Hydrolytic Dehydrogenation Research Articles

Stratified nanoporous PtTi alloys for hydrolysis of ammonia borane

Stratified nanoporous PtTi (SNP-PtTi) alloys with bimodal size distributions and different components are successfully prepared by selectively dissolving Al atoms followed by removing part of Ti atoms from the PtTiAl precursor alloy. The as-made PtTi alloys have stratified nanoporous architecture with the first order ligaments around 50nm and the second order smaller ligaments around 6nm. The SNP-PtTi alloys with different bimetallic ratios exhibit much higher catalytic activity for the hydrolysis of ammonia borane than NP-Pt catalyst. The SNP-Pt65Ti35 alloy shows superior specific activity toward the hydrolytic dehydrogenation of ammonia borane compared with SNP-Pt50Ti50 and -Pt80Ti20, showing an initial turnover frequency of 51.4mol H2 (molPt)−1min−1. The activation energy of SNP-Pt65Ti35 was estimated to be about 39.4kJmol−1, which was small compared with most of the reported activation energy values in the literature. In addition, the recyclability tests indicate that the SNP-Pt65Ti35 retained 63% of the initial catalytic activity after the fifth run of hydrolysis. The lifetime of SNP-Pt65Ti35 was measured as 16,380 turnovers over 100h in the hydrolysis of ammonia borane before deactivation. The SNP-PtTi alloys show potential application prospect in the field of online hydrogen production due to the high catalytic performance and the facile preparation.

Microporous Crystalline γ-Al2 O3 Replicated from Microporous Covalent Triazine Framework and Its Application as Support for Catalytic Hydrolysis of Ammonia Borane.

Significant progress has been made on the synthesis and application of mesoporous γ-alumina. To date, little attention has been paid to the synthesis of microporous crystalline alumina. Here, fabrication of microporous crystalline γ-alumina using a microporous covalent triazine framework (CTF-1) as a template is described. Microporous crystalline γ-alumina with a micro-meso binary pore system was replicated by infiltration of aluminum nitrate into the micropores of the CTF-1 template through a NH3 /water-vapor-induced internal hydrolysis method, followed by thermal treatment, and subsequent removal of the CTF-1 template with a 30 % H2 O2 aqueous solution. The obtained crystalline γ-alumina material exhibits a large surface area (349 m2 g-1 ) with micropore distribution centered at about 1.27 nm. Ru supported on microporous γ-Al2 O3 can be employed as catalyst for hydrolytic dehydrogenation of ammonia borane, and it exhibits high catalytic activity and good durability. This finding provides a new benchmark for preparing well-defined crystalline microporous alumina materials by a template method, which can be applied in a wide range of fields.

Graphene Supported RuNi Alloy Nanoparticles as Highly Efficient and Durable Catalyst for Hydrolytic Dehydrogenation‐Hydrogenation Reactions

AbstractHere, reduced graphene oxide (RGO) supported surfactant free, RuNi alloy nanoparticles with particle size <5 nm were synthesized by chemical coreduction route. The synthesized sample was well characterized by various techniques and showed complete solid solution without any extra phase, where Ru lattice is required for nucleation of metallic Ni. The RuxNi100‐x /RGO (x=100, 75, 50 and 25) nanocomposites (NCs) exhibits remarkable activity in hydrolytic dehydrogenation of NH3BH3 (ammonia borane, AB). Among various RuxNi100‐x compositions, Ru50Ni50 NPs showed best performance with maximum H2 evolution rate 9305.6 mL min−1 g−1 and TOF value 236 min−1 at 30 oC, which is one of the best value reported till date. In addition, present activity retained upto 7th catalytic cycles, showing high durability which makes it a potential candidate for development of NH3BH3 as a H2 storage material. Moreover, alloy NCs further explored in tandem reduction of nitro and nitrile compounds in presence of AB as H2 source which again showed best performance with excellent yield (>99 %) of amine product with short time period of 4.5‐10 min. Additionally, NCs exhibits high chemoselectivity and durability towards such organic transformation reactions. This high catalytic efficiency of RGO supported RuNi NPs could be ascribed to synergistic interaction between Ru/Ni metals, high surface area (small sized NPs and graphene sheets), RGO as a support material which prevent agglomeration of particle.

Synthesized polyvidone-stabilized Rh(0) nanoparticles catalyzed the hydrolytic dehydrogenation of methylamine-borane in ambient conditions

Polyvidone (PVP40)-stabilized Rh nanoparticles (Rh@PVP40) were synthesized via a classical alcohol reduction technique and were characterized by carrying out TEM, HR-TEM, TEM/EDX, P-XRD analysis, UV/Vis and XPS spectroscopy investigations.

