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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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    Composites of Platinum-Iridium Alloy Nanoparticles and Graphene Oxide for the Dimethyl Amine Borane (DMAB) dehydrogenation at ambient conditions: An Experimental and Density Functional Theory Study
    (Nature Publishing Group, 2019) Sen, Betul; Aygun, Aysenur; Savk, Aysun; Calimli, Mehmet Harbi; Fellah, Mehmet Ferdi; Sen, Fatih
    In this paper, we present the synthesis, characterization, catalytic and computational studies of Composites of Platinum-Iridium Alloy Nanoparticles and Graphene Oxide (PtIr@GO) for dimethylamine borane (DMAB) dehydrogenation. The prepared PtIr@GO nanocatalysts were synthesized using an ethanol super-hydride method, and the characterization procedures for PtIr@GO alloy nanoparticles were carried out by various advanced spectroscopic methods like X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscopy(TEM) and high-resolution transmission electron microscopy (HRTEM). Additionally, catalytic activity, reusability, substrate concentration, and catalyst concentration experiments were performed for DMAB dehydrogenation catalyzed by PtIr@GO alloy nanomaterials. According to the results obtained in this study, PtIr@GO NPs catalyst was found to be active and reusable for the DMAB even at ambient conditions. Besides, DFT-B3LYP calculations have been utilized on PtIr@GO cluster to reveal the prepared catalyst activity. The calculated findings based on DFT was found to be a good agreement with experimental results.
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    Highly monodispersed palladium-ruthenium alloy nanoparticles assembled on poly(N-vinyl-pyrrolidone) for dehydrocoupling of dimethylamine-borane: An experimental and density functional theory study
    (Academic Press Inc Elsevier Science, 2019) Sen, Betul; Aygun, Aysenur; Fellah, Mehmet Ferdi; Calimli, Mehmet Harbi; Sen, Fatih
    This study reports on one of the best heterogeneous catalysts for the dehydrogenation of dimethylamineborane (DMAB). This new catalytic system consists of highly monodisperse Pd and Ru alloy nanoparticles supported by poly(N-vinyl-pyrrolidone) (PdRu@PVP). The prepared heterogeneous catalyst can be reproducibly formed using an ultrasonic reduction technique for DMAB dehydrogenation under mild conditions. For the characterization of PdRu@PVP nanomaterials, several spectroscopic and microscopic techniques were used. The prepared PdRu@PVP nanomaterials with an average particle size of 3.82 +/- 1.10 nm provided an 808.03 h(-1) turnover frequency (TOF) in the dehydrogenation of DMAB and yielded 100% of the cyclic product (Me2NBH2)(2) under mild conditions. Furthermore, the activities of catalysts were investigated theoretically using DFT-B3LYP calculations. The theoretical results based on density functional theory were in favorable agreement with the experimental data. (C) 2019 Elsevier Inc. All rights reserved.