Hydrolytic Dehydrogenation Research Articles

Carbon-supported Ni3B nanoparticles as catalysts for hydrogen generation from hydrolysis of ammonia borane

We report the preparation of Ni3B and carbon-supported Ni3B (denoted as Ni3B/C) nanoparticles, and their catalytic performance for hydrogen generation from hydrolytic dehydrogenation of ammonia borane (NH3BH3, AB). Ni3B and Ni3B/C were prepared via a chemical reduction and crystallization in tetraethylene glycol solution. The obtained Ni3B catalysts are in well-defined crystalline state and Ni3B/C catalysts have a high dispersion in the carbon. The hydrogen generation measurement shows that the carbon-supported Ni3B presents enhanced catalyst activity during hydrolytic dehydrogenation of AB. Among the as-prepared Ni3B/C catalysts, Ni3B/C with 34.25 wt% Ni3B loading displays the best catalytic activity, delivering a high hydrogen release rate of 1168 mL min−1 g−1 and the lower activation energy of 46.27 kJ mol−1. The kinetic results show that the hydrolysis is a first-order reaction in catalyst concentration, while it is a zero-order in AB concentration. Furthermore, the Ni3B/C is a recyclable catalyst under mild reaction conditions, indicating that the carbon-supported Ni3B is a promising catalyst for AB hydrolytic dehydrogenation.

Electrospun CdS–TiO2 doped carbon nanofibers for visible-light-induced photocatalytic hydrolysis of ammonia borane

CdS/TiO2 NPs-decorated carbon nanofibers were introduced as a novel photocatalyst working under visible light radiation for the effective hydrolytic dehydrogenation of ammonia borane. Calcination of electrospun nanofiber mats composed of titanium tetraisopropoxide, poly (vinyl pyrrolidone) (PVP), and cadmium acetate dihydrate with a few drops of ammonium sulfide in argon atmosphere at 850°C led to the production of CdS–TiO2 decorated carbon nanofibers. As-synthesized nanocomposite exhibited a strong photocatalytic activity for catalytic hydrolysis of ammonia–borane. The favorable electrons-transfer properties, better dispersion, high surface area, and adsorption property are the main features of nanocomposites that exhibit high catalytic efficiency.

Ultrafine Ru nanoparticles embedded in SiO2 nanospheres: Highly efficient catalysts for hydrolytic dehydrogenation of ammonia borane

Ru@SiO2 core–shell structured nanospheres have been prepared via a one-pot synthetic route in a NP-5/cyclohexane reverse micelle system and characterized by XRD, SEM, TEM, N2 adsorption–desorption, and H2 temperature programmed desorption. The characterized results show that ultrafine Ru nanoparticles (NPs) of around 2 nm are effectively embedded in the center of well-proportioned spherical and porous silica nanospheres (∼25 nm in diameter). Interestingly, the number of Ru NPs increases inside the spherical particles of SiO2 as the increase of Ru loading. The as-synthesized Ru@SiO2 exhibits high catalytic activity and good durability for hydrogen generation from the aqueous of ammonia borane (AB) complex under ambient atmosphere at room temperature. The hydrolysis activation energy of Ru@SiO2 was estimated to be about 38.2 kJ mol−1, which is lower than most of the reported activation energy values for the same reaction using many different Ru-based and other noble metal containing catalysts, indicating the superior catalytic performance of these core–shell structured nanospheres.

Influence of preparation conditions of hollow titania–nickel composite spheres on their catalytic activity for hydrolytic dehydrogenation of ammonia borane

The present work reports influence of preparation conditions of hollow titania–nickel composite spheres on their morphology and catalytic activity for hydrolytic dehydrogenation of ammonia borane (NH3BH3). The as-prepared hollow titania–nickel composite spheres were characterized by transmission electron microscopy (TEM). Catalytic activities of the hollow spheres for hydrolytic dehydrogenation of aqueous NaBH4/NH3BH3 solution improve with the decrease of Ti+Ni content. From the results of FTIR spectra and elemental analysis, the amount of residual polystyrene (PS) templates is able to be reduced by increasing aging time for the preparation, and the catalytic activity of the hollow spheres increases when the amount of residual PS templates decreases. The carbon content in the hollow spheres prepared with aging time=24h is 17.3wt.%, and the evolution of 62mL hydrogen is finished in about 22min in the presence of the hollow spheres from aqueous NaBH4/NH3BH3 solution. The molar ratio of the hydrolytically generated hydrogen to the initial NH3BH3 in the presence of the hollow spheres is 2.7.

