CuNi Nanoparticles Assembled on Graphene for Catalytic

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CuNi Nanoparticles Assembled on Graphene for Catalytic Methanolysis of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds Chao Yu, Jiaju Fu, Michelle Muzzio, Tunli Shen, Dong Su, Junjie Zhu, and Shouheng Sun Chem. Mater., Just Accepted Manuscript • DOI: 10.1021/acs.chemmater.6b05364 • Publication Date (Web): 12 Jan 2017 Downloaded from http://pubs.acs.org on January 20, 2017

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Chemistry of Materials

CuNi Nanoparticles Assembled on Graphene for Catalytic Methanolysis of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds †

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Chao Yu, Jiaju Fu, Michelle Muzzio, Tunli Shen, Dong Su, Junjie Zhu, and Shouheng Sun*, †

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Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.

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State Key Laboratory of Analytical Chemistry for Life Science, Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China. ₤

Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, United States.

ABSTRACT: We report a solution phase synthesis of 16 nm CuNi nanoparticles (NPs) with the Cu/Ni composition control. These NPs are assembled on graphene (G) and show Cu/Ni composition-dependent catalysis for methanolysis of ammonia borane (AB) and hydrogenation of aromatic nitro (nitrile) compounds to primary amines in methanol at room temperature. Among five different CuNi NPs studied, the G-Cu36Ni64 NPs are the best catalyst for both AB methanolysis (TOF = 49.1 molH2 molCuNi-1 min-1 and Ea = 24.4 kJ/mol) and hydrogenation reactions (conversion yield >97%). The G-CuNi represents a unique noble-metal-free catalyst for hydrogenation reactions in a green environment without using pure hydrogen.

Advances in nanoparticle (NP) synthesis methodology have made it possible to develop many different kinds of NPs with dimension and composition controls at near-atom-precision. Such controls allow the rational tuning and optimization of physical and chemical properties of NPs for optical, magnetic, biomedical and catalytic applications.1-6 Recently, monodisperse NPs have attracted even more attention as catalysts for energy conversions and other important chemical reactions.7-13 The precise dimension controls achieved from the syntheses render these NPs ideal candidates for studying both electronic and geometric effects on a specific reaction and for identifying catalytic active sites on the NP surface to optimize catalytic activity and selectivity.14-17 The monodisperse NPs can also be assembled on a graphene (G) surface, and NP-G interactions, as well as the strong adsorption power of the G surface, can be exploited to promote the catalytic reaction and to enrich the reactants around the NP proximity, further enhancing the NP catalysis.18-22 Here we report the synthesis of CuNi alloy NPs, their assembly on G, and their catalysis for tandem methanolysis of ammonia borane (AB, BH3•NH3) and hydrogenation of nitro (R-NO2) or nitrile (R-CN) compounds to primary amines. AB has been explored extensively as a new hydrogen storage material (19.6 wt% hydrogen content) for easy hydrogen transportation.23-31 Hydrogen is released via AB hydrolysis or methanolysis, both of which can be catalyzed by a nanostructured catalyst of noble metal13, 32-34 or first-row transition metal Ni (or Cu) in ambient conditions.35-38 Recently, this reaction was found to show good reducing power to convert R-NO2 to R-NH2 or R-CN to R-CH2NH2 in the presence a noble metal catalyst, especially MPd alloy NPs (M = Ni, Co, Fe) deposited on G,24, 39-42 opening up a new

approach to the production of primary amines without using pure hydrogen at elevated temperature and high pressure conditions.43-47 Working to develop a noble-metal-free catalyst for the same tandem reaction, we found the CuNi alloy NPs deposited on G, denoted as G-CuNi, showed Cu/Ni composition-dependent catalysis in methanol at room temperature. Among 5 different kinds of CuNi NPs studied, the G-Cu36Ni64 showed the best catalytic activity and recyclability toward the methanolysis of AB with superior initial turnover frequency (TOF) and lowest Arrhenius activation energy. In the same reaction environment, the G-Cu36Ni64 also served as an efficient catalyst to catalyze the hydrogenation of R-NO2 or R-CN into the corresponding primary amines with the conversion yield >97%. Monodisperse CuNi NPs were prepared by the co-reduction of nickel(II) acetylacetonate (Ni(acac)2) and copper (II) acetylacetonate (Cu(acac)2) with borane-t-butylamine (BBA) in oleylamine (OAm) and oleic acid (OA). BBA served as the reducing agent, while OAm functioned as both a solvent and a surfactant. OA was added as a co-surfactant for the CuNi NP stabilization. The metal contents of the CuNi NPs were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Cu36Ni64 NPs were obtained by reducing 0.26 mmol of Ni(acac)2 and 0.14 mmol of Cu(acac)2. Figure 1A is a representative TEM image of the as-synthesized of Cu36Ni64 NPs. The NPs have an average diameter of 16.0 ± 1.0 nm. Figure 1B shows a high-resolution TEM (HRTEM) image of a single Cu36Ni64 NP, showing the interfringe distance of 2.05 Å, smaller than the Cu (111) spacing at 2.088 Å but larger than the Ni (111) spacing at 2.034 Å. The face centered cubic (fcc) type solid solution structure of the Cu36Ni64 NPs was confirmed by the X-ray diffraction (XRD) pattern (Figure

