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Article Citation - WoS: 24Citation - Scopus: 28Palladium(0) Nanoparticles Supported on Hydroxyapatite Nanospheres: Active, Long-Lived, and Reusable Nanocatalyst for Hydrogen Generation From the Dehydrogenation of Aqueous Ammonia-Borane Solution(Springer, 2014) Karatas, Yasar; Yurderi, Mehmet; Gulcan, Mehmet; Zahmakiran, Mehmet; Kaya, MuratAmong the solidmaterials considered in the chemical hydrogen storage, ammonia-borane (NH3-BH3) appears to be one of the promising candidates as it can release hydrogen throughout hydrolysis in the presence of suitable catalyst under mild conditions. Herein we report, for the first time, the preparation and characterization of palladium(0) nanoparticles supported on nanohydroxyapatite and their catalytic use in the hydrolysis of ammonia-borane under air at room temperature. These new palladium(0) nanoparticles were generated in situ during the catalytic hydrolysis of ammonia-borane starting with palladium(II) immobilized nanohydroxyapatite. The preliminary characterization of the palladium(0) nanoparticles supported on nanohydroxyapatite was done by the combination of complimentary techniques, which reveals that the formation of well-dispersed Pd(0)NPs nanoparticles (1.41 +/- 0.52 nm) on the surface of hydroxyapatite nanospheres (60-150 nm). The resulting palladium nanocatalyst achieves hydrogen generation from the hydrolysis of ammonia-borane with an initial turnover frequency value (TOF) of 11 mol H-2 mol(-1) Pd x min at room temperature under air. In addition to their high activity, the catalytic lifetime experiment showed that they can also act as a long-lived heterogeneous catalyst for this reaction (TTON = 14,200 mol H-2 mol(-1) Pd) at room temperature under air. More importantly, nanohydroxyapatite- supported palladium(0) nanoparticles were found to be highly stable against to leaching and sintering throughout the catalytic runs that make them isolable, bottleable, and reusable heterogeneous catalyst for the hydrolysis of ammonia-borane.Article Citation - WoS: 8Citation - Scopus: 8Thermoluminescence Properties of Zno Nanoparticles in the Temperature Range 10-300 K(Springer, 2016) Isik, M.; Yildirim, T.; Gasanly, N. M.Low-temperature thermoluminescence (TL) properties of ZnO nanoparticles grown by sol-gel method were investigated in the 10-300 K temperature range. TL glow curve obtained at 0.2 K/s constant heating rate exhibited one broad peak around 83 K. The observed peak was analyzed using curve fitting method to determine the activation energies of trapping center(s) responsible for glow curve. Analyses resulted in the presence of three peaks at 55, 85 and 118 K temperatures with activation energies of 12, 30 and 45 meV, respectively. Thermal cleaning process was applied to separate overlapped peaks and get an opportunity to increase the reliability of results obtained from curve fitting method. Heating rate dependence of glow curve was also studied for rates between 0.2 and 0.7 K/s. The shift of the peak maximum temperatures to higher values and decrease in peak height with heating rate were observed. Moreover, X-ray diffraction and scanning electron microscopy were used for structural characterization.
