TY  - JOUR
AU  - Kovač, Tijana
AU  - Džunuzović, Enis S.
AU  - Džunuzović, Jasna
AU  - Milićević, Bojana
AU  - Sredojević, Dušan
AU  - Brothers, Edward N
AU  - Nedeljković, Jovan M.
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2422
AB  - Surface modification of titanium dioxide nanoparticles (TiO2 NPs) with the biologically active molecule pyridoxine hydrochloride (vitamin B-6) was found to alter the optical properties. Microstructural characterization involving transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis revealed that the anatase TiO2 NPs had a narrow size distribution with an average diameter of 45 angstrom. The absorption onset of the surface-modified TiO2 samples was red-shifted by about 0.4 eV compared to the unmodified particles. The mode of binding between vitamin B-6 and the surface Ti atoms was investigated by Fourier transform infrared spectroscopy (FTIR). From the Benesi-Hildebrand plot, the stability constant of the surface complex was found to be of the order 10(2) M-1. The experimental findings were supported by detailed quantum chemical calculations based on the density functional theory (DFT). Agreement was found between the experimentally measured absorption spectra of the TiO2 NPs surface-modified with vitamin B-6 and the theoretically calculated electronic excitation spectra of the corresponding model system.
AB  - Површинска модификација наночестица титан-диоксида (ТiО2) биолошки активним молекулима пиридоксин-хидрохлорида (витамин B6) доводи до промене њихових оптичких својства. Микроструктурна карактеризација синтетисаних наночестица ТiО2 која обухвата трансмисиону електронску микроскопију (ТЕМ) и дифракцију рендгенских зрака (XRD) показала је да наночестице анатаза имају уску дистрибуцију величина са средњим пречником од 45 Å. Праг апсорпције површински модификованих наночестица ТiО2 је за 0,4 еV померен ка већим таласним дужинама у односу на спектар немодификованих честица. Коришћењем FTIR спектроскопије утврђен је начин везивања
витамина B6 за површинске атоме титана. Константа стабилности површинског комплекса је одређена на основу Бенеси–Хилдебрандове (Benesi–Hildebrand) анализе и износи 3,0×102 М-1. Експериментални резултати су поткрепљени детаљним квантно-хемијским прорачунима заснованим на теорији функционала густине (DFT). Утврђен је висок ниво сагласности између апсорпционог спектра наночестица ТiО2 и теоријски добијеног електронског ексцитационог спектра одговарајућег модела.
PB  - Belgrade : Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study
T1  - Апсорпција наночестица TiO2 површински модификованих витамином B6 у видљивом делу спектра: упоредна експериментална и DFT студија
VL  - 83
IS  - 7-8
SP  - 899
EP  - 909
DO  - 10.2298/JSC180131044K
ER  - 

@article{
author = "Kovač, Tijana and Džunuzović, Enis S. and Džunuzović, Jasna and Milićević, Bojana and Sredojević, Dušan and Brothers, Edward N and Nedeljković, Jovan M.",
year = "2018",
abstract = "Surface modification of titanium dioxide nanoparticles (TiO2 NPs) with the biologically active molecule pyridoxine hydrochloride (vitamin B-6) was found to alter the optical properties. Microstructural characterization involving transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis revealed that the anatase TiO2 NPs had a narrow size distribution with an average diameter of 45 angstrom. The absorption onset of the surface-modified TiO2 samples was red-shifted by about 0.4 eV compared to the unmodified particles. The mode of binding between vitamin B-6 and the surface Ti atoms was investigated by Fourier transform infrared spectroscopy (FTIR). From the Benesi-Hildebrand plot, the stability constant of the surface complex was found to be of the order 10(2) M-1. The experimental findings were supported by detailed quantum chemical calculations based on the density functional theory (DFT). Agreement was found between the experimentally measured absorption spectra of the TiO2 NPs surface-modified with vitamin B-6 and the theoretically calculated electronic excitation spectra of the corresponding model system., Површинска модификација наночестица титан-диоксида (ТiО2) биолошки активним молекулима пиридоксин-хидрохлорида (витамин B6) доводи до промене њихових оптичких својства. Микроструктурна карактеризација синтетисаних наночестица ТiО2 која обухвата трансмисиону електронску микроскопију (ТЕМ) и дифракцију рендгенских зрака (XRD) показала је да наночестице анатаза имају уску дистрибуцију величина са средњим пречником од 45 Å. Праг апсорпције површински модификованих наночестица ТiО2 је за 0,4 еV померен ка већим таласним дужинама у односу на спектар немодификованих честица. Коришћењем FTIR спектроскопије утврђен је начин везивања
витамина B6 за површинске атоме титана. Константа стабилности површинског комплекса је одређена на основу Бенеси–Хилдебрандове (Benesi–Hildebrand) анализе и износи 3,0×102 М-1. Експериментални резултати су поткрепљени детаљним квантно-хемијским прорачунима заснованим на теорији функционала густине (DFT). Утврђен је висок ниво сагласности између апсорпционог спектра наночестица ТiО2 и теоријски добијеног електронског ексцитационог спектра одговарајућег модела.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study, Апсорпција наночестица TiO2 површински модификованих витамином B6 у видљивом делу спектра: упоредна експериментална и DFT студија",
volume = "83",
number = "7-8",
pages = "899-909",
doi = "10.2298/JSC180131044K"
}

