A new highly active polymer supported ruthenium nanocatalyst for the hydrolytic dehydrogenation of dimethylamine-borane

Journal of the Taiwan Institute of Chemical Engineers 99 (2019) 60–65

Contents lists available at ScienceDirect

Journal of the Taiwan Institute of Chemical Engineers journal homepage: www.elsevier.com/locate/jtice

A new highly active polymer supported ruthenium nanocatalyst for the hydrolytic dehydrogenation of dimethylamine-borane Yas¸ ar Karatas¸ a, Aysenur Aygun b, Mehmet Gülcan a,∗, Fatih S¸ en b,∗ a b

Chemistry Department, Faculty of Science, Van Yüzüncü Yıl University, Zeve Campus, 65080 Van, Turkey Sen Research Group, Biochemistry Department, Faculty of Arts and Science, Dumlupınar University, Evliya Çelebi Campus, 43100 Kütahya, Turkey

a r t i c l e

i n f o

Article history: Received 23 November 2018 Revised 21 January 2019 Accepted 23 February 2019 Available online 7 March 2019 Keywords: Dehydrogenation Dimethylamine-borane Nanocatalyst Polyvinylpyrrolidone Ruthenium

a b s t r a c t Herein, we report a highly active Ru@PVP nanocatalyst for the hydrolytic dehydrogenation of dimethylamine-borane under room conditions. The Ru@PVP nanocatalyst was readily prepared, stabilized and used effectively in the catalytic dehydrogenation reaction of dimethylamine-borane in water at room conditions. The prepared Ru@PVP nanocatalyst was characterized using advanced analytical methods such as XPS, XRD, HR-TEM, etc. The characterization analyzes shown that Ru metals are uniformly distributed on the PVP support surface; the mean particle of catalyst size was found to be 2.78 ± 0.16 nm. The catalytic test showed that DMAB had a high catalytic activity with Ru@PVP in aqueous solutions, and TOF value was found to be 2500.52 h−1 for hydrolytic dehydrogenation of DMAB at room conditions. The study also included kinetic data such as activation parameters for different temperatures, catalyst concentration, and substrate concentration experiments. © 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

1. Introduction Today, the safe and efficient storage of hydrogen is a significant problem that must be overcome in hydrogen-related technologies [1,2]. Since hydrogen has a very low density, the liquefaction and transport of hydrogen in room conditions is extremely difficult. Hence, the need for chemicals having high-density for the transportation of hydrogen has increased [3]. To accomplish this, many compounds such as hydrazine (N2 H4 ), ammonia-borane (NH3 BH3 ), sodium borohydride (NaBH4 ), microporous – mesoporous materials, alkyls, some calcium and magnesium borohydrides [4–9] have been used as solid hydrogen materials in nowadays. Boron and nitrogen-based chemicals are more advantageous among these chemicals thanks to their high hydrogen storage capacity. The boron and nitrogen-based compounds have charge and discharge characteristics [10]. Further, the boron and nitrogen-based materials have different attributes concerning porous and hydride materials regarding release and uptake of hydrogen at the ambient conditions. In previous studies [11], the hydrolytic dehydrogenation of DMAB (dimethylamine-borane, (CH3 )2 NHBH3 )) was carried out in room condition and with a suitable catalyst. These studies show that the hydrolytic dehydrogenation of DMAB reaction can be carried out in ∗

Corresponding authors. E-mail addresses: [email protected], [email protected] (M. Gülcan), [email protected], [email protected] (F. S¸ en).

