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    Bimetallic platinum-rhodium nanocomposites for dimethylamine borane dehydrogenation: an experimental and density functional theory study
    (Royal Soc Chemistry, 2020) Alptekin, Oznur; Sen, Betul; Acidereli, Hilal; Ercetin, Umran; Fellah, Mehmet Ferdi; Sen, Fatih
    In this study, bimetallic platinum-rhodium nanocomposites supported on graphene oxide (PtRh@GO) were synthesized and used as a catalyst in the dimethylamine borane (DMAB) dehydrogenation. The synthesized PtRh@GO catalyst was characterized using spectral and microscopic methods. The characterization studies revealed that the obtained PtRh@GO nanomaterials were nano-sized and exhibited a monodisperse distribution on GO. As a result of the catalytic studies, it was determined that the dehydrogenation reaction of dimethylamine borane depends on the temperature, amount of catalyst, and substrate. Additionally, some kinetic data and activation parameters were investigated for the dimethylamine dehydrogenation of DMAB with the help of PtRh@GO. The kinetic and activation parameters showed that the PtRh@GO catalyst could be used effectively. The activation energy (E-a) was found to be 17 +/- 2 kJ mol(-1)for the dimethylamine borane dehydrogenation. Using previously performed studies, comparison studies for the turnover frequency (TOF) value of the PtRh@GO catalyst in the dimethylamine borane reaction showed that the obtained PtRh@GO catalyst could be used effectively with a higher TOF (274.6 h(-1)) value. In addition, DFT computations were utilized on the structure of PtRh@GO in order to investigate the activity of the catalyst. The experimental data have been supported by the theoretical results based on DFT.
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    Use of silica-based homogeneously distributed gold nickel nanohybrid as a stable nanocatalyst for the hydrogen production from the dimethylamine borane
    (Nature Publishing Group, 2020) Alptekin, Oznur; Sen, Betul; Savk, Aysun; Ercetin, Umran; Mustafov, Sibel Demiroglu; Fellah, Mehmet Ferdi
    In this study, the effects of silica-based gold-nickel (AuNi@SiO2) nanohybrid to the production of hydrogen from dimethylamine borane (DMAB) were investigated. AuNi@SiO2 nanohybrid constructs were prepared as nanocatalysts for the dimethylamine borane dehydrogenation. The prepared nanohybrid structures were exhibited high catalytic activity and a stable form. The resulting nanohybrid, AuNi@SiO2 as a nanocatalyst, was tested in the hydrogen evolution from DMAB at room temperature. The synthesized nanohybrids were characterized using some analytical techniques. According to the results of the characterization, it was observed that the catalyst was in nanoscale and the gold-nickel alloys showed a homogenous distribution on the SiO2 surface. After characterization, the turn over frequency (TOF) of nanohybrid prepared for the production of hydrogen from dimethylamine was calculated (546.9 h(-1)). Also, the prepared nanohybrid can be used non-observed a significant decrease in activity even after the fifth use, in the same reaction. In addition, the activation energy (Ea) of the reaction of DMAB catalyzed AuNi@SiO2 nanohybrid was found to be 16.653 +/- 1 kJ mol(-1) that facilitated the catalytic reaction. Furthermore, DFT-B3LYP calculations were used on the AuNi@SiO2 cluster to investigate catalyst activity. Computational results based on DFT obtained in the theoretical part of the study support the experimental data.