Kovač, T., Džunuzović, E. S., Džunuzović, J., Milićević, B., Sredojević, D., Brothers, E. N.,& Nedeljković, J. M.. (2018). Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study. in Journal of the Serbian Chemical Society
Belgrade : Serbian Chemical Society., 83(7-8), 899-909.
https://doi.org/10.2298/JSC180131044K

Kovač T, Džunuzović ES, Džunuzović J, Milićević B, Sredojević D, Brothers EN, Nedeljković JM. Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study. in Journal of the Serbian Chemical Society. 2018;83(7-8):899-909.
doi:10.2298/JSC180131044K .

Kovač, Tijana, Džunuzović, Enis S., Džunuzović, Jasna, Milićević, Bojana, Sredojević, Dušan, Brothers, Edward N, Nedeljković, Jovan M., "Visible light absorption of TiO2 nanoparticles surface-modified with vitamin B-6: A comparative experimental and DFT study" in Journal of the Serbian Chemical Society, 83, no. 7-8 (2018):899-909,
https://doi.org/10.2298/JSC180131044K . .

TY  - JOUR
AU  - Milicevic, Bojana
AU  - Đorđević, Vesna
AU  - Lončarević, Davor
AU  - Dostanić, Jasmina
AU  - Ahrenkiel, Scott Phillip
AU  - Dramićanin, Miroslav
AU  - Sredojević, Dušan
AU  - Svrakic, Nenad M.
AU  - Nedeljković, Jovan M.
PY  - 2017
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2088
AB  - Under normal conditions, titanium dioxide does not absorb visible light photons due to large band gap. Nevertheless, when titanium dioxide nanoparticles (TiO2 NPs) are surface-modified with thiosalicylic acid (TSA), their optical properties are altered owing to the formation of charge transfer complex that initiates absorption in the visible spectral range. Colloidal and sol-gel techniques were used to synthesize uniform TiO2 NPs of different sizes (average diameters in the range 4-15 nm), and effects of their subsequent modification by TSA molecules were compared with effect of modification of commercial Degussa TiO2 powder. Thorough microstructural characterization of TiO2 nanoparticulates was performed including transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis, as well as nitrogen adsorption-desorption isotherms. Optical measurements revealed that all surface-modified TiO2 samples with TSA have similar spectral features independent of their morphological differences, and, more importantly, absorption onset of modified TiO2 samples was found to be red-shifted by 1.0 eV compared to the unmodified ones. The mode of binding between TSA and surface Ti atoms was analyzed by infrared spectroscopy. Finally, the quantum chemical calculations, based on density functional theory, were performed to support optical characterization of surface-modified TiO2 with TSA.
PB  - Elsevier
T2  - Optical Materials
T1  - Charge-transfer complex formation between TiO2 nanoparticles and thiosalicylic acid: A comprehensive experimental and DFT study
VL  - 73
SP  - 163
EP  - 171
DO  - 10.1016/j.optmat.2017.08.011
ER  - 

@article{
author = "Milicevic, Bojana and Đorđević, Vesna and Lončarević, Davor and Dostanić, Jasmina and Ahrenkiel, Scott Phillip and Dramićanin, Miroslav and Sredojević, Dušan and Svrakic, Nenad M. and Nedeljković, Jovan M.",
year = "2017",
abstract = "Under normal conditions, titanium dioxide does not absorb visible light photons due to large band gap. Nevertheless, when titanium dioxide nanoparticles (TiO2 NPs) are surface-modified with thiosalicylic acid (TSA), their optical properties are altered owing to the formation of charge transfer complex that initiates absorption in the visible spectral range. Colloidal and sol-gel techniques were used to synthesize uniform TiO2 NPs of different sizes (average diameters in the range 4-15 nm), and effects of their subsequent modification by TSA molecules were compared with effect of modification of commercial Degussa TiO2 powder. Thorough microstructural characterization of TiO2 nanoparticulates was performed including transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis, as well as nitrogen adsorption-desorption isotherms. Optical measurements revealed that all surface-modified TiO2 samples with TSA have similar spectral features independent of their morphological differences, and, more importantly, absorption onset of modified TiO2 samples was found to be red-shifted by 1.0 eV compared to the unmodified ones. The mode of binding between TSA and surface Ti atoms was analyzed by infrared spectroscopy. Finally, the quantum chemical calculations, based on density functional theory, were performed to support optical characterization of surface-modified TiO2 with TSA.",
publisher = "Elsevier",
journal = "Optical Materials",
title = "Charge-transfer complex formation between TiO2 nanoparticles and thiosalicylic acid: A comprehensive experimental and DFT study",
volume = "73",
pages = "163-171",
doi = "10.1016/j.optmat.2017.08.011"
}