the presence of suitable catalysts at room temperature [12,13]. The high water solubility of DMAB in room conditions ensures that the hydrolytic dehydrogenation of DMAB is advantageous [14]. The hydrolytic dehydrogenation of DMAB in aqueous media yields 3 mol H2 gas from 1 mol of DMAB and is quite stable concerning spontaneous hydrolysis. In contrast, the dehydrogenation of DMAB in organic solvents results in 1 mol of H2 from 1 mol of DMAB [15,16]. Some catalysts tested in the hydrolytic dehydrogenation DMAB have been given in Table 1. Most of the tested catalysts are heterogeneous, and the number of active atoms on their surface is limited. Therefore, the catalytic activity is also reduced because the number of active sites in these catalysts is low. In addition to the heterogeneous catalysts, several semi-heterogeneous catalysts have also been tested in the hydrolytic dehydrogenation of DMAB [17–19]. Mostly, metal nanoparticles are dispersed in water to increase the active surface area, and with the increase of the active surface area, the catalytic activity and the rate of hydrogen released are also increased [20–25]. Hence, metal nanoparticles that can be dispersed in water and used in the hydrolytic dehydrogenation of DMAB reaction need to be developed. For this purpose, in this work, we report the synthesis, catalytic activity and characterization of Ru@PVP nanocatalyst that can be used in water-dispersible and catalytic hydrolytic dehydrogenation of DMAB. The Ru (0) metals in the Ru@PVP nanocatalyst were distributed reasonably well on polyvinylpyrrolidone surface, and it was obtained by reducing the Ru (III) ion to the Ru (0)

https://doi.org/10.1016/j.jtice.2019.02.032 1876-1070/© 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Y. Karatas¸ , A. Aygun and M. Gülcan et al. / Journal of the Taiwan Institute of Chemical Engineers 99 (2019) 60–65 Table 1 Some catalysts used in the hydrolytic dehydrogenation of DMAB and their catalytic performance in turnover frequency (TOF). Catalyst

TOF

∗

Reference

Ru@PVP NiSO4 /Na2 WO4 Carbon supported Pd NiSO4 / KReO4 NiSO4 /Na2 MoO4 Ru NPS Rh NPs@MWCNT

2500.52 4.2 30 3.6 2.8 500 3010.47

This study [23] [16] [23] [21,23] [37] [38]

∗

mol H2 /(mol catalyst × h).

Scheme 1. The catalytic DMAB dehydrogenation in an aqueous medium.

metals in water solution medium. The Ru@PVP nanocatalyst was also used in the hydrolytic dehydrogenation of the DMAB given in Scheme 1. The characterization processes such as surface morphology and critical structure of the Ru@PVP nanocatalyst was elucidated using analytical methods such as XPS, XRD, TEM etc. The TOF value of the catalytic reaction was found to be 2500.52 h−1 by evaluating the kinetics of the catalytic reactions of hydrolytic dehydrogenation of DMAB catalyzed by the Ru@PVP nanocatalyst.

2. Experimental procedure 2.1. Preparation of Ru@PVP nanocatalyst The preparation of the Ru@PVP nanocatalyst was performed according to the alcohol-reduction method improved by Toshima et al. [26]. In this method, a solution of 50 mL H2 O–C2 H6 O was prepared with 200 mg (2.5 mmol, monomeric units) PVP (polyvinylpyrrolidone) and 65.4 mg (0.25 mmol) RuCl3 ·3H2 O (ruthenium (III) chloride trihydrate) mixture. This solution was refluxed for 2 h at 90 °C. The obtained liquid product was stored in colored bottles for use in catalytic reactions.

2.2. The kinetic parameters and kinetic studies of Ru@PVP catalyzed hydrolytic dehydrogenation of DMAB experiments To investigate the effect of the Ru@PVP nanocatalyst on the hydrolytic dehydrogenation of DMAB, three parameters were tested: Temperature, ruthenium concentration and DMAB concentration. Temperature 298 K, 0.25 mM Ru concentration and 1 mM DMAB were taken as common parameters in all experiments. The temperature experiments of the hydrolytic dehydrogenation of DMAB with Ru@PVP nanocatalyst in a 5 mL solution containing DMAB and Ru@PVP nanocatalyst were performed at different temperatures in a range of 298–310 K. The DMAB experiments for the effect of DMAB concentration with Ru@PVP nanocatalyst were carried out at a various DMAB concentration in a range of 100–250 mM at 0.25 mM Ru concentration at 298 K. A set of tests were conducted to determine the effect Ru concentration at different Ru concentration in a range of 1–4 mM with 5 mL solution (1.0 mM DMAB). The kinetic parameters were calculated using the results of temperature experiments and Eyring–Arrhenius graphs [27,28].

