Modification of silica with NH4+ agents to prepare an acidic support for iridium hydrogenation catalyst

Janiszewska, Ewa; Kot, Monika; Zieliński, Michał

doi:10.1016/j.micromeso.2017.07.031

Cited by 19 publications

(15 citation statements)

References 32 publications

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“…The higher acidity of the SiO-F-0.1 surface favors a slightly better dispersion of the iridium active phase. The obtained results are in good agreements with data reported for modified amorphous silica in our previous work [ 8 ].…”

Section: Resultssupporting

confidence: 92%

“…It has been shown that amorphous silica modified with aqueous solution of ammonium chloride or ammonium nitrate in presence of ammonia solution generates weak acidic properties of the material. The results presented in the literature confirmed that the presence of acid sites is essential for toluene hydrogenation [ 8 ]. The modification of silica materials using ammonium agents may be a simple, cheap, and effective route to obtain catalysts with enhanced activity for hydrogenation reactions.…”

Section: Introductionsupporting

confidence: 55%

“…The use of modified silica as iridium supports allowed to obtain a new class of catalysts characterized by high activities in the hydrogenation of toluene, greater than that of the iridium system supported on unmodified SiO 2 . A comparison of the activity obtained for the best Ir-SiO-F-0.1 catalyst with the results reported in the literature for iridium supported on modified acidic silica [ 8 ], alumina [ 26 ], as well as SBA-3 or SBA-15 [ 39 ], shows that the iridium catalyst supported on modified silica is more promising catalyst.…”

Section: Discussionmentioning

confidence: 85%

“…It has been demonstrated that the support used to disperse an active phase can affect catalyst activity for aromatic hydrocarbons hydrogenation. Several authors have evidenced that the performance of metal catalysts supported on acidic supports for hydrogenation of different organic compounds—e.g., benzene, toluene, and xylene—is enhanced in comparison to catalysts on inert supports, e.g., SiO 2 [ 4 , 5 , 6 , 7 , 8 ] and ordered mesoporous silica [ 9 , 10 , 11 ]. It was found that aromatics adsorbed on acid site can be hydrogenated with the activated hydrogen spillover from metal centers [ 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Modification of Amorphous Silica with Ammonium Agents on the Physicochemical Properties and Hydrogenation Activity of Ir/SiO2 Catalysts

Kot

Wojcieszak²,

Janiszewska

et al. 2021

Materials

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The modification of commercial silica with solutions of NH4F or NH4Cl salts, followed by thermal treatment, enabled generation of the acidic sites in SiO2 and changed its textural properties. The use of ammonium salts solution also caused the generation of additional porosity. Using NH4F solution caused significant decrease in the specific surface area and the increase in the average pore diameter. The number and strength of resulting acid sites depend on the nature of anion in the applied ammonium salt and the concentration of salt solution. It has been found that the sample treated with NH4F presented higher total acidity (TPD–NH3) and the amount as well as the strength of acid sites increased with the concentration of the used modifier. As modified amorphous SiO2 materials used as a support for iridium (1 wt %, Ir(acac)3) nanoparticles permitted to obtain highly active catalysts for toluene hydrogenation under atmospheric pressure. The highest activity (expressed as the apparent rate and TOF) was obtained for iridium catalysts supported on silica modified by NH4F with the highest acidity. The modification of silica with NH4F favors the generation of centers able to adsorb toluene, which results in higher activity of this catalyst.

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Section: Resultssupporting

confidence: 92%

Section: Introductionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Modification of Amorphous Silica with Ammonium Agents on the Physicochemical Properties and Hydrogenation Activity of Ir/SiO2 Catalysts

Kot

Wojcieszak²,

Janiszewska

et al. 2021

Materials

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“…CoH/HBEA was less selective to the C 5+ hydrocarbons followed by Co/HBEA, Co/NaBEA and CoH/NaBEA, respectively with 48.7, 63.9, 66 and 71.9 %. The C 2 –C 4 olefins to paraffins ratio (Table ) show slight differences between the samples ,…”

Section: Resultsmentioning

confidence: 95%

Influence of Impregnation and Ion Exchange Sequence on Metal Localization, Acidity and Catalytic Performance of Cobalt BEA Zeolite Catalysts in Fischer‐Tropsch Synthesis

et al. 2018

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Cobalt distribution between the external surface and micropores and acidity of the large pore BEA zeolite were controlled by choosing the sequence of impregnation and ion exchange procedures. Higher concentration of ion exchangeable cobalt was observed in the catalyst prepared by ion‐exchange of the zeolite proton form. The presence of Na+ instead of H+ ions in the exchange positions of zeolite favored deposition of cobalt on the external surface. The acid sites in the zeolite micropores can be then restored by subsequent ion exchange of sodium with ammonium nitrate and calcination. The catalytic performance of the cobalt zeolite catalysts prepared using different impregnation and ion exchange procedures was tested in the Fischer‐Tropsch synthesis. Higher reaction rates were observed over the catalysts, which did not contain cobalt ions in the cation sites of the zeolite. Lower methane selectivity, higher selectivity to long chain hydrocarbons and high fraction of isomerized products are observed when cobalt species are located on the zeolite outer surface and acid sites inside the BEA zeolite micropores.

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Supported Nickel‐based Catalysts for Heterogeneous Hydrogenation of Aromatics

Wang,

Zhang,

Zhang

et al. 2023

ChemistrySelect

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Aromatic hydrocarbons are carcinogenic and can induce mutations in living organisms, posing a threat to the ecological environment and human life and health. Catalytic hydrogenation of aromatics to reduce the saturation of aromatics not only reduces their toxicity, but also greatly increases their potential value. Compared with the unsupported catalysts with only active components, the supported metal catalysts have higher catalytic activity and better selectivity, the catalytic activity of the hydrogenation reaction depends on the metal active phase and catalyst support. On metal/acid catalysts, the metal active center and nearby acid sites are involved in the conversion of aromatics, the active hydrogen leaking from the metal center can hydrogenate the adsorbed aromatics at the acid site. This paper reviews the recent research progress of nickel‐based catalysts for aromatic hydrocarbon catalytic hydrogenation and discusses the development prospects and challenges faced by non‐precious metal catalysts. In addition, the sulfur tolerance and hydrogen storage properties of catalysts for aromatics are reviewed.

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Modification of silica with NH4+ agents to prepare an acidic support for iridium hydrogenation catalyst

Cited by 19 publications

References 32 publications

Effect of Modification of Amorphous Silica with Ammonium Agents on the Physicochemical Properties and Hydrogenation Activity of Ir/SiO2 Catalysts

Effect of Modification of Amorphous Silica with Ammonium Agents on the Physicochemical Properties and Hydrogenation Activity of Ir/SiO2 Catalysts

Influence of Impregnation and Ion Exchange Sequence on Metal Localization, Acidity and Catalytic Performance of Cobalt BEA Zeolite Catalysts in Fischer‐Tropsch Synthesis

Supported Nickel‐based Catalysts for Heterogeneous Hydrogenation of Aromatics

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