Hledat praktické výstupy

Diesel-like hydrocarbon production through biomass processing is an under extensive study nowadays. Moreover, existing industrial processes require a revision of the technical aspects as they involve the use of noble metal or sulfur-containing catalysts typically applied for hydrotreating reactions. High oxygen content in vegetable oil components and its derivatives is usually considered as a restriction for their direct utilization as fuels. Saturated fatty acids, in particular, stearic acid (SA), are commonly used as model compounds to investigate chemical transformations of biomass when developing new catalytic systems. Catalytic hydrodeoxygenation (HDO), decarboxylation and decarbonylation the most promising approaches for oxygen removal and thus for the upgrading of oxygen-rich feedstock. Easy-to-prepare molybdenum-based materials, with a high potential as catalysts for the HDO of SA towards producing C17 – C18 alkanes, were investigated in this study. Molybdenum nitrides, carbides, and phosphides were prepared by the temperature-programmed reduction method and tested in batch conditions using a Parr autoclave. Their physicochemical and textural properties were analysed using XRD, N2-adsorption, H2-TPR, TEM, and SEM techniques. Comparison of the precursor nature and treatment conditions were performed to obtain the phase purity, thus the high catalytic efficiency of resulting bulk materials. According to the X-ray diffraction analysis, the synthesized samples represented phase-pure Mo2N, Mo2C, and MoP what was achieved mainly through the presence of hexamethylenetetramine in the initial precursor reaction mixture. The total degree of deoxygenation over the fresh catalysts decreased in the order Mo2C > Mo2N > MoP where the carbide reached 91% deoxygenation degree at 98 % SA conversion while reusing the phosphide sample in the second catalytic cycle exhibited >99% at total feedstock conversion. The catalytic performance of the prepared samples was correlated with their structural/textural properties.