61

3. Results and discussion 3.1. The evaluation of the chemical structure of Ru@PVP nanocatalyst As above mentioned, Ru@PVP nanocatalyst was prepared according to the alcohol-reduction method, in the presence of PVP polymer at room temperature. At first, some formation of precipitate-agglomeration in solution medium was seen non-using PVP. In such a case, it can be achieved that the chloride ion is inadequate to stabilize the metal solution. The stabilization of the metal solutions is achieved by using PVP, and the formation of agglomeration or precipitation occurs in a solution medium without PVP. Whereas no agglomeration or precipitate formation was observed in solutions containing PVP supported metal nanoparticles. With this result, it can be concluded that the Ru nanoparticles are stabilized with PVP. On the reduction of Ru (III) ion to Ru (0) metal, the solution of light brown color turned to dark brown in the stabilization process. This result can be seen in UV– vis data (Fig. S1). As seen in the UV–vis spectroscopy results, the d-d transitions of Ru (III) disappear after the reaction, and this result indicates the reduction of Ru (III) into Ru (0). Furthermore, the results of TEM analysis are given in Fig. 1(a). Further, this figure also indicated that the atomic lattice fringe of the prepared nanomaterials was found to be 0.21 nm as expected, which agrees with the (101) lattice spacing of ruthenium [29]. The surface structure of Ru@PVP nanocatalyst was examined by NIH program [30], and their results were given in Fig. 1(b) and it can be concluded that the very well distribution of Ru metals on PVP was shown in Fig. 1(b). The presence of Ru nanometals was also detected by EELS line profile analysis as seen in Fig. 1(c). Nearly 200 particles were counted to indicate the mean particle size of Ru@PVP nanocatalyst; the mean particle size are also given in Fig. 1(b). The mean particle size of the Ru@PVP nanocatalyst was calculated to be 2.78 ± 0.16 nm. Scheme 1 shows the hydrolytic dehydrogenation of DMAB catalyzed with Ru@PVP nanocatalyst. At the end of the catalytic reaction catalyzed with Ru@PVP, the 11 B-NMR analysis has confirmed by the formation of the catalytic reaction products. X-ray photoelectron spectroscopy (XPS) analyzes were also performed to elucidate further the surface structure and oxidation state of the metal in the prepared Ru@PVP nanocatalyst at room temperature. The data of XPS are seen in Fig. 2 (a) and (b). There are two distinctive peaks at 460.5 eV consisting with Ru (0) 3p3/2 in Fig. 2 (a) and (b) [31,32]. The peaks at around 462.9 eV are taken place because of forming RuO2 on Ru@PVP nanocatalyst surface during XPS analysis [31,32]. The morphology and crystalline size of monodisperse Ru@PVP nanoparticles were investigated with the help of X-ray diffraction (XRD) technique. The XRD images of Ru @ PVP and PVP are shown in Fig. 3. The peak at around 23.4° represented the PVP. In addition, Ru (101) crystal planes of a face centered cubic (fcc) structures of ruthenium were observed at around 2θ = 42.2°

3.2. The kinetic studies for DMAB dehydrogenation reaction catalyzed with Ru@PVP nanocatalyst in water The volume of H2 released from DMAB using different Ru@PVP nanocatalyst concentrations at 25 °C is given in Fig. 4. The complete catalytic reaction of DMAB was finished in a short time at room temperature, consisting of the complete hydrolytic dehydrogenation of DMAB given in Scheme 1. The volume of H2 gas evolved from DMAB depending on the Ru@PVP catalyst concentration is given in Fig. 4. As can be seen, the graph of H2 versus time is almost linear. A linear line graph (inset) was obtained when drawing the ln (Ru) graph plotted against ln (k) using the data in Fig. 4, and the slope of this line graph was found to be

62

Y. Karatas¸ , A. Aygun and M. Gülcan et al. / Journal of the Taiwan Institute of Chemical Engineers 99 (2019) 60–65

Fig. 1. (a) TEM analysis; (b) the particle size image of Ru@PVP nanocatalyst (c) EELS line profile of Ru@PVP nanocatalyst.