In situ facile synthesis of bimetallic CoNi catalyst supported on graphene for hydrolytic dehydrogenation of amine borane

Well dispersed magnetically recyclable bimetallic CoxNi1−x (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) nanoparticles (NPs) supported on graphene have been synthesized via a facile in situ one-step procedure, using the mixture of sodium borohydride (NaBH4) and methylamine borane (MeAB) as the reducing agent under ambient condition. These NPs were composition dependent for catalytic hydrolysis of amine boranes. Among all the CoNi/graphene catalysts tested, the Co0.9Ni0.1/graphene NPs exhibit the highest catalytic activity toward hydrolysis of AB with the turnover frequency (TOF) value of 16.4 (mol H2 min−1 (mol catalyst)−1), being higher than that of most reported non-noble metal-based NPs, and even many noble metal-based NPs. Moreover, the activation energy (Ea) value is 13.49 kJ/mol, which is the second lowest value ever reported for catalytic hydrolytic dehydrogenation of ammonia borane, indicating the superior catalytic performance of the as-synthesized Co0.9Ni0.1/graphene catalysts. Additionally, Compared with other reducing agents, such as NaBH4, AB, MeAB, and the mixture of NaBH4 and AB, the as-synthesized Co0.9Ni0.1/graphene catalysts reduced by the mixture of NaBH4 and MeAB exert the highest catalytic activity. The Co0.9Ni0.1 NPs supported on graphene exhibit higher catalytic activity than catalysts with other conventional supports, such as SiO2, carbon black, and γ-Al2O3. Furthermore, the as-synthesized Co0.9Ni0.1/graphene NPs show good recyclability and magnetically reusability for the hydrolytic dehydrogenation of amine boranes, which make the practical reusing application of the catalysts more convenient.

Strategic synthesis of graphene supported trimetallic Ag-based core–shell nanoparticles toward hydrolytic dehydrogenation of amine boranes

We reported the synthesis and characterization of two trimetallic (Ag@CoFe, and Ag@NiFe) core–shell nanoparticles (NPs), and their catalytic activity toward hydrolytic dehydrogenation of ammonia borane (AB) and methylamine borane (MeAB). The as-synthesized trimetallic core–shell NPs were obtained via a facile one-step in situ procedure using methylamine borane as a reducing agent and graphene as the support under ambient condition. The as-synthesized NPs are well dispersed on graphene, and exhibit higher catalytic activity than the catalysts with other conventional supports, such as the SiO2, carbon black, and γ-Al2O3. Additionally, compared with NaBH4 and AB, the as-synthesized Ag@CoFe/graphene NPs reduced by MeAB exhibit the highest catalytic activity, with the turnover frequency (TOF) value of 82.9 (mol H2 min−1 (mol Ag)−1), and the activation energy (Ea) value of 32.79 kJ/mol. Furthermore, the as-prepared NPs exert good durable and magnetically recyclability for the hydrolytic dehydrogenation of AB and MeAB. Moreover, this simple strategic synthesis method can be easily extended to the facile preparation of other graphene supported multi-metal core–shell NPs.

Nickel nanoparticles immobilized on three-dimensional nitrogen-doped graphene as a superb catalyst for the generation of hydrogen from the hydrolysis of ammonia borane

Nickel nanoparticles immobilized on three-dimensional nitrogen-doped graphene-based frameworks (NiNPs@3D-(N)GFs) were synthesized and examined for hydrogen generation from the hydrolytic dehydrogenation of ammonia borane.