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S1). The alloy structure was further characterized by high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). Figure 1C shows the HAADF-STEM image of the Cu36Ni64 NPs and the STEM-EELS elemental mapping of a selected Cu36Ni64 NP and Figure S2 is the STEM-EELS line scan across one 16 nm Cu36Ni64 NP, all of which indicate that Cu and Ni distribute evenly in the NP.

Figure 1. (A) TEM image of the as-prepared Cu36Ni64 NPs. (B) HRTEM image of a single Cu36Ni64 NP. (C) HAADF-STEM image of the Cu36Ni64 NPs (scale bar: 10 nm) and STEM-EELS elemental mapping of a selected NP to show Ni (green) and Cu (red) distribution within the NP. (D) TEM image of the BAtreated G-Cu36Ni64 NPs.

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symmetric (3372 cm−1) and asymmetric vibrations (3296 cm−1), while the BA-treated sample shows no such peaks. The TEM image analysis on the BA-treated G-Cu36Ni64 further suggests that this BA-treatment procedure did not affect the size and morphology of the NPs (Figure 1D). The NPs stay at 16 ± 1 nm and are still well-dispersed on the G surface. Cu/Ni composition-dependent methanolysis of AB was studied in methanol at room temperature with catalyst and AB concentrations being kept constant as reported in the AB methanolysis50-52 for easy comparisons between the new CuNi and other NP systems. Figure 2A shows the methanolysis data from G-CuNi with different Cu/Ni compositions from which we can see that G-Cu36Ni64 is the most active catalyst in the current test condition. As a control, we also prepared G-Cu and G-Ni NPs for the methanolysis of AB. As shown in Figure S5, the Ni catalyst is much more active than the Cu one. The TOF values of G-Ni and G-Cu were calculated to 16.0 and 1.4 molH2 molcatalyst-1•min-1, respectively. Comparing these with the data shown in Figure 2A, we can see that the CuNi alloy NPs are the better catalyst than either the Cu or Ni NPs. This catalytic enhancement should result from the alloy effect that is often observed to show a certain degree of enhancement in catalysis compared to the elemental counterparts.53,54 The calculated d-band centers of Cu and Ni are −2.67 eV and −1.29 eV, respectively.55 Once the CuNi alloy is formed, the d-band center position of the alloy should shift to between Cu and Ni. This d-band shift may further optimize the bonding between bimetallic surface and reacting species for catalysis.56,57 Using the reported solution phase synthesis, we are able to control the CuNi alloy compositions and to engineer the electronic structure of the alloy to optimize the NP catalysis.

The Cu/Ni compositions of the final CuNi NPs were controlled by the initial molar ratios of Cu and Ni salts. Cu75Ni25, Cu68Ni32, Cu51Ni49, Cu36Ni64 and Cu24Ni76 NPs were obtained from the Cu/Ni molar ratios of 3:1, 2:1, 1:1, 1:2 and 1:3 respectively. Figure S3 shows more representative TEM images of the CuNi NPs with different compositions. They are all in the 15-16 nm size range - for example, the average sizes of the Cu75Ni25 and Cu24Ni76 NPs are 15.8 nm and 15.0 nm, respectively. Such a narrow size variation among different CuNi NPs allows us to study composition-dependent activities of the NPs. To test the NPs as the catalyst for the methanolysis of AB, we first assembled the pre-weighed CuNi NPs on 18 mg G through the sonication of the ethanol dispersion of G and the hexane dispersion of NPs to produce G-CuNi (SI). The CuNi NPs were then activated by immersing the NPs in tbutylamine (BA). The mixture in the flask was pre-purged with N2, sealed with septa rubber and stirred for 3 days. The solid product was separated by centrifugation and washed with ethanol.11, 20, 48, 49 This process could also be applied to prepare C- and SiO2-NPs. Infrared (IR) spectroscopy was used to characterize the OAm/OA removal. To avoid the G- or Chydrocarbon background interference with the spectra, the SiO2-CuNi was specifically selected for the characterization purpose. IR spectra of the SiO2-Cu36Ni64 NPs (Figure S4) show that the pre-treated NP sample has the characteristic – C=C (1658 cm−1), =C-H (3010 cm−1), as well as the NH2

Figure 2. (A) Plot of time vs volume of H2 generated from AB methanolysis catalyzed by G-CuNi with different Cu/Ni compositions (CuNi NPs = 9.8 mM, [AB] = 300 mM, T = 298 K). (B) Stoichiometric hydrogen evolution from AB methanolysis catalyzed by G-Cu36Ni64 at different catalyst concentrations ([AB] = 300 mM, T = 298 K). Inset: Logarithmic plots of reaction rate vs [CuNi]. (C) Stoichiometric hydrogen evolution at different AB concentrations ([CuNi] = 9.8 mM, T = 298 K). Inset: Logarithmic plots of rate vs [AB]. (D) Plot of time vs volume of hydrogen generated at different temperatures ([AB] = 300 mM, [CuNi] = 9.8 mM). Inset: Arrhenius plot of ln k vs (1000/T).