Fig. 2. (a) Survey scan XPS spectrum of Ru@PVP nanocatalyst; (b) high resolution Ru 3p XPS spectrum of the Ru@PVP nanocatalyst.

Fig. 3. (a) XRD of PVP and Ru@PVP nanocatalyst.

Fig. 4. The time versus (H2 )/(DMAB) ratio for the experiments of DMAB performed at different Ru@PVP nanocatalyst concentrations at room temperature and plot of hydrogen generation rate versus the catalyst concentration (both in logarithmic scale; y = 0.94x – 2.15) (inset).

Y. Karatas¸ , A. Aygun and M. Gülcan et al. / Journal of the Taiwan Institute of Chemical Engineers 99 (2019) 60–65

Fig. 5. The time versus (H2 )/(DMAB) ratio for the experiments with different concentrations of DMAB at room temperature and plot of hydrogen generation rate versus the DMAB concentration (both in logarithmic scale; y = 0.36x – 3.32) (inset).

63

0.94. What the catalytic reaction rate of DMAB depends on Ru@PVP nanocatalyst concentration was found to be about first-order equation. Besides, the effect of DMAB concentration was investigated at the same experimental conditions. Hence, four experiments were conducted with the different DMAB concentration in a range of 100–250 mM. The results of DMAB concentration experiments are given in Fig. 5. And again, the data (H2 /(CH3 )2 NHBH3 ratio) obtained from Fig. 5 were plotted as ln(k) versus ln (CH3 )2 NHBH3 ), a linear graph (inset) was obtained with 0.36 slope value. When this obtained data is evaluated, the DMAB dehydrogenation reaction catalyzed by Ru@PVP nanocatalyst is in about zero-order model. The data of experiments carried out at four different temperatures (298, 303, 308, 318 K) are given in Fig. 6. As seen from the temperature experiments, the hydrogen gas released is increased by increasing the temperature. The initial TOF value for the hydrolytic dehydrogenation of DMAB reaction with Ru@PVP nanocatalyst at room temperature was found to be 2500.52 h−1 , and this TOF value suggests that the hydrolytic dehydrogenation of DMAB is quite well catalyzed by Ru@PVP nanocatalyst.

Fig. 6. (a) The time versus (H2 )/(DMAB) ratio and Arrhenius plot (inset); (b) Eyring plot for Ru@PVP nanocatalyst catalyzed hydrolytic dehydrogenation of DMAB at different temperatures.

64

Y. Karatas¸ , A. Aygun and M. Gülcan et al. / Journal of the Taiwan Institute of Chemical Engineers 99 (2019) 60–65 •

•

•

•

•

Fig. 7. The reusability performance of Ru@PVP nanocatalyst in the hydrolytic dehydrogenation of DMAB at room temperature.

The presence of Ru nano-metals, which provides a uniformly distributed and viable structure on the PVP surface, was studied and demonstrated by methods such as TEM, XPS and XRD. The mean particle size of Ru@PVP nanocatalyst was found to be 2.78 ± 0.36 nm. Ru@PVP nanocatalyst was found to be very effective catalyst in the hydrolytic dehydrogenation of DMAB even at low temperatures (298 K). Ru@PVP nanocatalyst was identified as the catalyst having the highest TOF (2500.52 h−1 ) value among the catalysts used for the hydrolytic dehydrogenation of DMAB at room conditions. Some activation and kinetic parameters (H∗ = 72.61 kJ/mol, S∗ = −14.42 J / (mol × K), Ea = 73.11 kJ/mol) of Ru@PVP nanocatalyst catalyzed for the hydrolytic dehydrogenation of DMAB were calculated. According to the mercury poisoning test results, Ru@PVP nanocatalyst was also found to be a heterogeneous catalyst for the DMAB catalytic sputtering. The Ru@PVP nanocatalyst will have a high potential for fuel cells and other energy sources in the near future with its high catalytic activity and stability properties.

