Optimization of the synthesis of alpha-MoO3 nanoribbons and hydrodesulfurization (HDS) catalyst test.

An optimized process for synthesis of alpha-MoO3 nanoribbons characterized by uniform morphology and composition was carried out. The optimized process turned out to be the aging of a precursor of an aqueous solution of ammonium heptamolybdate for a week under constant stirring at 333 K; followed by hydrothermal treatment for 36 h up to 48 h at 473 K. The dimensions of the nanoribbons were between 5 and 10 microm in length and a width between 100 and 600 nm. The thickness was between 60 and 200 nm. This material was tested for hydrodesulfurization (HDS) of dibenzothiophene (DBT) by in situ activation and showed its catalytic activities to be similar to those of unsupported MoS2 catalysts. The structure and morphology of these materials was characterized by analytical transmission electron microscopy, scanning electron microscopy, and X-ray diffraction using the Rietveld method to determine the quantitative crystallographic phases. A chemical semiquantitative analysis was carried out by energy dispersive spectroscopy and a qualitative analysis was carried out by electron energy loss spectroscopy.