Supplementary data for the article: Dimitrijević, T.; Vulić, P.; Manojlović, D.; Nikolić, A. S.; Stanković, D. M. Amperometric Ascorbic Acid Sensor Based on Doped Ferrites Nanoparticles Modified Glassy Carbon Paste Electrode. Analytical Biochemistry 2016, 504, 20–26. https://doi.org/10.1016/j.ab.2016.03.020

Supplementary material for: [https://doi.org/10.1016/j.ab.2016.03.020]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1950

Effects of Gd3+ co-doping on NaYF4:Yb,Er nanoparticles structure

NaYF4 doped with Rare Earth elements such as Yb and Er is well known as a compound with the remarkable up-conversion photoluminesce and wide application. In this work, the influence of additional co-doping of NaYF4:Yb,Er with gadolinium (0, 15 and 30 mol%) was explored. The syntheses were performed solvothermally using the mixture of water/ethanol as medium and polyvinylpyrrolidone (PVP) as capping ligand. The obtained powders were subjected to X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and photoluminesce (PL) analyses. Structural refinement shown that NaYF4:Yb,Er particles generally crystallized in a cubic form (Fm-3m), while the additional presence of Gd3+ in the crystal lattice lead to the pure hexagonal phase crystallization (P63/m). Morphological analyses revealed that all powders are composed from nanodimensional particles with the size in the range of 50-70 nm, while FTIR spectra confirmed the presence of PVP functional groups on the particles surfaces. The strongest effect of Gd3+ doping was notices in the PL spectra, where the up-conversion response increases with the mol% of this dopant

The usage of different fluoride sources during solvothermal synthesis of UCNPs in hydroxyl-carboxyl chelated precursor

There is a great interest for the synthesis of rare earth (RE) doped up-converting nanoparticles (UCNPs) which morphological and luminescence properties are well suited for application in optoelectronics, forensics, security and biomedicine. The synthesis of such particles usually comprises decomposition of organometallic compounds in an oxygen-free environment followed with coating of biocompatible layer or ligands exchange. In this work hydroxyl-carboxyl (HO-C) type of chelators (citric acid and sodium citrate) are used for the stabilization of NaYF4:Gd,Yb,Er UCNPs during solvothermal treatment of rare earth nitrate salts with different fluoride sources (NaF, NH4F and NH4HF2). The x-ray powder diffraction (XRPD) showed that all powders contain the mixture of cubic and hexagonal NaYF4:Gd,Yb,Er phase in nano and micro-sized particles respectively. However, the content of later one prevails in samples obtain when Nacitrate is used as chelator, regardless of which fluoride source is used for precipitation. Additionally, variation of the particles size and shape is detected with a variation of fluoride type. All particles have hydrophilic surface due to retention of citrate ligands and emit intense green light emission centered at 519 and 539 nm (2H11/2,4S3/2→4I15/2) when excited with near infrared light

Supplementary data for the article: Ilić, I.; Milutinović-Nikolić, A.; Mojović, Z.; Vuković, Z.; Vulić, P.; Gržetić, I.; Banković, P.; Jović-Jovičić, N. Oxidative Degradation of Aromatic N-Compounds Using Cobalt Containing Montmorillonite-Based Catalysts. Applied Clay Science 2020, 193, 105668. https://doi.org/10.1016/j.clay.2020.105668

Supplementary material for: [https://doi.org/10.1016/j.clay.2020.105668]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/4045

Influence of Gd3+ doping on the NaYF4 :YB3+,ER3+ structural and up-conversion properties

application as lasers, displays, photo-thermal agents and biomarkers. Due to efficient two-phonon excitation and the large anti-Stocks shift UCNPs are able to emit visible or UV photons under excitation by near-infrared (NIR). Over the last decade, decomposition of organometallic compounds has been indicated as one of the most convenient method for the synthesis of monodisperse NaYF4:Yb3+,Er3+ UCNPs with a hexagonal crystal structure. Herein, NaY0.8-xGdxYb0.18Er0.02F4 (x= 0.3 or 0.15) up-conversion nanoparticles crystallized in the hexagonal space group P63/m were successfully synthesized solvothermally utilizing rare earth nitrates, NaF and polyvinylpyrrolidone (PVP) in ethanol-water mixture at 200 °C. Rietveld refinement of the X-ray powder diffraction (XRPD) data and high resolution transmission microscopy (HRTEM) analysis show that all UCNPs are monocrystalline (60-70 nm), have low defect concentration and uniform dopants distribution. Fourier-transform infrared (FTIR) spectroscopy indicate existence of the PVP ligands at the UCNPs surface, while photoluminescence (PL) spectra shows characteristic green (at 520 and 540 nm, due to 2H11/2, 4S3/2→4I15/2 transitions) and red (at 655 nm, due to 4F9/2 → 4I15/2 transition) emission lines under excitation by NIR (λ =980 nm) light

Supplementary data for the article: Dimitrijević, T.; Vulić, P.; Manojlović, D.; Nikolić, A. S.; Stanković, D. M. Amperometric Ascorbic Acid Sensor Based on Doped Ferrites Nanoparticles Modified Glassy Carbon Paste Electrode. Analytical Biochemistry 2016, 504, 20–26. https://doi.org/10.1016/j.ab.2016.03.020

Supplementary material for: [https://doi.org/10.1016/j.ab.2016.03.020]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1950

Characterization of MgAl2O4 Sintered Ceramics

Single phase MgAl2O4 was made from a one-to-one molar ratio of MgO and Al2O3 powders mixed using ball-milling. Mixtures of MgO and Al2O3 were subsequently treated in planetary ball mill for 30, 60, 90 and 120 minutes in air. The aim of this study was to examine phase composition, microstructure, and densification behavior of sintered specimens. After sintering in dilatometer at 1500 degrees C, the powder was converted to single phase MgAl2O4. The results show that mechanical activation improved the densification behavior of MgAl2O4 sintered specimens, and it reduced the onset temperature for sintering by approx. 100 degrees C. Based on dilatometer data, powders were subsequently densified at 1450 degrees C by hot pressing. Almost all specimens exhibited full density, while sample activated for 30 minutes showed the fastest densification rate

Characterization of MgAl2O4 sintered ceramics

Single phase MgAl2O4 was made from a one-to-one molar ratio of MgO and Al2O3 powders mixed using ball-milling. Mixtures of MgO and Al2O3 were subsequently treated in planetary ball mill for 30, 60, 90 and 120 minutes in air. The aim of this study was to examine phase composition, microstructure, and densification behavior of sintered specimens. After sintering in dilatometer at 1500 °C, the powder was converted to single phase MgAl2O4. The results show that mechanical activation improved the densification behavior of MgAl2O4 sintered specimens, and it reduced the onset temperature for sintering by approx. 100 oC. Based on dilatometer data, powders were subsequently densified at 1450 oC by hot pressing. Almost аll specimens exhibited full density, while sample activated for 30 minutes showed the fastest densification rate