Supplementary materials The activation parameters for the hydrolytic dehydrogenation of DMAB reaction catalyzed by Ru@PVP nanocatalyst was also calculated by using Arrhenius, Eyring equations [33,34] (Fig. 6). The activation enthalpy (H∗ ), entropy (S∗ ) and energy (Ea ) values were found to be 72.61 kJ/mol, −14.42 J / (mol × K) and 73.11 kJ/mol, respectively. The H2 gas - time plot (Fig. 6) of the experiments done at four different temperatures (298, 303, 308, 318 K) is almost linear. Mercury was added to the reaction medium to reveal the effect of mercury poisoning on DMAB dehydrogenation, and a reduction in the catalytic reaction of DMAB efficiency was observed. Hence, the experimental results of mercury poisoning have shown that Ru@PVP nanocatalyst is a heterogeneous catalyst for DMAB dehydrogenation in water [35,36]. To carry out the recyclability experiments, a colorless Ru@PVP nanocatalyst solution was prepared. No activity could be obtained in catalytic reactions of DMAB using only the bulk Ru metals. A solution of 4.064 mM 5 mL of Ru@PVP nanocatalyst is prepared, and the resulting solution and 1.0 mM DMAB was used to measure the catalytic activity of Ru@PVP nanocatalyst in the hydrolytic dehydrogenation of DMAB in the room temperature. Five recycle tests were conducted for this purpose. At the end of each catalytic reaction, the same amount of DMAB was transferred into the reaction vessel, and the reaction started again. The result as% of the recyclability experiments of the hydrolytic dehydrogenation of DMAB is given in Fig. 7 for the Ru@PVP nanocatalyst. On the other hand, Ru@PVP nanocatalyst consisting of uniformly spread Ru on the PVP maintained almost 70% catalytic activity even after the 5th cycle as seen in Fig. 7. According to the obtained experimental data, the Ru@PVP nanocatalyst for the dehydrogenation of DMAB in water has a complementary effect. The Ru@PVP nanocatalyst has the highest TOF among the catalysts used for the same reaction. Some catalysts and their TOF values for the hydrolytic dehydrogenation of DMAB are given in Table 1. This case can be explained by the high stabilization of PVP to metal particles, the increasing active sites of nanomaterials with the help of PVP.

4. Conclusions The findings regarding the hydrolytic dehydrogenation reaction of DMAB with Ru@PVP nanocatalyst are summarized as follows; •

Ru@PVP nanocatalyst is readily prepared by the alcoholreduction method using RuCl3 ·H2 O and PVP polymer.

Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.jtice.2019.02.032. References [1] Rand DAJ, Dell RMJ. The hydrogen economy: a threat or an opportunity for the lead–acid batteries? J Power Sour 2005;144:568–78. [2] Zhang Q, Smith GM, Wu Y. Catalytic hydrolysis of sodium borohydride in an integrated reactor for hydrogen generation. Int J Hydrog Energy 2007;32:4731–5. [3] Sen B, Kuzu S, Demir E, Akocak S, Sen F. Monodisperse palladium-nickel alloy nanoparticles assembled on graphene oxide with the high catalytic activity and reusability in the dehydrogenation of dimethylamine-borane. Int J Hydrog Energy 2017;42(36):23276–83. [4] (a) Friederich A, Drees M, Schneider S. Ruthenium-catalyzed dimethylamine-borane dehydrogenation: stepwise metal-centered dehydrocyclization. Chem Eur J 2009;15:10339–42; (b) Yang X, Sun JK, Kitta M, Pang H, Xu Q. Encapsulating highly catalytically active metal nanoclusters inside porous organic cages. Nat Catal 2018;1:214–20. [5] (a) Wellons MS, Berseth PA, Zidan R. Novel catalytic effects of fullerene for LiBH4 hydrogen uptake and release. Nanotechnology 2009;20(20):204022; (b) Bilen M, Yilmaz O, Guru M. Synthesis of LiBH4 from LiBO2 as hydrogen carrier and its catalytic dehydrogenation. Int J Hydrog Energy 2015;40(44):15213–17; (c) Cao N, Luo W, Cheng G. One-step synthesis of graphene supported Ru nanoparticles as efficient catalysts for hydrolytic dehydrogenation of ammonia borane. Int J Hydrog Energy 2013;38:11964–72. [6] (a) Goksu H, Celik B, Yildiz Y, Kilbas B, Sen F. Superior monodisperse CNT-supported CoPd (CoPd@CNT) nanoparticles for selective reduction of nitro compounds to primary amines with NaBH4 in aqueous medium. Chem Select 2016;1(10):2366–72; (b) Cao N, Su J, Luo W, Cheng G. Hydrolytic dehydrogenation of ammonia borane and methylamine borane catalyzed by graphene supported Ru@Ni core–shell nanoparticles. Int J Hydrog Energy 2014;39:426. [7] (a) Llamas-Jansa I, Friedrichs O, Fichtner M, Bardaji EG, Züttel A, Hauback BC. The role of Ca(BH4 )2 polymorphs. J Phys Chem C 2012;116(25):13472–9; (b) Feng W, Yang L, Cao N, Du C, Cheng G. In situ facile synthesis of bimetallic CoNi catalyst supported on graphene for hydrolytic dehydrogenation of amine borane. Int J Hydrog Energy 2014;39:3371. [8] (a) Zavorotynska O, El-Kharbachi A, Deledda S, Hauback BC. Recent progress in magnesium borohydride Mg(BH4 )2 : fundamentals and applications for energy storage. Int J Hydrog Energy 2016;41:14387–403; (b) Shen J, Yang L, Hu K, Luo W, Cheng G. Rh nanoparticles supported on graphene as efficient catalyst for hydrolytic dehydrogenation of amine boranes for chemical hydrogen storage. Int J Hydrog Energy 2015;40:1062. [9] (a) Xu Q, Chandra M. A portable hydrogen generation system: catalytic hydrolysis of ammonia–borane. J Alloy Compd 2007;446–447:729–732P; (b) Xia B, Liu C, Wu H, Luo W, Cheng G. Hydrolytic dehydrogenation of ammonia borane catalyzed by metal-organic framework supported bimetallic RhNi nanoparticles. Int J Hydrog Energy 2015;40:16391–7. [10] (a) Xu Q, Chandra M. Catalytic activities of non-noble metals for hydrogen generation from aqueous ammonia–borane at room temperature. J Power Sour 2006;163:364; (b) Staubitz A, Robertson APM, Manners I. Ammonia-borane and related compounds as dihydrogen sources. Chem Rev 2010;110:4079–124; (c) Xu Q, Chandra M. Room temperature hydrogen generation from aqueous ammonia-borane using noble metal nano-clusters as highly active catalysts. J Power Sour 2007;168:135–42; (d) Zhan WW, Zhu QL, Xu Q. Dehy-

Y. Karatas¸ , A. Aygun and M. Gülcan et al. / Journal of the Taiwan Institute of Chemical Engineers 99 (2019) 60–65

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19] [20]

[21]

[22]

