One-pot synthesis of VO x /Al 2 O 3 as efficient catalysts for propane dehydrogenation.

Vanadium oxides, as highly efficiently catalysts, are widely applied in various catalytic reactions, such as the dehydrogenation of light alkanes and epoxidation of alkenes. In this paper, a series of VO x /Al 2 O 3 catalysts were fabricated by the 1-pot method for catalytic propane dehydrogenation. The results indicated that the VO x /Al 2 O 3 catalysts with loading of 10 wt.% vanadium exhibited optimized catalytic performance. The as-prepared catalysts were characterized by N 2 adsorption-desorption, XRD, TEM, H 2 -TPR, and XPS to explore the texture properties, morphology, and electronic environment of vanadium. In addition, several vanadium catalysts were also prepared by the incipient wetness impregnation (IWI) method to compare their catalytic performance with the 1-pot synthesized catalysts. The catalysts synthesized by the 1-pot method exhibited higher selectivity of propylene and longer catalyst lifetime at high propane conversion when compared to the counterpart synthesized by the IWI method.

Rapid synthesis of hierarchical SSZ-13 zeolite microspheres via a fluoride-assisted in situ growth route using aluminum isopropoxide as aluminum source.

Hierarchical SSZ-13 zeolite microspheres were quickly synthesized by adding a small quantity of hydrofluoric acid in the starting gel using aluminum isopropoxide as aluminum source. The as-synthesized hierarchical SSZ-13 crystals with high crystallinity, pore volume and external surface area were obtained within 12 h, whereas a much longer time (144 h) was necessary to synthesize a fully crystalline zeolite in a fluorine free system. The obtained hierarchical SSZ-13 catalysts showed excellent MTO performance together with considerably prolonged catalytic lifetime and improved selectivity of light olefins in comparison with the conventional microporous SSZ-13.

Three-dimensionally ordered macro-mesoporous CoMo bulk catalysts with superior performance in hydrodesulfurization of thiophene.

The introduction of surfactants during the fabrication of hydrodesulfurization catalysts could not only tune the microstructure but also promote the dispersion of active components. In this work, CoMo bulk catalysts with the hierarchical structure of three-dimensionally ordered macro-mesopores were successfully fabricated by using a colloidal crystal template with the addition of PEG 400 and/or F127 surfactants. The obtained samples were characterized by various techniques, and the possible mechanism of the structure formation was also discussed. The characterization and evaluation results reveal that the addition of surfactants can promote the formation of the mesopores (3-4 nm) inside the macroporous walls of these bulk catalysts, which is essential for the increase of catalyst surface area, and the active sites for reaction. The CoMo-PF-1 catalyst displayed superior catalytic performance for thiophene hydrodesulfurization with the thiophene conversion of 99.4% under 1 MPa at 360 °C, which is much higher than that (77.8%) at 0.1 MPa. This result is even comparable to our previous report with the thiophene conversion of 99.2% over the 3DOM CoMo catalyst under 3 MPa.

Template-Free Synthesis of Hierarchical SSZ-13 Microspheres with High MTO Catalytic Activity.

Hierarchical SSZ-13 microspheres, with abundant mesoporous channels, have been successfully synthesized by addition of calcined SSZ-13 crystals in the starting gel in the absence of any organic templates. This strategy not only remarkably reduces the production cost and environmental pollution, but also significantly decreases the crystallization time as well as evidently reducing the zeolite crystal sizes in many cases. The synthesized sample was characterized by XRD, BET, ICP, SEM, TEM, TG, and NH3 -TPD, which indicates that the organic template free synthesized SSZ-13 exhibits high crystallinity, textural properties, and acidity. Moreover, the synthesized hierarchical SSZ-13 catalyst shows outstanding performance in the methanol-to-olefin (MTO) reaction, with slightly higher ethylene plus propylene selectivity and prolonged catalyst lifetime as compared to the templated SSZ-13 catalyst.