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BET theory
About: BET theory is a research topic. Over the lifetime, 9046 publications have been published within this topic receiving 286142 citations.
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TL;DR: In this article, a sonochemical reduction of an aqueous solution containing ammonium dichromate [(NH4)2Cr2O7] and potassium permanganate (KMnO4), respectively, was used to obtain nanosized ultrafine powders of manganese oxide and chromium oxide.
Abstract: Ultrafine powders of chromium oxide (Cr2O3) and manganese oxide (Mn2O3) have been prepared at room temperature by the sonochemical reduction of an aqueous solution containing ammonium dichromate [(NH4)2Cr2O7] and potassium permanganate (KMnO4), respectively. The yield of the sonochemical reduction has been enhanced by raising the reaction temperature or by using an aqueous solution of ethanol (0.1 M). The solid oxide residue formed on insonation has been characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), differential scanning calorimetry (DSC), elemental analysis, electron microscopy (TEM, SEM/EDX), powder density, particle size (adsorption and microscopy), and BET surface area measurements. The powders are nanosized (50−200 nm), and the surface area varies from 35 to 48 m2/g. The as-formed X-ray amorphous Mn2O3 and Cr2O3 powders were converted into crystalline form by heating them at 600 and 900 K, for 4 h, respectively.
86 citations
TL;DR: In this paper, micro-to-mesoporous MIL-100(Fe,Cr) and MIL-101(Cr) composites were synthesized using a mesoporous resorcinol-formaldehyde based xerogel as binding agent.
86 citations
TL;DR: Comparison of adsorption capacities of the postcrosslinked polymer, chloromethylated polymer and nonpolar porous polymer revealed that the adsorptive ability of MTBE from aqueous solution is dependent on both pore structure and surface chemistry of polymeric adsorbents, and the high adsor adaptation efficiency of thePostcross linked polymer towards MTBE is attributed to its high surface area, large micropore volume and moderate hydrophility.
86 citations
TL;DR: In this article, an alternative method using urea as organic matrix to prepare CoS2/γ-Al2O3 HDS catalysts based on drying (urea-matrix drying, UMxD) or combustion (UREa-metrix combustion, UMXC) processes have been developed and compared with the traditional wet methods (sequential, WSI, and co-impregnation, WCI) and chelating method (ChM) in order to determine their influence on the HDS catalyst performance.
Abstract: An alternative method using urea as organic matrix to prepare CoMoS2/γ-Al2O3 HDS catalysts based on drying (urea-matrix drying, UMxD) or combustion (urea-matrix combustion, UMxC) processes have been developed and compared with the traditional wet methods (sequential, WSI, and co-impregnation, WCI) and chelating method (ChM) in order to determine their influence on the HDS catalytic process. The catalytic performance of the alumina-supported CoMo catalysts was evaluated in a continuous flow reactor using the hydrodesulfurization of thiophene as a model reaction. The oxidic precursors and the sulfurized catalysts were characterized using elemental analysis, X-ray diffraction (XRD), laser Raman spectroscopy (LRS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), high resolution transmission electron microscopy (HRTEM), temperature-programmed reduction (TPR-H2) and BET surface area measurements. It has been found that the urea–organic matrix method facilitates well-dispersed Co- and Mo-oxo species (mono and polymolybdate) formation, whereas the conventional impregnation techniques lead to mixed-metal oxides formation. This was reflected in the sulfurized phase morphology and structural disorder degree of carbon material deposited on the catalyst surface upon the sulfurizing process using thiophene as sulfurizing agent. The preparation method notably affects the thiophene-HDS specific rates, showing the following activity order: UMxD>UMxC>WCI>WSI>ChM, while an opposite trend for relative rate of HYD to HDS reactions was observed. A carbon structural effect together with high stacking degree of the sulfurized phases seem to be mainly responsible for the high HDS activity of alumina-supported CoMo catalysts prepared by the urea–organic matrix method, which appears very promising for HDS catalysts development.
86 citations
TL;DR: In this article, the gas release properties and char structural evolution during pyrolysis of cotton stalks were investigated by means of FTIR and N2 physisorption techniques.
86 citations