drogenation of ammonia borane by metal nanoparticle catalysts. ACS Catal 2016;6(10):6892–905. (a) Karkamkar A, Aardahl C, Autrey T. Recent vevelopments on hydrogen release from ammonia-borane. Mater Matters 2007;2:6; (b) Matus MH, Anderson K, Camaioni DM, Autrey T, Dixon DA. Reliable predictions of the thermochemistry of boron-nitrogen hydrogen storage compounds: BxNxHy, x=2,3. J Phys Chem 2007;111(20):4411–21. (a) Chen W, Wang Z, Duan X, Qian G, Chen D, Zhou X. Structural and kinetic insights into Pt/CNT catalysts during hydrogen generation from ammonia-borane. Chem Eng Sci 2018;192:1242–51; (b) Patel N, Fernandes R, Guella G, Miotello A. Nanoparticle-assembled Co-B thin film for the hydrolysis of ammonia borane: a highly active catalyst for hydrogen production. Appl Catal B 2010;95:137–43; (c) Yamada Y, Yano K, Xu Q, Fukuzumi S. Cu/Co3 O4 nanoparticles as catalysts for hydrogen evolution from ammonia borane by hydrolysis. J Phys Chem C 2010;114:16456–62. Zhang J, Chen W, Ge H, Chen C, Yan W, Gao Z, Gan J, Zhang B, Duan X, Qin Y. Synergistic effects in atomic-layer-deposited PtCox/CNTs catalysts enhancing hydrolytic dehydrogenation of ammonia-borane. Appl Catal B: Environ 2018;235:256–63. Jaska CA, Temple K, Lough AJ, Manners I. Transition metal-catalyzed formation of boron-nitrogen bonds: catalytic dehydrocoupling of amine-borane adducts to form amino boranes and borazines. J Am Chem Soc 2003;125:9424–34. (a) Kwan EH, Ogawa H, Yamashita M. A highly active PBP–iridium catalyst for the dehydrogenation of dimethylamine–borane: catalytic performance and mechanism. ChemCatChem 2017;9(13):2457–62; (b) Jaska CA, Temple K, Lough AJ, Manners I. Transition metal-catalyzed formation of boron-nitrogen bonds: catalytic dehydrocoupling of amine-borane adducts to form aminoboranes and borazines. J Am Chem Soc 2003;125:9424–34. (a) Wechsler D, Cui Y, Dean D, Davis B, Jessop PG. Production of H2 from combined endothermic and exothermic hydrogen carriers. J Am Chem Soc 2008;130:17195–203; (b) Keaton RJ, Blacquiere JM, Baker RT. Base metal catalyzed dehydrogenation of ammonia−borane for chemical hydrogen storage. J Am Chem Soc 2007;129:1844–5. Chen Y, Fulton JL, Linehan JC, Autrey T. In-situ spectroscopic studies of rhodium-catalyzed production of hydrogen from dimethylamine borane. homogeneous or heterogeneous catalysis? Prepr Pap Am Chem Soc Div Fuel Chem 2004;49:972–3. Vance JR, Robertson APM, Lee K, Manners I. Photoactivated, iron-catalyzed dehydrocoupling of amine-borane adducts: formation of boron-nitrogen oligomers and polymers. Chem Eur J 2011;17:4099. Stephens FH, Pons V, Baker RT. Ammonia-borane: the hydrogen source par excellence? Dalton Trans 2007;7(25):2613–26. (a) Beweries T, Thomas J, Klahn M, Schulz A, Heller D, Rosenthal U. Catalytic and kinetic studies of the dehydrogenation of dimethylamine borane with an iPr substituted titanocene catalyst. ChemCatChem 2011;3:1865–8; (b) Sloan ME, Clark TJ, Manners I. Homogeneous catalytic dehydrogenation/dehydrocoupling of amine-borane adducts by the Rh (I) Wilkinson’s complex analogue RhCl(PHCy2 )3 (Cy = cyclohexyl). Inorg Chem 2009;48:2429–35. Krutskikh VM, Ivanov MV, Drovosekov AB, Lubnin EN, Lyakhov BF, Polukarov YM. Structural characteristics and catalytic activities of nanocrystalline Ni-Mo-B coatings obtained by catalytic electroless reduction. Prot Met 2007;43:560–6. Jaska CA, Manners I. Heterogeneous or homogeneous catalysis? Mechanistic studies of the rhodium-catalyzed dehydrocoupling of amine-borane and phosphine-borane adducts. J Am Chem Soc 2004;126:9776–85.

