Synthesis of Ordered Mesoporous Molecular Sieve-Supported Cobalt Catalyst via Organometallic Complexation for Propane Non-Oxidative Dehydrogenation.

Co-based catalysts have shown great promise for propane dehydrogenation (PDH) reactions due to their merits of environmental friendliness and low cost. In this study, ordered mesoporous molecular sieve-supported CoOx species (CoOx/Al-SBA-15 catalyst) were prepared by one-step organometallic complexation. The catalysts show worm-like morphology with regular straight-through mesoporous pores and high external specific surface area. These typical features can substantially enhance the dispersion of CoOx species and mass transfer of reactants and products. Compared with the conventional impregnation method, the 10CSOC (10 wt.% Co/Al-SBA-15 prepared by the organometallic complexation method) sample presents a smaller CoOx size and higher Co2+/Co3+ ratio. When applied to PDH reaction, the 10CSOC delivers higher propane conversion and propylene selectivity. Under the optimal conditions (625 °C and 4500 h-1), 10CSOC achieves high propane conversion (43%) and propylene selectivity (83%). This is attributed to the smaller and better dispersion of CoOx nanoparticles, more suitable acid properties, and higher content of Co2+ species. This work paves the way for the rational design of high-performance catalysts for industrially important reactions.

Preparation of the methyltriethoxysilane based aerogel monolith with an ultra-low density and excellent mechanical properties by ambient pressure drying.

Methyltriethoxysilane based aerogel monoliths with excellent mechanical properties, an ultra-low density, and a highly efficient thermal insulating property were prepared by an improved simple and environmental-friendly ambient pressure drying process. The morphology, particle size, and nano-pore volume of aerogel monoliths were characterized by scanning electron microscope and nitrogen gas adsorption-desorption analyzer. The elastic modulus of particles in aerogel monoliths and the compressive stress-strain response of aerogel monoliths were estimated based upon experimental data obtained via atomic force microscope and materials testing machine. A structural model is proposed to estimate the critical compressive stress with a structural coefficient being introduced to manifest the microstructural integrity of aerogel monoliths. The mechanism for the low bulk density aerogel monoliths to exhibit a linear stress-strain response and a non-buckling failure mode under the uniaxial compression is discussed.