO3 oxide system (0.1 ≤ x ≤ 0.9) by hydrogen. (April 2021)

• Record Type: Journal Article
• Authors: Jelić, Dijana; Zeljković, Saša; Jugović, Dragana; Mentus, Slavko
• Is Part Of: International journal of refractory metals & hard materials. Volume 96(2021)
• Publication Date: 2021-04
• Subjects: Copper oxide -- Cu-Mo composites -- Hydrogen -- Molybdenum oxide -- Thermogravimetry; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2021.105480
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: The oxide mixtures xCuO-(1-x) MoO3 were synthesized by gel-combustion procedure. The existence of phase mixture CuO + Cu3 Mo2 O9 and MoO3 + CuMoO4 in CuO-rich and MoO3 -rich composition region, respectively, were evidenced. The constant heating rate thermogravimetry in hydrogen atmosphere revealed that the reduction reactions proceed within the two clearly separated temperature regions. On the basis of mass changes, the mechanism of reduction processes was discussed. The measurements revealed considerable inhibition of CuO reduction by MoO3, and huge acceleration of MoO3 → MoO2 reduction step by copper. The particularities found in this system were commented in relation to our similar studies in NiO-MoO3 and CuO-WO3 systems. For particular composition, x = 0.5, existing preferably in form of a-CuMoO4, kinetic parameters of reduction were determined. The composition of oxide mixture influenced the particle size and morphology of resulting metallic Cu-Mo composites. Graphical abstract: Unlabelled Image Highlights: Reduction of CuO-MoO3 system by hydrogen was investigated thermogravimetrically. Low-temperature and high-temperature reduction regions are clearly separated. Metallic Cu accelerates reduction of both MoO3 and MoO2 . Kinetic parameters of equimolar mixture reduction determined by isoconversional method. Homogeneity of Cu-Mo composite is better at lower Cu fractions.