Influence of Preparation Conditions on Morphology of in-situ Synthesized Hollow Nickel-silica Spheres for Hydrolytic Dehydrogenation of Ammonia Borane

Influence of Preparation Conditions on Morphology of in-situ Synthesized Hollow Nickel-silica Spheres for Hydrolytic Dehydrogenation of Ammonia Borane

Catalytic Hydrolysis of Ammonia Borane by Cobalt Nickel Nanoparticles Supported on Reduced Graphene Oxide for Hydrogen Generation

Well dispersed magnetically recyclable bimetallic CoNi nanoparticles (NPs) supported on the reduced graphene oxide (RGO) were synthesized by one‐step in situ coreduction of aqueous solution of cobalt(II) chloride, nickel (II) chloride, and graphite oxide (GO) with ammonia borane (AB) as the reducing agent under ambient condition. The CoNi/RGO NPs exhibits excellent catalytic activity with a total turnover frequency (TOF) value of 19.54 mol H2 mol catalyst−1 min−1 and a low activation energy value of 39.89 kJ mol−1 at room temperature. Additionally, the RGO supported CoNi NPs exhibit much higher catalytic activity than the monometallic and RGO‐free CoNi counterparts. Moreover, the as‐prepared catalysts exert satisfying durable stability and magnetically recyclability for the hydrolytic dehydrogenation of AB, which make the practical reusing application of the catalysts more convenient. The usage of the low‐cost, easy‐getting catalyst to realize the production of hydrogen under mild condition gives more confidence for the application of ammonia borane as a hydrogen storage material. Hence, this general method indicates that AB can be used as both a potential hydrogen storage material and an efficient reducing agent, and can be easily extended to facile preparation of other RGO‐based metallic systems.

Ruthenium(0) nanoparticles supported on xonotlite nanowire: a long-lived catalyst for hydrolytic dehydrogenation of ammonia-borane

Ruthenium(0) nanoparticles supported on xonotlite nanowire (Ru(0)@X-NW) were prepared by the ion exchange of Ru(3+) ions with Ca(2+) ions in the lattice of xonotlite nanowire followed by their reduction with sodium borohydride in aqueous solution at room temperature. Ru(0)@X-NW were characterized by a combination of advanced analytical techniques. The results show that (i) highly dispersed ruthenium(0) nanoparticles of 4.4 ± 0.4 nm size were formed on the surface of xonotlite nanowire, (ii) Ru(0)@X-NW show high catalytic activity in hydrogen generation from the hydrolytic dehydrogenation of ammonia borane with a turnover frequency value up to 135 min(-1) at 25.0 ± 0.1 °C. (iii) They provide unprecedented catalytic life time (TTO = 134,100) for hydrogen generation from the hydrolysis of ammonia borane at 25.0 ± 0.1 °C. (iv) The results of a kinetic study on the hydrogen generation from the hydrolysis of ammonia borane were also reported including the activation energy of 77 ± 2 kJ mol(-1) for this reaction.

Facile in situ synthesis of copper nanoparticles supported on reduced graphene oxide for hydrolytic dehydrogenation of ammonia borane

A facile in situ procedure has been successfully applied for synthesis of a RGO/Cu nanocomposite, which leads to the highest catalytic activity of Cu nanocatalysts up to now for the dehydrogenation of ammonia borane.

Unique reactivity in Pt/CNT catalyzed hydrolytic dehydrogenation of ammonia borane

We demonstrate an unprecedented H2 generation activity in the hydrolytic dehydrogenation of ammonia borane over acid oxidation- and subsequent high temperature-treated CNT immobilized Pt nanocatalysts to combine the merits of defect-rich and oxygen group-deficient surfaces and unique textural properties of supports as well as optimum particle size of Pt.

