TY  - CONF
AU  - Rac, Vladislav
AU  - Rakić, Vesna
AU  - Stošić, Dušan
AU  - Auroux, Aline
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10785
AB  - Given the great many applications of heterogeneous acid-base catalysis, the acidity and basicity of solid oxide catalysts (non-porous, such as ceria, zirconia or titania, or porous, such as zeolites) are considered crucial, among various characteristics which influence their performance. Namely, the concentration of acid/basic sites, their nature and their strengths are the most important parameters. Different methods are routinely being applied in the study of acidity/basicity, most often infrared spectroscopy and temperature programmed desorption. However, in terms of exact quantitative data on acidic/basic site strength distributions, a calorimetric method stands out as exceptional. It is designed to simultaneously record adsorption isotherms of basic (NH3) or acidic (SO2) probe molecules and the related thermal effects, via coupling of a calorimeter and a calibrated volumetric line equipped with pressure gauges. Microcalorimetric-volumetric measurements of adsorption yield several sets of results: the total number of sites (µmol/g), the concentration of irreversibly adsorbed probe molecules (number of “strong” sites, µmol/g), integral heats of adsorption (J/g) and differential heats of adsorption (kJ/mol), i.e. the distribution of strengths of the acid/basic sites. Examples of these unique results, which provide a fully quantitative image of acidity/basicity of oxide materials, unparalleled by any other technique, will be presented.
PB  - Belgrade : Serbian Ceramic Society
C3  - Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade
T1  - Quantifying acidity and basicity of oxides: a calorimetric approach
SP  - 38
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10785
ER  - 

@conference{
author = "Rac, Vladislav and Rakić, Vesna and Stošić, Dušan and Auroux, Aline",
year = "2022",
abstract = "Given the great many applications of heterogeneous acid-base catalysis, the acidity and basicity of solid oxide catalysts (non-porous, such as ceria, zirconia or titania, or porous, such as zeolites) are considered crucial, among various characteristics which influence their performance. Namely, the concentration of acid/basic sites, their nature and their strengths are the most important parameters. Different methods are routinely being applied in the study of acidity/basicity, most often infrared spectroscopy and temperature programmed desorption. However, in terms of exact quantitative data on acidic/basic site strength distributions, a calorimetric method stands out as exceptional. It is designed to simultaneously record adsorption isotherms of basic (NH3) or acidic (SO2) probe molecules and the related thermal effects, via coupling of a calorimeter and a calibrated volumetric line equipped with pressure gauges. Microcalorimetric-volumetric measurements of adsorption yield several sets of results: the total number of sites (µmol/g), the concentration of irreversibly adsorbed probe molecules (number of “strong” sites, µmol/g), integral heats of adsorption (J/g) and differential heats of adsorption (kJ/mol), i.e. the distribution of strengths of the acid/basic sites. Examples of these unique results, which provide a fully quantitative image of acidity/basicity of oxide materials, unparalleled by any other technique, will be presented.",
publisher = "Belgrade : Serbian Ceramic Society",
journal = "Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade",
title = "Quantifying acidity and basicity of oxides: a calorimetric approach",
pages = "38",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10785"
}

Rac, V., Rakić, V., Stošić, D.,& Auroux, A.. (2022). Quantifying acidity and basicity of oxides: a calorimetric approach. in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade
Belgrade : Serbian Ceramic Society., 38.
https://hdl.handle.net/21.15107/rcub_vinar_10785

Rac V, Rakić V, Stošić D, Auroux A. Quantifying acidity and basicity of oxides: a calorimetric approach. in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade. 2022;:38.
https://hdl.handle.net/21.15107/rcub_vinar_10785 .

Rac, Vladislav, Rakić, Vesna, Stošić, Dušan, Auroux, Aline, "Quantifying acidity and basicity of oxides: a calorimetric approach" in Advanced Ceramics and Application : 10th Serbian Ceramic Society Conference : program and the book of abstracts; September 26-27, 2022; Belgrade (2022):38,
https://hdl.handle.net/21.15107/rcub_vinar_10785 .

