Synthesis of Ni promoted molybdenum dioxide nanoparticles using solvothermal cracking process for catalytic partial oxidation of n-dodecane

Abstract

Ni promoted MoO₂ nanoparticles were synthesized by combining spray pyrolysis and solvothermal cracking process. First, polycrystalline MoO₃ microparticles were prepared by spray pyrolysis at 600 °C. Then nano-sized Ni-MoO₂ particles were formed by solvothermal cracking process after adding Ni precursor, which disassembled polycrystalline MoO₃ microparticles into crystalline grains by thermal expansion and shattered them into Ni-MoO₂ nanoparticles by the subsequent solvothermal polyol reduction process. TPR profiles of Ni-MoO₂ nanoparticles presented the decrease of reducibility of MoO₂ with addition of Ni promoter. Catalytic partial oxidation of n-dodecane was conducted at various temperatures from 450 °C to 850 °C using Ni-MoO₂ nanoparticles and pure MoO₂ nanoparticles. H₂ yield of all the Ni-MoO₂ nanoparticles was higher than that of pure MoO₂ nanoparticles at 850 °C. Specially, 7 and 10 mol% Ni-MoO₂ nanoparticles showed desirable catalytic performance of ca. 60% of H₂ yield. This is mainly attributed to the existence of polymolybdate with addition of Ni and Ni²⁺ species partly located in the polymolybdate layer without formation of bulk Ni phase.