Effect of Solvents on Morphology of Hollow Nickel-Silica Composite Spheres and Their Catalytic Performance for Hydrolytic Dehydrogenation of Ammonia Borane

We study the effect of solvents on morphological and/or structural properties and catalytic activity of hollow nickel-silica composite spheres for hydrolytic dehydrogenation of ammonia borane. Nickel-silica composite shells were coated on polystyrene (PS) templates via sol-gel reaction with L(+)-arginine as the promoter of the sol-gel reaction followed or in parallel with the dissolution of the PS templates in the same medium to form hollow spheres. From the transmission electron microscopy (TEM) images, nickel-silica composite shells were formed for 1.5 h, and the surface roughness of the shells increases with the increase of aging time in methyl alcohol, while the shells were formed via the formation of aggregates of irregular shape in ethyl alcohol and 2-propyl alcohol. From the angle attenuated total reflectance infrared (ATR-IR) spectra, the order of dissolution rate of PS templates is 2-propyl alcohol > ethyl alcohol > methyl alcohol. These results indicate that the shells are formed before the dissolution of PS templates in methyl alcohol, while in ethyl alcohol and 2-propyl alcohol, nickel-silica composite shells was formed in parallel with dissolution of PS templates via the formation of aggregates of irregular shape. From the results of N

Control of Particle Size of Hollow Silica-alumina Composite Spheres and Their Activity for Hydrolytic Dehydrogenation of Ammonia Borane

The influence of particle size of hollow silica-alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane (NH3BH3) was investigated. A silica-alumina composite shell was coated onto polystyrene (PS) template particles, before the removal of PS template particle by calcination. The diameter of the PS template particles decreased with an increase in the amount of poly (vinyl pyrrolidone) and the centrifugation speed, and the diameter of the obtained PS template particles was controlled between 150 and 400 nm. Hollow silica-alumina composite spheres with diameters of 180, 230, and 430 nm were prepared using these PS template particles; the shell thickness was controlled 15 nm by adjusting the amount of PS suspension and coating time. The hydrolytic dehydrogenation of NH3BH3 evolved 9.5, 9.0, and 7.0 mL hydrogen in the presence of hollow spheres with diameters of 180, 230, and 430 nm, respectively; the molar ratios of the generated hydrogen to the initial NH3BH3 in the presence of the hollow spheres were 2.5, 2.3, and 1.8, respectively. The results indicate that the activity increases with a decrease in the diameter of hollow spheres.

Core-shell structured nanospheres with mesoporous silica shell and Ni core as a stable catalyst for hydrolytic dehydrogenation of ammonia borane

Core-shell structured nanospheres with mesoporous silica shell and Ni core (denoted as Ni@meso-SiO2) are prepared through a three-step process. Monodispersed Ni precursors are first prepared, and then coated with mesoporous SiO2. Final Ni@meso-SiO2 spheres are obtained after calcination. The products are characterized by X-ray powder diffraction, transmission electron microscopy and N2 adsorption-desorption methods. These spheres have a high surface area and are well dispersed in water, showing a high catalytic activity with a TOF value of 18.5, and outstanding stability in hydrolytic dehydrogenation of ammonia borane at room temperature.

Highly active AuCo alloy nanoparticles encapsulated in the pores of metal-organic frameworks for hydrolytic dehydrogenation of ammonia borane.

Ultrafine AuCo alloy nanoparticles were successfully encapsulated in the pores of MIL-101 by using the double solvents method combined with the overwhelming reduction approach, which exert excellent catalytic activity for hydrolytic dehydrogenation of ammonia borane.

Nanocatalysts for Hydrogen Generation from Ammonia Borane and Hydrazine Borane

Ammonia borane (denoted as AB, NH3BH3) and hydrazine borane (denoted as HB, N2H4BH3), having hydrogen content as high as 19.6 wt% and 15.4 wt%, respectively, have been considered as promising hydrogen storage materials. Particularly, the AB and HB hydrolytic dehydrogenation system can ideally release 7.8 wt% and 12.2 wt% hydrogen of the starting materials, respectively, showing their high potential for chemical hydrogen storage. A variety of nanocatalysts have been prepared for catalytic dehydrogenation from aqueous or methanolic solution of AB and HB. In this review, we survey the research progresses in nanocatalysts for hydrogen generation from the hydrolysis or methanolysis of NH3BH3 and N2H4BH3.

