In this contribution, we investigated the preparation of Ni/SiO 2 catalysts with aqueous [Ni(OH 2 ) 6 ](NO 3 ) 2 solutions via the impregnation and drying method using ordered mesoporous silica SBA-15 (mesopore diameter of 9 nm) as model support to study each step in the preparation: impregnation, drying, calcination, and reduction. After impregnation, not all the mesopores of SBA-15 appeared filled with precursor solution. Consecutive drying led to formation of 9 nm Ni 3 (NO 3 ) 2 (OH) 4 crystallites exclusively within the mesopores. During air calcination, severe sintering and redistribution took place, resulting in a low NiO dispersion, including large NiO crystals outside of the mesopores and rodlike NiO particles inside the mesopores. The degree of sintering depended on the concentration of Ni 3 (NO 3 ) 2 (OH) 4 decomposition products (NO 2 , N 2 O, O 2 and H 2 O), and in particular NO 2 and O 2 were found to promote sintering and redistribution. Therefore, maintaining low concentrations of the latter components during the thermal nitrate decomposition is advocated, which was achieved by carrying out the treatment in the presence of H 2 . The latter treatment prevented formation of NO 2 /O 2 as decomposition products, moderated the decomposition rate of Ni 3 (NO 3 ) 2 (OH) 4 into NiO as observed from in situ XRD experiments, and led to NiO particles of 3 nm on average at a loading of 20 wt % Ni/SiO 2 .
An explanation is put forward for the beneficial effect of thermal decomposition of supported Ni 3 (NO 3 ) 2 (OH) 4 in NO/He flow (0.1-1 vol%) that enables preparation of well-dispersed (3-5 nm particles) 24 wt% Ni-catalysts via impregnation and drying using aqueous [Ni(OH 2 ) 6 ](NO 3 ) 2 precursor solution. Moreover, combining electron tomography, XRD and N 2 -physisorption with SBA-15 support yielded a clear picture of the impact of air, He and NO/He gas atmospheres on NiO shape and distribution. TGA/MS indicated that NO 2 , N 2 O, H 2 O products evolved more gradually in NO/He. In situ XRD and DSC revealed that NO lowers the nitrate decomposition rate and appears less endothermic than in air supposedly due to exothermic scavenging of oxygen by NO, which is supported by MS results. The Ni/SiO 2 catalyst prepared via the NO-method displayed a higher activity in the hydrogenation of soybean oil as the required hydrogenation time decreased by 30% compared to the traditionally air calcined catalyst.
Butene skeletal isomerization over H-ferrierite (H-FER) is monitored in a catalysis setup including a tapered element oscillating microbalance (TEOM) and using in situ infrared (IR) spectroscopy. For the first time the location and number of vacant Brønsted acid groups sited in the 10, 8, 6, and 5 membered rings (MRs) of the H-ferrierite framework are established as a function of time-on-stream (TOS). By deconvolution of the acid site-band, it is determined that with proceeding reaction the 8 MR channels are blocked and the available micropore volume and Brønsted acidity on the aged H-ferrierite will be primarily located inside the 10 MR channels. When a maximum amount of hydrocarbons is deposited on the catalyst, vacant Brønsted acid sites are still present. Additionally, IR spectroscopy shows that with TOS carbonaceous deposits are slowly converted from hydrogen-rich alkyl-aromatics into hydrogen-poor cyclopenta-fused-alkyl-aromatics, reducing by-product formation and therefore enhancing isobutene selectivity.
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