(230p) Synthesis of Molybdenum Oxide Particles By Ultrasonic Spray Pyrolysis and Their Partial Oxidation Activity

Molybdenum oxides exist mainly in two forms: MoO₂ and MoO₃. MoO₃ has been used as a semiconductor, a field-emitter, an electrochromic material, photochromic material, and a gas sensor. MoO₂ exhibits metal-like electronic conductivity because of the existence of delocalized electrons in its valence band. Both MoO₃ and MoO₂ have been used as a catalyst in hydrocarbon reforming processes. In particular, MoO₂ has attracted a lot of attention due to coke resistance and sulphur tolerance during the partial oxidation of hydrocarbons. Although commercial MoO₂ has a very small BET surface area (< 10 m²/g), some researchers reported solvothermal synthesis of MoO₂ nanoparticles with a high BET surface area of about 50 m²/g. However, the yield of MoO₂ nanoparticles by solvothermal synthesis was less than 1 g/batch. In this study, we developed a large scale production process for molybdenum oxides by ultrasonic spray pyrolysis. The particle size and phase structure of the product molybdenum oxides were affected by precursor concentration, pyrolysis temperature, carrier gas flow rate, etc. As-synthesized MoO₂ particles were analyzed by BET, XRD, EDX, TGA, and FT-IR. Partial oxidation reaction was studied to test the catalytic performance of the as-synthesized MoO₂ using n-dodecane as a fuel which is a model compound of bio-diesel. The effect of O₂/C ratio, reaction temperature, and weight-hourly space velocity (WHSV) on the conversion and H₂ production were systematically investigated. H₂ and CO yields, and carbon conversion over as-synthesized MoO₂ were calculated and compared with those over commercial one. The as-synthesized MoO₂ particles showed promising reforming performance without any coke formation.