65

[23] Drovosekovz AB, Ivanov MV, Krutskikh VM, Polukarov YM. Effect of doping nickel-boron alloys with rhenium, molybdenum, or tungsten on the kinetics of partial reactions of chemical-catalytic reduction of metal ions. Russ J Electrochem 2010;46:136–43. [24] (a) Schätz A, Reiser O, Stark WJ. Nanoparticles as semi-heterogeneous catalyst supports. Chem-A Eur J 2010;16(30):8950–67; (b) Zahmakıran M, Ozkar S. Dimethylammonium hexanoate stabilized rhodium(0) nanoclusters identified as true heterogeneous catalysts with the highest observed activity in the dehydrogenation of dimethylamine-borane. Inorg Chem 2009;48(18):8955–64. [25] Cao A, Luc R, Veser G. Stabilizing metal nanoparticles for heterogeneous catalysis. Phys Chem Chem Phys 2010;12:13499–510. [26] Toshima N, Harada M, Yonezawa T, Kushihashi K, Asakura K. Structural analysis of polymer-protected palladium/platinum bimetallic clusters as dispersed catalysts by using extended x-ray absorption fine structure spectroscopy. J Phys Chem 1991;95:7448–53. [27] Laidler KJ. Chemical kinetics. 3rd edn. UK: Benjamin-Cummings; 1997. [28] Gómez García MÁ, Dobrosz-Gómez I, Ojeda Toro JC. Thermal stability and dynamic analysis of the acetic anhydride hydrolysis reaction. Chem Eng Sci 2016;142:269–76. [29] Yurderi M, Bulut A, Zahmakiran M, Gülcan M, Özkar S. Ruthenium(0) nanoparticles stabilized by metal-organic framework (ZIF-8): highly efficient catalyst for the dehydrogenation of dimethylamine-borane and transfer hydrogenation of unsaturated hydrocarbons using dimethylamine-borane as hydrogen source. Appl Catal B: Environ 2014;160–161:534–41. [30] Hutchison JE, Woehrle GH, Özkar S, Finke RG. Analysis of nanoparticle transmission electron microscopy data using a public-domain image-processing program. Image Turk J Chem 2006;30:1–13. [31] Sen B, Kuyuldar E, Demirkan B, Onal Okyay T, Savk A, Sen F. Highly efficient polymer supported monodisperse ruthenium-nickel nanocomposites for dehydrocoupling of dimethylamine-borane. J Colloid Interface Sci 2018;526:480–6. [32] Durak H, Gulcan M, Zahmakiran M, Ozkar S, Kaya M. Hydroxyapatite– nanosphere supported ruthenium(0) nanoparticle catalyst for hydrogen generation from ammonia-borane solution: kinetic studies for nanoparticle formation and hydrogen evolution. RSC Adv 2014(4):28947–55. [33] Wood DA. Thermal maturity and burial history modeling of shale is enhanced by the use of Arrhenius time-temperature index and memetic optimizer. Petroleum 2018;4(1):25–42. [34] Bonnet L, Rayez JC. Dynamical derivation of the Eyring equation and the second-order kinetic law. Int J Quantum Chem 2010;110(13):2355–9. [35] Whitesides GM, Hackett M, Brainard RL, Lavalleye JP, Sowinski AF, Izumi AN, Moore SS, Brown DW, Staudt EM. Suppression of unwanted heterogeneous platinum(0)-catalyzed reactions by poisoning with mercury(0) in systems involving competing for homogeneous reactions of soluble organoplatinum compounds: thermal decomposition of bis(triethylphosphine)-3,3,4,4-tetramethylplatinacyclopentane. Organometallics 1985;4:1819–30. [36] Widegren JA, Finke RG. A review of the problem of distinguishing true homogeneous catalysis from soluble or another metal-particle heterogeneous catalysis under reducing conditions. J Mol Catal A: Chem 2003;198:317–41. [37] Caliskan S, Zahmakiran M, Durap F, Özkar S. Hydrogen liberation from the hydrolytic dehydrogenation of dimethylamine-borane at room temperature by using a novel ruthenium nanocatalyst. Dalton Trans 2012;41:4976–84. [38] Günbatar S, Aygun A, Karatas¸ Y, Gülcan M, S¸ en F. Carbon-nanotube-based rhodium nanoparticles as highly-active catalyst for hydrolytic dehydrogenation of dimethylamineborane at room temperature. J Colloid Interface Sci 2018;530:321–7.