In addition, we also tested the support effect. CuNi NPs without any support are less active than the G-CuNi NPs but


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show the same Cu/Ni composition-dependent activity trend as the G-CuNi NPs with the Cu36Ni64 NPs being the most active (Figure S6). Similar tests showed that C-Cu36Ni64 NPs and SiO2-Cu36Ni64 NPs were less active than the G-Cu36Ni64 NPs (Figure S7), demonstrating the effect of G on promoting the NP catalysis. The reaction kinetics of the G-Cu36Ni64 catalyst was further studied. In one group of the tests, AB concentration was kept at 300 mM but the CuNi NP concentrations were varied to be 3.8-9.8 mM. The methanolysis kinetic plots were given in Figure 2B and the corresponding inset. In another group of the tests, the NP loading was fixed at 9.8 mM but the AB concentrations were varied from 200 to 350 mM (Figure 2C and inset). We can see that in these two groups of tests, H2 is fastreleased within minutes and the H2 volume released from the reaction is linearly related to the concentration of AB or Cu36Ni64. The reaction is first-order with respect to the NP concentration (Figure 2B) and half-order with respect to the AB concentration (Figure 2C), which is different from the zero-order dependence to AB on Pd,51,58,59 or the first-order dependence to AB on the Ru surface,60 but is similar to the AB hydrolysis on Ni.61 It was hypothesized that the half-order to AB on Ni NPs was attributed to Ni NP dissolution and Ni cations re-reduction during the hydrolysis process, leading to the formation of smaller Ni NPs and unique half-order reaction kinetics to the AB concentration. Similar NP composition (Table S1) and morphology (Figure S8) changes were also observed in the current CuNi catalysis for AB methanolysis, indicating that such metal dissolution and reduction is key to the observation of the half-order methanolysis kinetics to the AB concentration.

Figure 3. Initial catalytic activity change of the BA-treated (black) and non-BA-treated G-Cu36Ni64 (blue) in successive reaction cycles ([Cu36Ni64] = 9.8 mM, [AB] = 300 mM, T = 298 K).

The catalytic activity of the G-Cu36Ni64 NPs was characterized by turnover frequency (TOF) of the reaction. The highest TOF of the G-Cu36Ni64 was calculated to be 49.1 molH2 molCu-1 -1 when Cu36Ni64/AB molar ratio was at 0.033. This Ni •min value is the highest among the Cu-, Ni- or even most of the noble metal catalysts (Table S2-S4).62-64 The methanolysis activation energy was evaluated by measuring the temperature-dependent hydrogen formation in the temperature range 298 K-323 K (Figure 2D and the inset), from which the Arrhenius plot was obtained and the activation energy was calculated to be Ea = 24.4 kJ/mol. This is lowest activation energy value reported among non-noble metal catalysts, and close to the smallest values achieved by some of the most active noblemetal catalysts (Table S5).65-67

The stability of the G-Cu36Ni64 was tested by the repeated use of the same catalyst for the new run of methanolysis reaction. After every 30 min when H2 generation was completed, another equivalent of AB (3 mmol) was added to the reaction system and the results were recorded, as shown in Figure 3. The catalyst shows almost no activity change in the first 4 runs. After the 10th cycle, the catalyst still remains the alloy structure (Figure S9) and the activity keeps at 80 % of the initial catalytic activity. We attribute this degradation to the CuNi NP change (Table S1 and Figure S8) and to the weak GNP interaction, which competes with the NH3-NP interaction during the reaction. This is further supported by the catalysis of the as-synthesized, non-BA-treated G-Cu36Ni64 NPs, which show even poorer stability (Figure 3 and Figure S10) despite that they are as active as the BA-treated ones initially. This indicates that the OAm/OA coating does not reduce the NP catalysis, but it does make the NPs less stable on the G surface. We expect that the stability of these CuNi NPs should be further improved once the G-NP interactions are enhanced by introducing, for example, N-doping in the G network. Table 1. G-Cu36Ni64-catalyzed tandem reduction of nitro and nitrile compounds

