TY  - JOUR
AU  - Stojanović, Srna R.
AU  - Vranješ, Mila
AU  - Šaponjić, Zoran
AU  - Rac, Vladislav
AU  - Rakić, Vesna M.
AU  - Ignjatović, Ljubiša M.
AU  - Damjanović-Vasilić, Ljiljana S.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10343
AB  - Removal of the β-blocker atenolol from an aqueous solution was studied using TiO2/zeolites, prepared by a simple and cost-effective solid-state dispersion method. Synthetic zeolites 13X and ZSM-5 (Si/Al = 40) and natural zeolite clinoptilolite were used as one component of the hybrid materials, whereas TiO2 nanocrystals obtained from TiO2 nanotubes and P25 TiO2 nanoparticles were used as the other. The synthesized materials were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transformed infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy and scanning electron microscopy with energy-dispersive spectroscopy. The photocatalytic activity for the degradation of atenolol was investigated under simulated solar light. Additionally, the effect of initial pH on atenolol removal and the reusability of prepared catalysts were tested. The best loading of TiO2 was 20 wt% over all investigated zeolites. The degradation of atenolol followed the pseudo-first-order kinetics. The photocatalytic degradation of atenolol after 70 min of irradiation was ~ 50% for TiO2/13X materials, ~ 45% for clinoptilolite combined with P25 TiO2 and ~ 57% for clinoptilolite combined with TiO2 nanocrystals obtained from TiO2 nanotubes. The results showed the highest removal efficiency after 70 min of irradiation for ZSM-5 combined with P25 TiO2 (~ 94%), followed by ZSM-5 combined with TiO2 nanocrystals obtained from TiO2 nanotubes (~ 88%) at near-neutral pH (~ 6.5). The total removal of atenolol from an aqueous solution for TiO2/ZSM-5 materials resulted from two processes: adsorption and photocatalytic degradation. The TiO2/ZSM-5 photocatalysts can be easily recovered and reused as their activity was preserved after four cycles.
T2  - International Journal of Environmental Science and Technology
T1  - Photocatalytic performance of TiO2/zeolites under simulated solar light for removal of atenolol from aqueous solution
DO  - 10.1007/s13762-022-04305-6
ER  - 

@article{
author = "Stojanović, Srna R. and Vranješ, Mila and Šaponjić, Zoran and Rac, Vladislav and Rakić, Vesna M. and Ignjatović, Ljubiša M. and Damjanović-Vasilić, Ljiljana S.",
year = "2022",
abstract = "Removal of the β-blocker atenolol from an aqueous solution was studied using TiO2/zeolites, prepared by a simple and cost-effective solid-state dispersion method. Synthetic zeolites 13X and ZSM-5 (Si/Al = 40) and natural zeolite clinoptilolite were used as one component of the hybrid materials, whereas TiO2 nanocrystals obtained from TiO2 nanotubes and P25 TiO2 nanoparticles were used as the other. The synthesized materials were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transformed infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy and scanning electron microscopy with energy-dispersive spectroscopy. The photocatalytic activity for the degradation of atenolol was investigated under simulated solar light. Additionally, the effect of initial pH on atenolol removal and the reusability of prepared catalysts were tested. The best loading of TiO2 was 20 wt% over all investigated zeolites. The degradation of atenolol followed the pseudo-first-order kinetics. The photocatalytic degradation of atenolol after 70 min of irradiation was ~ 50% for TiO2/13X materials, ~ 45% for clinoptilolite combined with P25 TiO2 and ~ 57% for clinoptilolite combined with TiO2 nanocrystals obtained from TiO2 nanotubes. The results showed the highest removal efficiency after 70 min of irradiation for ZSM-5 combined with P25 TiO2 (~ 94%), followed by ZSM-5 combined with TiO2 nanocrystals obtained from TiO2 nanotubes (~ 88%) at near-neutral pH (~ 6.5). The total removal of atenolol from an aqueous solution for TiO2/ZSM-5 materials resulted from two processes: adsorption and photocatalytic degradation. The TiO2/ZSM-5 photocatalysts can be easily recovered and reused as their activity was preserved after four cycles.",
journal = "International Journal of Environmental Science and Technology",
title = "Photocatalytic performance of TiO2/zeolites under simulated solar light for removal of atenolol from aqueous solution",
doi = "10.1007/s13762-022-04305-6"
}