Ternary Ni–Co–P nanoparticles as noble-metal-free catalysts to boost the hydrolytic dehydrogenation of ammonia-borane

Ternary Ni–Co–P nanoparticles with optimized electronic structures strongly interact with ammonia-borane, resulting in the marked improvement of catalytic activity.

Correction: Fabrication of hollow silica–nickel particles for the hydrolytic dehydrogenation of ammonia borane using rape pollen templates

Correction for ‘Fabrication of hollow silica–nickel particles for the hydrolytic dehydrogenation of ammonia borane using rape pollen templates’ by Tetsuo Umegaki et al., New J. Chem., 2017, DOI: 10.1039/c6nj03457h.

MnCo2O4film composed of nanoplates: synthesis, characterization and its superior catalytic performance in the hydrolytic dehydrogenation of ammonia borane

MnCo2O4film composed of nanoplates as an active and reusable catalyst towards the hydrolysis of ammonia borane for hydrogen production.

The influence of the pore structure of hollow silica–alumina composite spheres on their activity for hydrolytic dehydrogenation of ammonia borane

Hollow silica–alumina composite spheres with a homogeneous pore structure showed unexpected high activity for hydrolysis of ammonia borane.

Influence of alcohol solvents on morphology of hollow silica–alumina composite spheres and their activity for hydrolytic dehydrogenation of ammonia borane

In this study, we reported effect of alcohol solvents on morphology of hollow silica–alumina composite spheres and their activity for hydrolytic dehydrogenation of ammonia borane. Silica–alumina composite shell was coated on polystyrene template particles via sol–gel reaction in various alcohol solvents. The hollow spheres were prepared in methanol, ethanol and 2-propanol for 36, 17 and 8 h, respectively. The results indicate that the order of sol–gel reaction rate was 2-propanol > ethanol > methanol. Amount of hydrogen evolution of the hollow spheres prepared in methanol and ethanol were higher than that of the hollow spheres prepared in 2-propanol. From the results of solid-state 27Al nuclear magnetic resonance spectra, we found that aluminum species of the hollow spheres prepared in methanol and ethanol were highly dispersed in their silica matrix. The results of temperature programed dispersion of ammonia showed that all the hollow spheres have weak and strong Bronsted acid sites. The amount of weak Bronsted acid sites in all the hollow spheres were of same level, while the amount of strong Bronsted acid sites increase with decrease of sol–gel reaction rate. These results indicate that the sol–gel reaction rate influences the dispersion of aluminum species, and highly dispersed aluminum species lead to increase in the amount of Bronsted acid sites.

Self-supported Cu(OH)2@Co2CO3(OH)2 core–shell nanowire array as a robust catalyst for ammonia-borane hydrolysis

High hydrogen content and long-term stability in aqueous solutions make ammonia-borane (AB) a promising hydrogen-storage material. It is highly attractive but still challenging to develop efficient catalysts for real-time and controllable hydrogen release from AB solution under mild conditions. Herein, we describe the use of a three-dimensional hierarchical Cu(OH)2@Co2CO3(OH)2 core–shell nanowire array on copper foam (denoted as Cu(OH)2@Co2CO3(OH)2/CF) as a highly efficient catalyst for hydrolytic dehydrogenation of AB. The Cu(OH)2@Co2CO3(OH)2/CF works as an on/off switch for on-demand hydrogen generation with a low activation energy of 44.3 KJ mol−1 and a turnover frequency of 39.72 mol(H2)/mol(cat.)/min. It also maintains activity and integration after long-term usage.

Enhanced catalytic activity of monodispersed AgPd alloy nanoparticles assembled on mesoporous graphitic carbon nitride for the hydrolytic dehydrogenation of ammonia borane under sunlight