The excellent performance of the G-Cu36Ni64 for the AB methanolysis motivated us to use the catalyst and the reaction to reduce R-NO2/R-CN into primary amines in methanol. We should note that the use of methanol as the solvent in this work is different from what has been published, where methanol + water was used as the mixed solvent for the hydrogenation reaction. Our initial tests shown in Table S6 indicated that the presence of water in the reaction system degraded the NP catalytic activity. In the current hydrogenation reaction test in methanol, R-NO2 or R-CN/AB was set at 1:3 mol/mol at room temperature and the reaction was sealed by a balloon to prevent hydrogen from escaping from the reaction system. Thin layer chromatography (TLC) was used to monitor the reaction process and gas chromatography-mass spectrometry (GC-MS) was used to quantify the reaction mixture changes. Table 1 summarizes the results obtained from the G-Cu36Ni64 catalyzed hydrogenation of a few representative R-NO2/R-CN com-



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pounds. It is noteworthy that the mono-NO2 and CN compounds are hydrogenated into the corresponding amines with the reaction conversion yield reaching above 97 % in 30 min. Hydrogenation of di-NO2 to di-NH2 required 120 min for the conversion to complete. When CN and NO2 co-exist, NO2 is selectively reduced to NH2 while CN is intact. This selective reduction is consistent with what is reported on the MPd catalyst, indicating that the π-donor conjuration raises the CN activation energy barrier, making it impossible to reduce CN in the current reaction condition.24 The new G-Cu36Ni64 catalyst can be compared favorably with MPd or other catalysts reported for the same reaction, as shown in Table S7. After the fifth consecutive reaction cycle, the catalyst still showed the conversion yield higher than 97 % in the same reaction time (Figure S11). We further tested the reaction in an open (to air) system or under a gentle flow of N2. In both cases, the reaction led to a low conversion yield below 20 %. Moreover, if only one equiv of AB was present in the reaction mixture, the conversion yield decreased to 34 %. These indicate that H2 generated insitu plays an important role in the hydrogenation reaction and excess of H2 is needed to complete the conversion in the current reaction condition. The reaction without the presence of the catalyst showed no sign of the conversion. In summary, 16 nm CuNi NPs with controlled size, shape and composition were synthesized and assembled on G. The NPs are activated by washing with t-butylamine and ethanol at room temperature. The G-CuNi NPs show the Cu/Ni composition-dependent AB methanolysis. Among different G-CuNi NPs studied in this work, the G-Cu36Ni64 NPs are the most active catalyst with TOF = 49.1 molH2 molCuNi-1 min-1 and Ea = 24.4 kJ/mol. The catalyst shows the desired durability, retaining 80 % of its initial activity after the 10th cycle. The GCu36Ni64 catalyst was also active for Ar-NO2 (or (Ar-CN) hydrogenation to Ar-NH2 (or Ar-CH2NH2) in the AB methanolysis condition with excellent conversion yield (>97%). Therefore, the G-Cu36Ni64 NPs act as a dual catalyst for both AB methanolysis to H2 and Ar-NO2 (or Ar-CN) hydrogenation to primary amines. The G-CuNi represents a unique noble-metalfree catalyst for hydrogenation reactions in a green environment without using the pure hydrogen. Studies of its catalysis on other important chemical reactions involving carboncarbon coupling are underway.

ASSOCIATED CONTENT Materials and experimental methods, and supplementary figures and tables. This material is available free of charge via the Internet at http://pubs.acs.org.

AUTHOR INFORMATION Corresponding Author [email protected]

Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT The work was supported in part by the U.S. Army Research Laboratory and the U.S. Army Research Office under grant W911NF-15-1-0147 on "New Composite Catalysts Based on Nitrogen-Doped Graphene and Nanoparticles for Advanced Electrocatalysis", and by Strem Chemicals. JF thanks the support from the China Scholarship Council. MM is supported by the National

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Science Foundation Graduate Research Fellowship under Grant No. 1644760. Part of electron microscopy work was performed at the Center for Functional Nanomaterials, Brookhaven National Laboratory, supported by the U.S. Department of Energy (DOE), Office of Basic Energy Science, under Contract No. DESC0012704.

