Structural evolution of alumina supported Mo-W carbide nanoparticles synthesized by precipitation from homogeneous solution

The synthesis of alumina-supported Mo-W carbide nanoparticles from the propane carburization of precursor metal sulphide, itself, obtained via precipitation from homogeneous solution (PFHS) has been investigated. Carburization temperature and time as well as the temperature-composition and time-temperature interaction effects were also found to be important determinants of the BET surface area, pore volume, surface chemical nature and extent of carburization. Thermogravimetry revealed that the metal sulphide conversion proceeds via a two-stage process involving substitutionary reaction in which S atom is replaced with carbon atom in the metal lattice. SEM images also confirmed that although temperature is detrimental to high surface area, the presence of spherical nanoagglomerates (25-35 nm) is indicative of the high dispersion offered by precipitation from homogeneous solution.