Acidic and neutral caesium salts of 12-molybdophosphoric acid supported on SBA-15 mesoporous silica. The influence of Cs concentration and surface coverage on textural and structural properties

Popa, Alexandru; Sasca, Viorel; Verdeş, Orsina; Barvinschi, Paul; Holclajtner-Antunović, Ivanka

doi:10.1016/j.materresbull.2013.11.015

Cited by 19 publications

(10 citation statements)

References 45 publications

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“…The final process evidenced by an exothermic peak over 773 K is assigned to the destruction of Keggin structure and crystallization of constitutive oxides. For all loadings of CsPM-SBA-15 composites an exothermic peak could be observed on DTA curve at a temperature higher than 873 K. This exothermic peak could be assigned to the decomposition of active phase CsPM and crystallization of constitutive oxides resulted after decomposition [29].…”

Section: Thermal Analysismentioning

confidence: 86%

“…The lower reaction rate over 40 Cs 1 PM-SBA-15 could be explained as a result of more difficult access to acid sites, as some aggregation of active phase at the surface of the support could be expected. However, this aggregation would remain limited for low loadings of the supported samples, but for 40 wt% loading, some small peaks of crystalline Cs 1 PM phase was found by XRD measurements [29].…”

Section: Catalytic Testsmentioning

confidence: 99%

“…Therefore, the complete elimination of this water was studied. TG-DTA measurements of both Cs 1 PM and Cs 3 PM were studied in detail in our previous paper [29]. For easier tracking of subsequent experiments, some considerations from the previous paper are given below.…”

Section: Thermal Analysismentioning

confidence: 99%

“…The NH 3 -TPD experiments were recorded as the TG-DTG and DTA curves (not shown). The results of TPD experiments for determination of amount and strengths of acidic sites in the temperature range of 373-873 K were presented in our previous paper [29] and in another paper sent for publication (unpublished data). The desorption peak ascribed to the removal of constitutional water resulted from acidic protons of acidic Cs salt is observed at 713 K. For Cs 1 PM-SBA15 composites the removal of constitutional water take place at temperature higher than 773 K. For pure Cs 1 PM and Cs 1 PM-SBA15 composites, the number of protons from constitutional water content were determined as shown in Table 2.…”

Section: The Tpd Of Ethanolmentioning

confidence: 99%

“…In this study, the preparation of the Cs salts of molybdophosphoric acid Cs 1 H 2 PMo 12 O 40 (Cs 1 PM), and Cs 3 PMo 12 O 40 (Cs 3 PM), by supporting on SBA-15 molecular sieve, in the concentration of 20, 30 and 40 wt% was carried out. In our previous paper [29], a textural and structural characterization of these compounds are given in details. In this work, we have investigated the dehydration of ethanol on available surface acidic sites of HPAs and also the influence of Cs concentration and surface coverage of the obtained composites in reference to the bulk solid HPAs for the catalytic reaction.…”

Section: Introductionmentioning

confidence: 99%

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Adsorption–desorption and catalytic properties of SBA-15 supported cesium salts of 12-molybdophosphoric acid for the dehydration of ethanol

Popa

Sasca

Verdeş

et al. 2015

Reac Kinet Mech Cat

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Cesium salts of molybdophosphoric acid with varying amounts of the cations Cs 1 H 2 PMo 12 O 40 and Cs 3 PMo 12 O 40 have been prepared as pure or supported on SBA-15. The adsorption of ethanol and its temperature programmed desorption-TPD using thermogravimetry were studied for SBA-15 supported and unsupported Cs salts. The evolved gases during the adsorption-desorption of ethanol on CsHPM/ SBA-15 composites were identified by online mass spectrometry coupled with thermogravimetry. The main products observed in the evolved gases during the desorption of ethanol were C 2 H 4 , C 3 H 6 and unreacted ethanol. The amount of acidic sites of the composites was estimated by ammonia adsorption-desorption. The dehydration of ethanol was used to test the catalytic properties of the CsHPM samples incorporated on the silica matrix. SBA15-supported catalysts, appeared to be more active than bulk catalysts in vapor phase dehydration and dehydrogenation of ethanol reactions. The effect of the support leads to higher values of dehydration rates of ethanol as well as higher values of ethylene and acetaldehyde formation rates.

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Section: Thermal Analysismentioning

confidence: 86%

Section: Catalytic Testsmentioning

confidence: 99%

Section: Thermal Analysismentioning

confidence: 99%

Section: The Tpd Of Ethanolmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Adsorption–desorption and catalytic properties of SBA-15 supported cesium salts of 12-molybdophosphoric acid for the dehydration of ethanol

Popa

Sasca

Verdeş

et al. 2015

Reac Kinet Mech Cat

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Optimization and comparative analysis of Cs ion intercalated H3PMO12O40 photocathode: one-step hydrothermal strategy

Nadaf

Patil

Kalantre³

et al. 2021

J Mater Sci: Mater Electron

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Acidic nickel salts of Keggin type heteropolyacids supported on SBA-15 mesoporous silica

et al. 2015

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A series of heteropolyacids-mesoporous silica composites were prepared from nickel salt of molybdophosphoric acid Ni 1 HPMo 12 O 40 (NiHPM) by supporting on SBA-15 mesoporous silica in different concentrations of active phase. The structure and texture of these NiHPM/ SBA-15 composites were studied by XRD, FT-IR and micro-Raman spectroscopy, nitrogen physisorption at 77 K, UV-Vis-DRS and SEM-EDX. The effect of the support on thermal stability was investigated by TG-DTG, DTA and DSC methods. By impregnation of Ni salt on mesoporous silica the thermal stability of the Keggin structure increases in comparison with its parent bulk heteropolyacid. From XRD at small angles could be observed that NiHPM/SBA-15 composites with low surface coverage preserve the mesopore structure of silica, with well dispersed NiHPM on the surface of the pore walls for SBA-15. The adsorption of ammonia and its temperature programmed desorption using thermogravimetry were studied for acidity evaluation. The total acidity of the weak and strong acidic sites of NiHPM/SBA-15 composites is obviously increases in comparison with bulk Ni salt. The main products observed in the evolved gases during desorption of NH 3 were NH 3 , CO 2 and NO/ NO 2 .

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Acidic and neutral caesium salts of 12-molybdophosphoric acid supported on SBA-15 mesoporous silica. The influence of Cs concentration and surface coverage on textural and structural properties

Cited by 19 publications

References 45 publications

Adsorption–desorption and catalytic properties of SBA-15 supported cesium salts of 12-molybdophosphoric acid for the dehydration of ethanol

Adsorption–desorption and catalytic properties of SBA-15 supported cesium salts of 12-molybdophosphoric acid for the dehydration of ethanol

Optimization and comparative analysis of Cs ion intercalated H3PMO12O40 photocathode: one-step hydrothermal strategy

Acidic nickel salts of Keggin type heteropolyacids supported on SBA-15 mesoporous silica

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