RuCu nanoparticles supported on graphene: A highly efficient catalyst for hydrolysis of ammonia borane

Well dispersed RuCu nanoparticles (NPs) supported on graphene were in situ synthesized by a one-step co-reduction of aqueous solution of ruthenium (III) chloride, cupric (II) chloride, and graphite oxide (GO) with ammonia borane (AB) under ambient condition. The nature of the NPs was fully characterized by TEM, HRTEM, XRD, energy dispersive spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The as-synthesized NPs exhibit much higher catalytic activity for hydrolytic dehydrogenation of AB than the monometallic Ru and Cu, bimetallic RuCu/graphene reduced by NaBH4, and graphene free RuCu counterparts. Additionally, the as-synthesized NPs supported on graphene exhibit higher catalytic activity than the catalysts with other conventional supports, such as SiO2, γ-Al2O3, and carbon black. The activity of Ru1Cu7.5/graphene NPs in terms of turnover frequency (TOF) is 135mol H2min−1 (mol Ru)−1, which is higher than Ru/graphene, and most reported Ru-based or other noble metal-based NPs for the catalytic hydrolysis of AB. The activation energy for hydrolysis of AB in the presence of Ru1Cu7.5/graphene NPs was determined as 30.59kJmol−1, which is lower than most of the reported catalysts. Furthermore, the as-prepared NPs exert satisfied durable stability for the hydrolytic dehydrogenation of AB.

Influence of preparation conditions of hollow silica–nickel composite spheres on their catalytic activity for hydrolytic dehydrogenation of ammonia borane

In this paper, we investigated influence of preparation conditions of hollow silica–nickel composite spheres on their morphology and catalytic activity for hydrolytic dehydrogenation of ammonia borane. In the preparation method of this study, when silica–nickel composite shells were coated on polystyrene templates by the sol–gel method using L(+)-arginine as the promoter for the reaction to form silica–nickel composite shell, the polystyrene templates were dissolved subsequently, even synchronously, in the same medium to form hollow spheres. The as-prepared silica–nickel composite spheres were characterized by transmission electron microscopy and scanning electron microscopy. The effects of Si+Ni content on the morphology were systematically evaluated. All the as-prepared hollow silica–nickel composite spheres have the similar morphology as identified by SEM and TEM measurement. Homogeneity of the hollow silica–nickel composite spheres increases with the increase in the Si+Ni content as shown by the laser diffraction particle size analysis. The catalytic activities of the hollow silica–nickel composite spheres for hydrolytic dehydrogenation of ammonia borane prepared with different Si+Ni contents were compared. The catalytic activity for the hydrogen evolution in the presence of the hollow spheres increases with the increase of Si+Ni content. The results of FTIR spectra of the hollow silica–nickel composite spheres indicate that a certain amount of residual PS templates exists in hollow silica–nickel composite spheres. The residual PS templates was able to be reduced by procedure of as-prepared samples with toluene solvent. The catalytic activity of hollow silica–nickel composite spheres increases with decrease in the amount of residual PS templates.

Graphene-Supported Trimetallic Core-Shell Cu@CoNi Nanoparticles for Catalytic Hydrolysis of Amine Borane.

Trimetallic core-shell Cu@CoNi nanoparticles (NPs) supported on graphene with different compositions are synthesized through a one-step in situ reduction process by using methylamine borane (MeAB) as a reducing agent. The as-synthesized Cu-core/CoNi-shell NPs are well dispersed on graphene. Among the catalysts studied, Cu0.1 @Co0.45 Ni0.45 /graphene displays the highest catalytic performance toward the hydrolysis of ammonia borane (AB), with a turnover frequency (TOF) value of 15.46 mol H2 min-1 (mol catalyst)-1 , which is higher than those of most reported non-noble-metal-based NPs, and even higher than many noble-metal-based NPs. Additionally, the as-synthesized Cu0.1 @Co0.45 Ni0.45 /graphene NPs reduced by MeAB exhibit a higher catalytic activity than those reduced by NaBH4 and AB. Furthermore, the as-prepared NPs have good durability and magnetic recyclability for the hydrolytic dehydrogenation of AB and MeAB.