We address the composition-controlled synthesis of monodispersed AgPd alloy nanoparticles (NPs), their assembly for the first time on mesoporous graphitic carbon nitride (mpg-C3N4), and the unprecedented catalysis of mpg-C3N4@AgPd in the hydrolytic dehydrogenation of ammonia borane (AB) at room temperature. Monodispersed AgPd alloy NPs were synthesized using a high-temperature organic-phase surfactant-assisted protocol comprising the co-reduction of silver(I) acetate and palladium(II) acetylacetonate in the presence of oleylamine, oleic acid, and 1-octadecene. This protocol allowed the synthesis of four different compositions of AgPd alloy NPs. The AgPd alloy NPs were then assembled on mpg-C3N4, reduced graphene oxide, and Ketjenblack using a liquid-phase self-assembly method. Among the three supports tested, the mpg-C3N4@AgPd catalysts provided the best activity because of the Mott–Schottky effect, which was driven by the favorable work function difference between mpg-C3N4 and the metal NPs. Moreover, the activity of the mpg-C3N4@AgPd catalyst was further enhanced by an acetic acid treatment (AAt), and a record initial turnover frequency of 94.1 mol(hydrogen)·mol (catalyst) −1 ·min−1 was obtained. Furthermore, the mpg-C3N4@Ag42Pd58-AAt catalyst also showed moderate durability for the hydrolysis of AB. This study also includes a wealth of kinetic data for the mpg-C3N4@AgPd-catalyzed hydrolysis of AB.

Monolithically integrated CoP nanowire array: An on/off switch for effective on-demand hydrogen generation via hydrolysis of NaBH4 and NH3BH3

The issues of hydrogen generation and storage have hindered the widespread use and commercialization of hydrogen fuel cell vehicles. It is thus highly attractive, but the design and development of highly active non-noble-metal catalysts for on-demand hydrogen release from alkaline NaBH4 solution under mild conditions remains a key challenge. Herein, we describe the use of CoP nanowire array integrated on a Ti mesh (CoP NA/Ti) as a three-dimensional (3D) monolithic catalyst for efficient hydrolytic dehydrogenation of NaBH4 in basic solutions. The CoP NA/Ti works as an on/off switch for on-demand hydrogen generation at a rate of 6,500 mL/(min·g) and a low activation energy of 41 kJ/mol. It is highly robust for repeated usage after recycling, without sacrificing catalytic performance. Remarkably, this catalyst also performs efficiently for the hydrolysis of NH3BH3.

Cobalt phosphide nanowall arrays supported on carbon cloth: an efficient monolithic non-noble-metal hydrogen evolution catalyst

Hydrogen has been considered as an ideal energy carrier for replacing fossil fuels to mitigate global energy crises. Hydrolysis of sodium borohydride (NaBH4) is simple and effective for hydrogen production but needs active and durable catalysts to accelerate the kinetics. In this paper, we demonstrate that cobalt phosphide nanowall arrays supported on carbon cloth (CoP NAs/CC) efficiently catalyze the hydrolytic dehydrogenation of NaBH4 with an activation energy of 42.1 kJ mol−1 in alkaline media. These monolithic CoP NAs/CC show a maximum hydrogen generation rate of and are robust with superior durability and reusability. They are also excellent in activity and durability for electrochemical hydrogen evolution in 1.0 M KOH, with the need of an overpotential of only 80 mV to drive 10 mA cm−2. They offer us a promising low-cost hydrogen-generating catalyst for applications.

Influence of preparation conditions on morphology of in-situ synthesized hollow ruthenium-silica composite spheres for hydrolytic dehydrogenation of ammonia borane

Hollow ruthenium-silica composite spheres were synthesized from spherical ruthenium-silica composite particles prepared by sol-gel method, followed by in-situ activation in an aqueous sodium borohydride (NaBH4)/ammonia borane (NH3BH3) solutions. Through the preparation of the spherical particles, we investigated influence of promotors (L(+)-arginine and ammonia) on the sol-gel reaction in terms of the morphology of the spherical particle precursors and the hollow spheres. Average particle size of the precursors drastically increased by increasing the amount of L(+)-arginine used, though this also increased the solution pH. Average particle size of the precursors did not significantly increase when concentration of ammonia increased. These results indicate that L(+)-arginine promotes particle growth more effectively than ammonia. The spherical particles prepared with L(+)-arginine shows a higher hydrogen evolution rate and a higher quantity of evolved hydrogen from the aqueous NaBH4/NH3BH3 solution than the spherical particles prepared with ammonia. The spherical particles resulting from in-situ synthesis with sizes ranging from 100 to 950 nm possess hollow voids. UV-Vis spectra of the in-situ synthesized samples indicated that the activity depends on the reducibility of the active ruthenium species. The ruthenium species included in the sample prepared using L(+)-arginine was more metallic than that included in the sample prepared using ammonia.