REFERENCES (1) Salgado, E. N.; Radford, R. J.; Tezcan, F. A. MetalDirected Protein Self-Assembly. Acc Chem Res 2010, 43, 661-672. (2) Toulemon, D.; Pichon, B. P.; Leuvrey, C.; Zafeiratos, S.; Papaefthimiou, V.; Cattoen, X.; Begin-Colin, S. Fast Assembling of Magnetic Iron Oxide Nanoparticles by Microwave-Assisted Copper(I) Catalyzed Alkyne-Azide Cycloaddition (CuAAC). Chem Mater 2013, 25, 2849-2854. (3) Bau, J. A.; Li, P.; Marenco, A. J.; Trudel, S.; Olsen, B. C.; Luber, E. J.; Buriak, J. M. Nickel/Iron Oxide Nanocrystals with a Nonequilibrium Phase: Controlling Size, Shape, and Composition. Chem Mater 2014, 26, 4796-4804. (4) Besson, M.; Gallezot, P.; Pinel, C. Conversion of Biomass into Chemicals over Metal Catalysts. Chem Rev 2014, 114, 18271870. (5) Li, D. C.; Yun, H.; Diroll, B. T.; Doan-Nguyen, V. V. T.; Kikkawa, J. M.; Murray, C. B. Synthesis and Size-Selective Precipitation of Monodisperse Nonstoichiometric MxFe3-xO4 (M = Mn, Co) Nanocrystals and Their DC and AC Magnetic Properties. Chem Mater 2016, 28, 480-489. (6) Wang, M.; Yin, Y. Magnetically Responsive Nanostructures with Tunable Optical Properties. J Am Chem Soc 2016, 138, 6315-6323. (7) He, D. S.; He, D.; Wang, J.; Lin, Y.; Yin, P.; Hong, X.; Wu, Y.; Li, Y. Ultrathin Icosahedral Pt-Enriched Nanocage with Excellent Oxygen Reduction Reaction Activity. J Am Chem Soc 2016, 138, 1494-1497. (8) Xia, Y. N.; Xia, X. H.; Peng, H. C. Shape-Controlled Synthesis of Colloidal Metal Nanocrystals: Thermodynamic versus Kinetic Products. J Am Chem Soc 2015, 137, 7947-7966. (9) Zhang, S.; Zhang, X.; Jiang, G. M.; Zhu, H. Y.; Guo, S. J.; Su, D.; Lu, G.; Sun, S. H. Tuning Nanoparticle Structure and Surface Strain for Catalysis Optimization. J Am Chem Soc 2014, 136, 77347739. (10) Quan, Z. W.; Xu, H. W.; Wang, C. Y.; Wen, X. D.; Wang, Y. X.; Zhu, J. L.; Li, R. P.; Sheehan, C. J.; Wang, Z. W.; Smilgies, D. M.; Luo, Z. P.; Fang, J. Y. Solvent-Mediated Self-Assembly of Nanocube Superlattices. J Am Chem Soc 2014, 136, 1352-1359. (11) Niu, Z. Q.; Li, Y. D. Removal and Utilization of Capping Agents in Nanocatalysis. Chem Mater 2014, 26, 72-83. (12) McCrory, C. C. L.; Jung, S. H.; Peters, J. C.; Jaramillo, T. F. Benchmarking Heterogeneous Electrocatalysts for the Oxygen Evolution Reaction. J Am Chem Soc 2013, 135, 16977-16987. (13) Tao, F.; Grass, M. E.; Zhang, Y. W.; Butcher, D. R.; Renzas, J. R.; Liu, Z.; Chung, J. Y.; Mun, B. S.; Salmeron, M.; Somorjai, G. A. Reaction-Driven Restructuring of Rh-Pd and Pt-Pd Core-Shell Nanoparticles. Science 2008, 322, 932-934. (14) Yao, Y.; He, D. S.; Lin, Y.; Feng, X.; Wang, X.; Yin, P.; Hong, X.; Zhou, G.; Wu, Y.; Li, Y. Modulating fcc and hcp Ruthenium on the Surface of Palladium-Copper Alloy through Tunable Lattice Mismatch. Angew Chem Int Edit 2016, 55, 55015505. (15) Li, S. W.; Tuel, A.; Laprune, D.; Meunier, F.; Farrusseng, D. Transition-Metal Nanoparticles in Hollow Zeolite Single Crystals as Bifunctional and Size-Selective Hydrogenation Catalysts. Chem Mater 2015, 27, 276-282. (16) Song, W. Q.; Poyraz, A. S.; Meng, Y. T.; Ren, Z.; Chen, S. Y.; Suib, S. L. Mesoporous Co3O4 with Controlled Porosity: Inverse Micelle Synthesis and High-Performance Catalytic CO Oxidation at60 degrees C. Chem Mater 2014, 26, 4629-4639. (17) Yang, H. J.; He, S. Y.; Chen, H. L.; Tuan, H. Y. Monodisperse Copper Nanocubes: Synthesis, Self-Assembly, and Large-Area Dense-Packed Films. Chem Mater 2014, 26, 1785-1793.