Stojanović, S. R., Vranješ, M., Šaponjić, Z., Rac, V., Rakić, V. M., Ignjatović, L. M.,& Damjanović-Vasilić, L. S.. (2022). Photocatalytic performance of TiO2/zeolites under simulated solar light for removal of atenolol from aqueous solution. in International Journal of Environmental Science and Technology.
https://doi.org/10.1007/s13762-022-04305-6

Stojanović SR, Vranješ M, Šaponjić Z, Rac V, Rakić VM, Ignjatović LM, Damjanović-Vasilić LS. Photocatalytic performance of TiO2/zeolites under simulated solar light for removal of atenolol from aqueous solution. in International Journal of Environmental Science and Technology. 2022;.
doi:10.1007/s13762-022-04305-6 .

Stojanović, Srna R., Vranješ, Mila, Šaponjić, Zoran, Rac, Vladislav, Rakić, Vesna M., Ignjatović, Ljubiša M., Damjanović-Vasilić, Ljiljana S., "Photocatalytic performance of TiO2/zeolites under simulated solar light for removal of atenolol from aqueous solution" in International Journal of Environmental Science and Technology (2022),
https://doi.org/10.1007/s13762-022-04305-6 . .

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 . .

TY  - JOUR
AU  - Rajić, Vladimir
AU  - Simatović Stojković, Ivana
AU  - Veselinović, Ljiljana M.
AU  - Belošević-Čavor, Jelena
AU  - Novaković, Mirjana M.
AU  - Popović, Maja
AU  - Škapin, Srečo Davor
AU  - Mojović, Miloš
AU  - Stojadinović, Stevan
AU  - Rac, Vladislav
AU  - Častvan Janković, Ivona
AU  - Marković, Smilja
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9679
AB  - Eco-friendly and rapid microwave processing of a precipitate was used to produce Fe-doped zinc oxide (Zn1−xFexO, x = 0, 0.05, 0.1, 0.15 and 0.20; ZnO:Fe) nanoparticles, which were tested as catalysts toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in a moderately alkaline solution. The phase composition, crystal structure, morphology, textural properties, surface chemistry, optical properties and band structure were examined to comprehend the influence of Zn2+ partial substitution with Fe3+ on the catalytic activity of ZnO:Fe. Linear sweep voltammetry showed an improved catalytic activity of ZnO:5Fe toward the ORR, compared to pure ZnO, while with increased amounts of the Fe-dopant the activity decreased. The improvement was suggested by a more positive onset potential (0.394 V vs. RHE), current density (0.231 mA cm−2 at 0.150 V vs. RHE), and faster kinetics (Tafel slope, b = 248 mV dec−1), and it may be due to the synergistic effect of (1) a sufficient amount of surface oxygen vacancies, and (2) a certain amount of plate-like particles composed of crystallites with well developed (0001) and (000) facets. Quite the contrary, the OER study showed that the introduction of Fe3+ ions into the ZnO crystal structure resulted in enhanced catalytic activity of all ZnO:Fe samples, compared to pure ZnO, probably due to the modified binding energy and an optimized band structure. With the maximal current density of 1.066 mA cm−2 at 2.216 V vs. RHE, an onset potential of 1.856 V vs. RHE, and the smallest potential difference between the OER and ORR (ΔE = 1.58 V), ZnO:10Fe may be considered a promising bifunctional catalyst toward the OER/ORR in moderately alkaline solution. This study demonstrates that the electrocatalytic activity of ZnO:Fe strongly depends on the defect chemistry and consequently the band structure. Along with providing fundamental insight into the electrocatalytic activity of ZnO:Fe, the study also indicates an optimal stoichiometry for enhanced bifunctional activity toward the OER/ORR, compared to pure ZnO.
T2  - Physical Chemistry Chemical Physics
T1  - Bifunctional catalytic activity of Zn1−xFexO toward the OER/ORR: seeking an optimal stoichiometry
VL  - 22
IS  - 38
SP  - 22078
EP  - 22095
DO  - 10.1039/D0CP03377D
ER  - 