RuCo NPs supported on MIL-96(Al) as highly active catalysts for the hydrolysis of ammonia borane

Bimetallic RuCo nanoparticles (NPs) were successfully deposited on the highly porous and hydrothermally stable nanofibrous metal-organic framework MIL-96(Al) by using a simple liquid impregnation strategy, and the powder XRD, FT-IR, BET, TEM, EDX, ICP-AES and XPS were employed to characterize the structure, size, composition and loading metal electronic states of the RuCo@MIL-96 catalysts. The catalytic property of RuCo@MIL-96 for hydrogen generation from the hydrolysis of ammonia borane (AB) at room temperature was investigated. The results show that Ru1Co1@MIL-96 exhibits much enhanced catalytic activity compared with monometallic Ru, Co counterparts loadings and RuCo NPs due to the uniform distribution of metal NPs and synergetic effect between Ru and Co particles as well as bi-functional effects between RuCo NPs and the host of MIL-96. The turn over frequency (TOF) value of the Ru1Co1@MIL-96 catalyst is determined to be 320.7 mol H2 min−1 (mol Ru)−1, which is higher than most of the reported TOF values for the same reaction, and the activation energy (Ea) is 36.0 kJ mol−1. Moreover, this catalyst exhibits satisfied durability after five cycles for the hydrolytic dehydrogenation of ammonia borane.

Back Cover: Monodispersed CuCo Nanoparticles Supported on Diamine‐Functionalized Graphene as a Non‐noble Metal Catalyst for Hydrolytic Dehydrogenation of Ammonia Borane (ChemNanoMat 10/2016)

Back Cover: Monodispersed CuCo Nanoparticles Supported on Diamine‐Functionalized Graphene as a Non‐noble Metal Catalyst for Hydrolytic Dehydrogenation of Ammonia Borane (ChemNanoMat 10/2016)

Corrigendum: Carbon Nanotubes as Support in the Platinum-Catalyzed Hydrolytic Dehydrogenation of Ammonia Borane.

In the Full Paper by Duan, Chen et al., incorrect units are shown for the scale bars of the transmission electron microscopy (TEM) images in Figure 1. In each case, the correct unit is nanometer (nm), instead of centimeter (cm). The figure is shown here with correct units. Typical HAADF–STEM images of fresh catalysts as well as deactivated ones after 5 cycles: (a) Pt/CNT-P, (b) Pt/CNT-O, and (c) Pt/CNT-D. The authors and the editorial office apologize for this oversight, and for any inconvenience caused.

Facile Synthesis of Three‐Dimensional Pt‐TiO2 Nano‐networks: A Highly Active Catalyst for the Hydrolytic Dehydrogenation of Ammonia–Borane

AbstractThree‐dimensional (3D) porous metal and metal oxide nanostructures have received considerable interest because organization of inorganic materials into 3D nanomaterials holds extraordinary properties such as low density, high porosity, and high surface area. Supramolecular self‐assembled peptide nanostructures were exploited as an organic template for catalytic 3D Pt‐TiO2 nano‐network fabrication. A 3D peptide nanofiber aerogel was conformally coated with TiO2 by atomic layer deposition (ALD) with angstrom‐level thickness precision. The 3D peptide‐TiO2 nano‐network was further decorated with highly monodisperse Pt nanoparticles by using ozone‐assisted ALD. The 3D TiO2 nano‐network decorated with Pt nanoparticles shows superior catalytic activity in hydrolysis of ammonia–borane, generating three equivalents of H2.

Facile Synthesis of Three-Dimensional Pt-TiO2 Nano-networks: A Highly Active Catalyst for the Hydrolytic Dehydrogenation of Ammonia-Borane.

Three-dimensional (3D) porous metal and metal oxide nanostructures have received considerable interest because organization of inorganic materials into 3D nanomaterials holds extraordinary properties such as low density, high porosity, and high surface area. Supramolecular self-assembled peptide nanostructures were exploited as an organic template for catalytic 3D Pt-TiO2 nano-network fabrication. A 3D peptide nanofiber aerogel was conformally coated with TiO2 by atomic layer deposition (ALD) with angstrom-level thickness precision. The 3D peptide-TiO2 nano-network was further decorated with highly monodisperse Pt nanoparticles by using ozone-assisted ALD. The 3D TiO2 nano-network decorated with Pt nanoparticles shows superior catalytic activity in hydrolysis of ammonia-borane, generating three equivalents of H2 .

Inside Cover: High Catalytic Performance of MIL‐101‐Immobilized NiRu Alloy Nanoparticles towards the Hydrolytic Dehydrogenation of Ammonia Borane (Eur. J. Inorg. Chem. 27/2016)

Inside Cover: High Catalytic Performance of MIL‐101‐Immobilized NiRu Alloy Nanoparticles towards the Hydrolytic Dehydrogenation of Ammonia Borane (Eur. J. Inorg. Chem. 27/2016)