Page 5 of 7

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(18) Goncalves, G.; Marques, P. A. A. P.; Granadeiro, C. M.; Nogueira, H. I. S.; Singh, M. K.; Gracio, J. Surface Modification of Graphene Nanosheets with Gold Nanoparticles: The Role of Oxygen Moieties at Graphene Surface on Gold Nucleation and Growth. Chem Mater 2009, 21, 4796-4802. (19) Kou, R.; Shao, Y. Y.; Mei, D. H.; Nie, Z. M.; Wang, D. H.; Wang, C. M.; Viswanathan, V. V.; Park, S.; Aksay, I. A.; Lin, Y. H.; Wang, Y.; Liu, J. Stabilization of Electrocatalytic Metal Nanoparticles at Metal-Metal Oxide-Graphene Triple Junction Points. J Am Chem Soc 2011, 133, 2541-2547. (20) Guo, S. J.; Zhang, S.; Wu, L. H.; Sun, S. H. Co/CoO Nanoparticles Assembled on Graphene for Electrochemical Reduction of Oxygen. Angew Chem Int Edit 2012, 51, 11770-11773. (21) Kozlov, S. M.; Vines, F.; Gorling, A. Bonding Mechanisms of Graphene on Metal Surfaces. J Phys Chem C 2012, 116, 73607366. (22) Yuan, F. W.; Tuan, H. Y. Scalable Solution-Grown HighGermanium-Nanoparticle-Loading Graphene Nanocomposites as High-Performance Lithium-Ion Battery Electrodes: An Example of a Graphene-Based Platform toward Practical Full-Cell Applications. Chem Mater 2014, 26, 2172-2179. (23) Rossin, A.; Peruzzini, M. Ammonia-Borane and AmineBorane Dehydrogenation Mediated by Complex Metal Hydrides. Chem Rev 2016, 116, 8848–8872. (24) Goksu, H.; Ho, S. F.; Metin, O.; Korkmaz, K.; Garcia, A. M.; Gultekin, M. S.; Sun, S. H. Tandem Dehydrogenation of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds Catalyzed by Graphene-Supported NiPd Alloy Nanoparticles. Acs Catal 2014, 4, 1777-1782. (25) Metin, O.; Mazumder, V.; Ozkar, S.; Sun, S. S. Monodisperse Nickel Nanoparticles; and Their Catalysis in Hydrolytic Dehydrogenation of Ammonia Borane. J Am Chem Soc 2010, 132, 1468-1469. (26) Koepke, J. C.; Wood, J. D.; Chen, Y. F.; Schmucker, S. W.; Liu, X. M.; Chang, N. N.; Nienhaus, L.; Do, J. W.; Carrion, E. A.; Hewaparakrama, J.; Ranaarajan, A.; Datye, I.; Mehta, R.; Haasch, R. T.; Gruebele, M.; Girolami, G. S.; Pop, E.; Lyding, J. W. Role of Pressure in the Growth of Hexagonal Boron Nitride Thin Films from Ammonia-Borane. Chem Mater 2016, 28, 4169-4179. (27) Ryschkewitsch, G. E. Amine Boranes .1. Kinetics of Acid Hydrolysis of Trimethylamine Borane. J Am Chem Soc 1960, 82, 3290-3294. (28) Hu, M. G.; Geanangel, R. A.; Wendlandt, W. W. ThermalDecomposition of Ammonia-Borane. Thermochim Acta 1978, 23, 249-255. (29) Brown, H. C.; Chandrasekharan, J. Mechanism of Hydroboration of Alkenes with Borane-Lewis Base Complexes Evidence That the Mechanism of the Hydroboration Reaction Proceeds through a Prior Dissociation of Such Complexes. J Am Chem Soc 1984, 106, 1863-1865. (30) Wolf, G.; Baumann, J.; Baitalow, F.; Hoffmann, F. P. Calorimetric process monitoring of thermal decomposition of B-N-H compounds. Thermochim Acta 2000, 343, 19-25. (31) Gutowska, A.; Li, L. Y.; Shin, Y. S.; Wang, C. M. M.; Li, X. H. S.; Linehan, J. C.; Smith, R. S.; Kay, B. D.; Schmid, B.; Shaw, W.; Gutowski, M.; Autrey, T. Nanoscaffold mediates hydrogen release and the reactivity of ammonia borane. Angew Chem Int Edit 2005, 44, 3578-3582. (32) Zhang, J. G.; Teo, J.; Chen, X.; Asakura, H.; Tanaka, T.; Teramura, K.; Yan, N. A Series of NiM (M = Ru, Rh, and Pd) Bimetallic Catalysts for Effective Lignin Hydrogenolysis in Water. Acs Catal 2014, 4, 1574-1583. (33) Shang, L.; Bian, T.; Zhang, B. H.; Zhang, D. H.; Wu, L. Z.; Tung, C. H.; Yin, Y. D.; Zhang, T. R. Graphene-Supported Ultrafine Metal Nanoparticles Encapsulated by Mesoporous Silica: Robust Catalysts for Oxidation and Reduction Reactions. Angew Chem Int Edit 2014, 53, 250-254. (34) Zhang, H.; Jin, M. S.; Xiong, Y. J.; Lim, B.; Xia, Y. N. Shape-Controlled Synthesis of Pd Nanocrystals and Their Catalytic Applications. Acc Chem Res 2013, 46, 1783-1794.