@article{
author = "Rajić, Vladimir and Simatović Stojković, Ivana and Veselinović, Ljiljana M. and Belošević-Čavor, Jelena and Novaković, Mirjana M. and Popović, Maja and Škapin, Srečo Davor and Mojović, Miloš and Stojadinović, Stevan and Rac, Vladislav and Častvan Janković, Ivona and Marković, Smilja",
year = "2020",
abstract = "Eco-friendly and rapid microwave processing of a precipitate was used to produce Fe-doped zinc oxide (Zn1−xFexO, x = 0, 0.05, 0.1, 0.15 and 0.20; ZnO:Fe) nanoparticles, which were tested as catalysts toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in a moderately alkaline solution. The phase composition, crystal structure, morphology, textural properties, surface chemistry, optical properties and band structure were examined to comprehend the influence of Zn2+ partial substitution with Fe3+ on the catalytic activity of ZnO:Fe. Linear sweep voltammetry showed an improved catalytic activity of ZnO:5Fe toward the ORR, compared to pure ZnO, while with increased amounts of the Fe-dopant the activity decreased. The improvement was suggested by a more positive onset potential (0.394 V vs. RHE), current density (0.231 mA cm−2 at 0.150 V vs. RHE), and faster kinetics (Tafel slope, b = 248 mV dec−1), and it may be due to the synergistic effect of (1) a sufficient amount of surface oxygen vacancies, and (2) a certain amount of plate-like particles composed of crystallites with well developed (0001) and (000) facets. Quite the contrary, the OER study showed that the introduction of Fe3+ ions into the ZnO crystal structure resulted in enhanced catalytic activity of all ZnO:Fe samples, compared to pure ZnO, probably due to the modified binding energy and an optimized band structure. With the maximal current density of 1.066 mA cm−2 at 2.216 V vs. RHE, an onset potential of 1.856 V vs. RHE, and the smallest potential difference between the OER and ORR (ΔE = 1.58 V), ZnO:10Fe may be considered a promising bifunctional catalyst toward the OER/ORR in moderately alkaline solution. This study demonstrates that the electrocatalytic activity of ZnO:Fe strongly depends on the defect chemistry and consequently the band structure. Along with providing fundamental insight into the electrocatalytic activity of ZnO:Fe, the study also indicates an optimal stoichiometry for enhanced bifunctional activity toward the OER/ORR, compared to pure ZnO.",
journal = "Physical Chemistry Chemical Physics",
title = "Bifunctional catalytic activity of Zn1−xFexO toward the OER/ORR: seeking an optimal stoichiometry",
volume = "22",
number = "38",
pages = "22078-22095",
doi = "10.1039/D0CP03377D"
}

Rajić, V., Simatović Stojković, I., Veselinović, L. M., Belošević-Čavor, J., Novaković, M. M., Popović, M., Škapin, S. D., Mojović, M., Stojadinović, S., Rac, V., Častvan Janković, I.,& Marković, S.. (2020). Bifunctional catalytic activity of Zn1−xFexO toward the OER/ORR: seeking an optimal stoichiometry. in Physical Chemistry Chemical Physics, 22(38), 22078-22095.
https://doi.org/10.1039/D0CP03377D

Rajić V, Simatović Stojković I, Veselinović LM, Belošević-Čavor J, Novaković MM, Popović M, Škapin SD, Mojović M, Stojadinović S, Rac V, Častvan Janković I, Marković S. Bifunctional catalytic activity of Zn1−xFexO toward the OER/ORR: seeking an optimal stoichiometry. in Physical Chemistry Chemical Physics. 2020;22(38):22078-22095.
doi:10.1039/D0CP03377D .

Rajić, Vladimir, Simatović Stojković, Ivana, Veselinović, Ljiljana M., Belošević-Čavor, Jelena, Novaković, Mirjana M., Popović, Maja, Škapin, Srečo Davor, Mojović, Miloš, Stojadinović, Stevan, Rac, Vladislav, Častvan Janković, Ivona, Marković, Smilja, "Bifunctional catalytic activity of Zn1−xFexO toward the OER/ORR: seeking an optimal stoichiometry" in Physical Chemistry Chemical Physics, 22, no. 38 (2020):22078-22095,
https://doi.org/10.1039/D0CP03377D . .