Milicevic, B., Đorđević, V., Lončarević, D., Dostanić, J., Ahrenkiel, S. P., Dramićanin, M., Sredojević, D., Svrakic, N. M.,& Nedeljković, J. M.. (2017). Charge-transfer complex formation between TiO2 nanoparticles and thiosalicylic acid: A comprehensive experimental and DFT study. in Optical Materials
Elsevier., 73, 163-171.
https://doi.org/10.1016/j.optmat.2017.08.011

Milicevic B, Đorđević V, Lončarević D, Dostanić J, Ahrenkiel SP, Dramićanin M, Sredojević D, Svrakic NM, Nedeljković JM. Charge-transfer complex formation between TiO2 nanoparticles and thiosalicylic acid: A comprehensive experimental and DFT study. in Optical Materials. 2017;73:163-171.
doi:10.1016/j.optmat.2017.08.011 .

Milicevic, Bojana, Đorđević, Vesna, Lončarević, Davor, Dostanić, Jasmina, Ahrenkiel, Scott Phillip, Dramićanin, Miroslav, Sredojević, Dušan, Svrakic, Nenad M., Nedeljković, Jovan M., "Charge-transfer complex formation between TiO2 nanoparticles and thiosalicylic acid: A comprehensive experimental and DFT study" in Optical Materials, 73 (2017):163-171,
https://doi.org/10.1016/j.optmat.2017.08.011 . .

TY  - JOUR
AU  - Milicevic, B
AU  - Đorđević, Vesna
AU  - Lončarević, Davor
AU  - Ahrenkiel, Scott Phillip
AU  - Dramićanin, Miroslav
AU  - Nedeljković, Jovan M.
PY  - 2015
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1721
AB  - TiO2 powders with different specific surface area were prepared using reproducible, sol gel synthetic route and their ability to form hybrids with catechol and 5-amino salicylic acid was compared with the commercially available Degussa P25 TiO2 powder. Microstructural characterization involving transmission electron microscopy, X-ray diffraction analysis and nitrogen adsorption-desorption isotherms indicated that TiO2 samples cover reasonably wide size and/or specific surface area range (50-115 m(2)/g). The surface modification of TiO2 powders with catechol and 5-amino salicylic acid induced significant shift of absorption to the visible spectral region due to charge transfer complex formation. It should be emphasized that tunable optical properties of TiO2 in powder form have never been reported in the literature. The largest red shift of the absorption onset was observed for sample with the largest specific surface area upon surface modification with both ligands. The binding of the modifier molecules to the surface Ti atoms was studied using Fourier transform infrared spectroscopy.
PB  - Elsevier
T2  - Microporous and Mesoporous Materials
T1  - Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives
VL  - 217
SP  - 184
EP  - 189
DO  - 10.1016/j.micromeso.2015.06.028
ER  - 

@article{
author = "Milicevic, B and Đorđević, Vesna and Lončarević, Davor and Ahrenkiel, Scott Phillip and Dramićanin, Miroslav and Nedeljković, Jovan M.",
year = "2015",
abstract = "TiO2 powders with different specific surface area were prepared using reproducible, sol gel synthetic route and their ability to form hybrids with catechol and 5-amino salicylic acid was compared with the commercially available Degussa P25 TiO2 powder. Microstructural characterization involving transmission electron microscopy, X-ray diffraction analysis and nitrogen adsorption-desorption isotherms indicated that TiO2 samples cover reasonably wide size and/or specific surface area range (50-115 m(2)/g). The surface modification of TiO2 powders with catechol and 5-amino salicylic acid induced significant shift of absorption to the visible spectral region due to charge transfer complex formation. It should be emphasized that tunable optical properties of TiO2 in powder form have never been reported in the literature. The largest red shift of the absorption onset was observed for sample with the largest specific surface area upon surface modification with both ligands. The binding of the modifier molecules to the surface Ti atoms was studied using Fourier transform infrared spectroscopy.",
publisher = "Elsevier",
journal = "Microporous and Mesoporous Materials",
title = "Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives",
volume = "217",
pages = "184-189",
doi = "10.1016/j.micromeso.2015.06.028"
}

Milicevic, B., Đorđević, V., Lončarević, D., Ahrenkiel, S. P., Dramićanin, M.,& Nedeljković, J. M.. (2015). Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives. in Microporous and Mesoporous Materials
Elsevier., 217, 184-189.
https://doi.org/10.1016/j.micromeso.2015.06.028

Milicevic B, Đorđević V, Lončarević D, Ahrenkiel SP, Dramićanin M, Nedeljković JM. Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives. in Microporous and Mesoporous Materials. 2015;217:184-189.
doi:10.1016/j.micromeso.2015.06.028 .

Milicevic, B, Đorđević, Vesna, Lončarević, Davor, Ahrenkiel, Scott Phillip, Dramićanin, Miroslav, Nedeljković, Jovan M., "Visible light absorption of surface modified TiO2 powders with bidentate benzene derivatives" in Microporous and Mesoporous Materials, 217 (2015):184-189,
https://doi.org/10.1016/j.micromeso.2015.06.028 . .