(35) Peng, C. Y.; Kang, L.; Cao, S.; Chen, Y.; Lin, Z. S.; Fu, W. F. Nanostructured Ni2P as a Robust Catalyst for the Hydrolytic Dehydrogenation of Ammonia-Borane. Angew Chem Int Edit 2015, 54, 15725-15729. (36) Alonso, F.; Moglie, Y.; Radivoy, G. Copper Nanoparticles in Click Chemistry. Acc Chem Res 2015, 48, 2516-2528. (37) Liao, L. B.; Zhang, Q. H.; Su, Z. H.; Zhao, Z. Z.; Wang, Y. N.; Li, Y.; Lu, X. X.; Wei, D. G.; Feng, G. Y.; Yu, Q. K.; Cai, X. J.; Zhao, J. M.; Ren, Z. F.; Fang, H.; Robles-Hernandez, F.; Baldelli, S.; Bao, J. M. Efficient solar water-splitting using a nanocrystalline CoO photocatalyst. Nat Nanotechnol 2014, 9, 69-73. (38) He, C. N.; Wu, S.; Zhao, N. Q.; Shi, C. S.; Liu, E. Z.; Li, J. J. Carbon-Encapsulated Fe3O4 Nanoparticles as a High-Rate Lithium Ion Battery Anode Material. Acs Nano 2013, 7, 4459-4469. (39) Goksu, H.; Can, H.; Sendil, K.; Gultekin, M. S.; Metin, O. CoPd alloy nanoparticles catalyzed tandem ammonia borane dehydrogenation and reduction of aromatic nitro, nitrile and carbonyl compounds. Appl Catal a-Gen 2014, 488, 176-182. (40) Metin, O.; Mendoza-Garcia, A.; Dalmizrak, D.; Gultekin, M. S.; Sun, S. H. FePd alloy nanoparticles assembled on reduced graphene oxide as a catalyst for selective transfer hydrogenation of nitroarenes to anilines using ammonia borane as a hydrogen source. Catal Sci Technol 2016, 6, 6137-6143. (41) Metin, O.; Ho, S. F.; Alp, C.; Can, H.; Mankin, M. N.; Gultekin, M. S.; Chi, M. F.; Sun, S. H. Ni/Pd core/shell nanoparticles supported on graphene as a highly active and reusable catalyst for Suzuki-Miyaura cross-coupling reaction. Nano Res 2013, 6, 10-18. (42) Diyarbakir, S.; Can, H.; Metin, O. Reduced Graphene Oxide-Supported CuPd Alloy Nanoparticles as Efficient Catalysts for the Sonogashira Cross-Coupling Reactions. Acs Appl Mater Inter 2015, 7, 3199-3206. (43) Xiao, Q.; Sarina, S.; Waclawik, E. R.; Jia, J. F.; Chang, J.; Riches, J. D.; Wu, H. S.; Zheng, Z. F.; Zhu, H. Y. Alloying Gold with Copper Makes for a Highly Selective Visible-Light Photocatalyst for the Reduction of Nitroaromatics to Anilines. Acs Catal 2016, 6, 17441753. (44) Aditya, T.; Pal, A.; Pal, T. Nitroarene reduction: a trusted model reaction to test nanoparticle catalysts. Chem Commun 2015, 51, 9410-9431. (45) Westerhaus, F. A.; Jagadeesh, R. V.; Wienhofer, G.; Pohl, M. M.; Radnik, J.; Surkus, A. E.; Rabeah, J.; Junge, K.; Junge, H.; Nielsen, M.; Bruckner, A.; Beller, M. Heterogenized cobalt oxide catalysts for nitroarene reduction by pyrolysis of molecularly defined complexes. Nat Chem 2013, 5, 537-543. (46) Jagadeesh, R. V.; Surkus, A. E.; Junge, H.; Pohl, M. M.; Radnik, J.; Rabeah, J.; Huan, H. M.; Schunemann, V.; Bruckner, A.; Beller, M. Nanoscale Fe2O3-Based Catalysts for Selective Hydrogenation of Nitroarenes to Anilines. Science 2013, 342, 10731076. (47) Panigrahi, S.; Basu, S.; Praharaj, S.; Pande, S.; Jana, S.; Pal, A.; Ghosh, S. K.; Pal, T. Synthesis and size-selective catalysis by supported gold nanoparticles: Study on heterogeneous and homogeneous catalytic process. J Phys Chem C 2007, 111, 45964605. (48) Naresh, N.; Wasim, F. G. S.; Ladewig, B. P.; Neergat, M. Removal of surfactant and capping agent from Pd nanocubes (PdNCs) using tert-butylamine: its effect on electrochemical characteristics. J Mater Chem A 2013, 1, 8553-8559. (49) Wu, J. B.; Zhang, J. L.; Peng, Z. M.; Yang, S. C.; Wagner, F. T.; Yang, H. Truncated Octahedral Pt3Ni Oxygen Reduction Reaction Electrocatalysts. J Am Chem Soc 2010, 132, 4984-4985. (50) Metin, O.; Duman, S.; Dinc, M.; Ozkar, S. OleylamineStabilized Palladium(0) Nanoclusters As Highly Active Heterogeneous Catalyst for the Dehydrogenation of Ammonia Borane. J Phys Chem C 2011, 115, 10736-10743. (51) Sun, D. H.; Mazumder, V.; Metin, O.; Sun, S. H. Methanolysis of Ammonia Borane by CoPd Nanoparticles. Acs Catal 2012, 2, 1290-1295. (52) Yao, Q. L.; Huang, M.; Lu, Z. H.; Yang, Y. W.; Zhang, Y. X.; Chen, X. S.; Yang, Z. Methanolysis of ammonia borane by shape-