TY  - JOUR
AU  - Bosnar, Sanja
AU  - Rac, Vladislav
AU  - Stošić, Dušan
AU  - Travert, Arnaud
AU  - Postole, Georgeta
AU  - Auroux, Aline
AU  - Škapin, Srečo Davor
AU  - Damjanović-Vasilić, Ljiljana S.
AU  - Bronić, Josip
AU  - Du, Xuesen
AU  - Marković, Smilja
AU  - Pavlović, Vladimir B.
AU  - Rakić, Vesna M.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10017
AB  - Dual templating approach, using hexadecyltrimethylammonium bromide (CTAB), was employed in an attempt to synthesize hierarchical ZSM-5 zeolite. Amount of mesoporogen and the duration of aging of the precursor were varied. Majority of the synthesis routes resulted in phase separation, yielding separate ZSM-5 and amorphous mesoporous material. The relative amounts of the two phases were dependent on the CTAB amount ratio and also significantly on the duration of precursor aging before CTAB addition. One particular combination of the two factors led to the formation of a homogeneous hierarchical form of ZSM-5 with leafy morphology, consisting of intergrown thin crystalline sheets which formed flower-like structures. The hierarchical ZSM-5 possessed significant microporous (≈95 m2/g) and highly developed mesoporous surface (≈470 m2/g), with a relatively broad distribution of mesopore sizes (<20 nm). The acidity of all samples was studied in detail. Isothermal microcalorimetry/volumetry of ammonia adsorption provided quantitative data on the number and distribution of strength of acidic sites. In situ FTIR of pyridine and collidine adsorption was used to quantify Brønsted and Lewis acid sites, and to provide information on their location - in the micropores or mesopores/external surface. The hierarchical ZSM-5 possessed both Lewis and Brønsted acidity, with Brønsted sites located mainly in the micropores. All samples were fully characterized using XRD, low temperature nitrogen adsorption, FESEM and EDS. The synthetic route used for obtaining the ZSM-5 zeolite with flower-like morphology is a simple strategy for preparing hierarchical ZSM-5 forms targeting enhanced diffusivity and accessibility of catalytically active sites.
T2  - Microporous and Mesoporous Materials
T1  - Overcoming phase separation in dual templating: A homogeneous hierarchical ZSM-5 zeolite with flower-like morphology, synthesis and in-depth acidity study
VL  - 329
SP  - 111534
DO  - 10.1016/j.micromeso.2021.111534
ER  - 

@article{
author = "Bosnar, Sanja and Rac, Vladislav and Stošić, Dušan and Travert, Arnaud and Postole, Georgeta and Auroux, Aline and Škapin, Srečo Davor and Damjanović-Vasilić, Ljiljana S. and Bronić, Josip and Du, Xuesen and Marković, Smilja and Pavlović, Vladimir B. and Rakić, Vesna M.",
year = "2021",
abstract = "Dual templating approach, using hexadecyltrimethylammonium bromide (CTAB), was employed in an attempt to synthesize hierarchical ZSM-5 zeolite. Amount of mesoporogen and the duration of aging of the precursor were varied. Majority of the synthesis routes resulted in phase separation, yielding separate ZSM-5 and amorphous mesoporous material. The relative amounts of the two phases were dependent on the CTAB amount ratio and also significantly on the duration of precursor aging before CTAB addition. One particular combination of the two factors led to the formation of a homogeneous hierarchical form of ZSM-5 with leafy morphology, consisting of intergrown thin crystalline sheets which formed flower-like structures. The hierarchical ZSM-5 possessed significant microporous (≈95 m2/g) and highly developed mesoporous surface (≈470 m2/g), with a relatively broad distribution of mesopore sizes (<20 nm). The acidity of all samples was studied in detail. Isothermal microcalorimetry/volumetry of ammonia adsorption provided quantitative data on the number and distribution of strength of acidic sites. In situ FTIR of pyridine and collidine adsorption was used to quantify Brønsted and Lewis acid sites, and to provide information on their location - in the micropores or mesopores/external surface. The hierarchical ZSM-5 possessed both Lewis and Brønsted acidity, with Brønsted sites located mainly in the micropores. All samples were fully characterized using XRD, low temperature nitrogen adsorption, FESEM and EDS. The synthetic route used for obtaining the ZSM-5 zeolite with flower-like morphology is a simple strategy for preparing hierarchical ZSM-5 forms targeting enhanced diffusivity and accessibility of catalytically active sites.",
journal = "Microporous and Mesoporous Materials",
title = "Overcoming phase separation in dual templating: A homogeneous hierarchical ZSM-5 zeolite with flower-like morphology, synthesis and in-depth acidity study",
volume = "329",
pages = "111534",
doi = "10.1016/j.micromeso.2021.111534"
}

Bosnar, S., Rac, V., Stošić, D., Travert, A., Postole, G., Auroux, A., Škapin, S. D., Damjanović-Vasilić, L. S., Bronić, J., Du, X., Marković, S., Pavlović, V. B.,& Rakić, V. M.. (2021). Overcoming phase separation in dual templating: A homogeneous hierarchical ZSM-5 zeolite with flower-like morphology, synthesis and in-depth acidity study. in Microporous and Mesoporous Materials, 329, 111534.
https://doi.org/10.1016/j.micromeso.2021.111534

Bosnar S, Rac V, Stošić D, Travert A, Postole G, Auroux A, Škapin SD, Damjanović-Vasilić LS, Bronić J, Du X, Marković S, Pavlović VB, Rakić VM. Overcoming phase separation in dual templating: A homogeneous hierarchical ZSM-5 zeolite with flower-like morphology, synthesis and in-depth acidity study. in Microporous and Mesoporous Materials. 2021;329:111534.
doi:10.1016/j.micromeso.2021.111534 .

Bosnar, Sanja, Rac, Vladislav, Stošić, Dušan, Travert, Arnaud, Postole, Georgeta, Auroux, Aline, Škapin, Srečo Davor, Damjanović-Vasilić, Ljiljana S., Bronić, Josip, Du, Xuesen, Marković, Smilja, Pavlović, Vladimir B., Rakić, Vesna M., "Overcoming phase separation in dual templating: A homogeneous hierarchical ZSM-5 zeolite with flower-like morphology, synthesis and in-depth acidity study" in Microporous and Mesoporous Materials, 329 (2021):111534,
https://doi.org/10.1016/j.micromeso.2021.111534 . .