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

controlled mesoporous copper nanostructures for hydrogen generation. Dalton T 2015, 44, 1070-1076. (53) Acerbi, N.; Tsang, S. C. E.; Jones, G.; Golunski, S.; Collier, P. Rationalization of Interactions in Precious Metal/Ceria Catalysts Using the d-Band Center Model. Angew Chem Int Edit 2013, 52, 7737-7741. (54) Bruix, A.; Rodriguez, J. A.; Ramirez, P. J.; Senanayake, S. D.; Evans, J.; Park, J. B.; Stacchiola, D.; Liu, P.; Hrbek, J.; Illas, F. A New Type of Strong Metal-Support Interaction and the Production of H2 through the Transformation of Water on Pt/CeO2(111) and Pt/CeOx/TiO2(110) Catalysts. J Am Chem Soc 2012, 134, 8968-8974. (55) Nilsson, A.; Pettersson, L. G. M.; Nørskov, J. K.: Chemical bonding at surfaces and interfaces; 1st ed.; Elsevier: Amsterdam ; Boston Mass., 2008. (56) Wu, C. T.; Qu, J.; Elliott, J.; Yu, K. M. K.; Tsang, S. C. E. Hydrogenolysis of ethylene glycol to methanol over modified RANEY (R) catalysts. Phys Chem Chem Phys 2013, 15, 9043-9050. (57) Studt, F.; Abild-Pedersen, F.; Bligaard, T.; Sorensen, R. Z.; Christensen, C. H.; Norskov, J. K. Identification of non-precious metal alloy catalysts for selective hydrogenation of acetylene. Science 2008, 320, 1320-1322. (58) Erdogan, H.; Metin, O.; Ozkar, S. In situ-generated PVPstabilized palladium(0) nanocluster catalyst in hydrogen generation from the methanolysis of ammonia-borane. Phys Chem Chem Phys 2009, 11, 10519-10525. (59) Yao, Q. L.; Lu, Z. H.; Yang, K. K.; Chen, X. S.; Zhu, M. H. Ruthenium nanoparticles confined in SBA-15 as highly efficient catalyst for hydrolytic dehydrogenation of ammonia borane and hydrazine borane. Sci Rep-Uk 2015, 5, DOI:10.1038/srep15186. (60) Dai, H. B.; Kang, X. D.; Wang, P. Ruthenium nanoparticles immobilized in montmorillonite used as catalyst for methanolysis of ammonia borane. Int J Hydrogen Energ 2010, 35, 10317-10323. (61) Zhou, L. M.; Zhang, T. R.; Tao, Z. L.; Chen, J. Ni nanoparticles supported on carbon as efficient catalysts for the hydrolysis of ammonia borane. Nano Res 2014, 7, 774-781. (62) Li, P. Y.; Xiao, Z. L.; Liu, Z. Y.; Huang, J. L.; Li, Q. B.; Sun, D. H. Highly efficient hydrogen generation from methanolysis of ammonia borane on CuPd alloy nanoparticles. Nanotechnology 2015, 26, DOI: 10.1088/0957-4484/26/2/025401 (63) Amali, A. J.; Aranishi, K.; Uchida, T.; Xu, Q. PdPt Nanocubes: A High-Performance Catalyst for Hydrolytic Dehydrogenation of Ammonia Borane. Part Part Syst Char 2013, 30, 888-892. (64) Akbayrak, S.; Erdek, P.; Ozkar, S. Hydroxyapatite supported ruthenium(0) nanoparticles catalyst in hydrolytic dehydrogenation of ammonia borane: Insight to the nanoparticles formation and hydrogen evolution kinetics. Appl Catal B-Environ 2013, 142, 187-195. (65) Chen, Y. Z.; Xu, Q.; Yu, S. H.; Jiang, H. L. Tiny Pd@Co Core-Shell Nanoparticles Confined inside a Metal-Organic Framework for Highly Efficient Catalysis. Small 2015, 11, 71-76. (66) Yurderi, M.; Bulut, A.; Zahmakiran, M.; Kaya, M. Carbon supported trimetallic PdNiAg nanoparticles as highly active, selective and reusable catalyst in the formic acid decomposition. Appl Catal BEnviron 2014, 160, 514-524. (67) Metin, O.; Sun, X. L.; Sun, S. H. Monodisperse goldpalladium alloy nanoparticles and their composition-controlled catalysis in formic acid dehydrogenation under mild conditions. Nanoscale 2013, 5, 910-912.


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