Ammonia Borane Research Articles

Development of continuous measurement system for hydrogen and impurity gases using detector tube.

A relatively accurate, inexpensive, simple, and continuous quantification system for hydrogen and impurity gas(es) using a detector tube was developed in this study. Additionally, different detector tubes can be applied to measure different types of gases in a wide range from ppm order to % level. We optimized this system and evaluated its accuracy as well as the behavior of released H2 and impurity (NH3) gases from a hydrolysis of ammonia borane using a Pt/Al2O3 catalyst. The accuracy of hydrogen quantitation achieved by this system was comparable to that of commercial mass flow meters, and the accuracy of ammonia quantitation was 10% or 5% relative standard deviation, which depends on the detector tube. The concentration of released NH3 was evaluated by image analysis with a time-lapse video of the detector tube and succeeded in analyzing from ppm to % order. The H2 and NH3 release behaviors agreed with pH, and the percentage of reaction was estimated by NMR measurement of the reacted solution. These results confirmed the accuracy of this system.

Cover Feature: Production of Dihydrogen Using Ammonia Borane as Reagent and Pyrazole as Catalyst (ChemPhysChem 17/2023)

Cover Feature: Production of Dihydrogen Using Ammonia Borane as Reagent and Pyrazole as Catalyst (ChemPhysChem 17/2023)

Mechanism, Kinetics and Simulation of Electrocatalytic Oxidation of Dimethylamine Borane (DMAB) on Electroless Gold

Dimethylamine borane ((CH3)2NHBH3) or DMAB, is broadly used as a reducing agent in electroless autocatalytic platings like gold and nickel-boron, hydrogen storage, and reductive amination. However, the mechanism of its DMAB oxidation procedure remains unclear. This project is based on the hypothesis that a multi-step electron transfer mechanism exists for oxidizing the reducing agent DMAB on gold in alkaline media. According to this mechanism, the active species produced when DMAB is used at high hydroxide content is the BH3OH-. This species is created through a series of irreversible electrochemical oxidation producing the following intermediates BH2(OH)2-, BH(OH)3- and B(OH)4-, which is the final product. Multiple electrochemical methods have been used to uncover the properties of DMAB oxidation progress and verify above-mentioned hypothesis. Electrochemical Impedance Spectroscopy (EIS) was used to test the uncompensated resistance between the working electrode and reference electrode and calibrated in the following experiments: Cyclic voltammetry (CV) showed that DMAB in hydroxide electrolytes have three half-wave potentials with E_(1/2) of -0.778, -0.174 and 0.248 V. Kinetic current values obtained from the Koutecky-Levich plot decreased with temperature with -4.065, -3.62 and -1.45 mA/cm2 at 25°C, 41°C and 52°C, respectively. Rotating Disk Electrode (RDE) and Chronoamperometry (CA) were used to determine the Diffusion Coefficient of BH3(OH)-; BH2(OH)2- and BH(OH)3- 1.38E-05, 3.31E-05 and 1.01E-04, respectively. Tafel analysis was used in obtaining the transfer coefficient, whereas Klingler and Kochi’s method evaluated the constant. These kinetic parameters were used in KISSA-1D software to simulate the CVs. Gas Chromatography with Mass Spectrometry (GC/MS) was used to verify the existence of B(OH)4- and a peak at m/z 78.8 was recorded. All of this provided evidence that the three intermediates are involved in the proposed mechanism. In the future, simulated and experimental approaches will be investigated for other amine boranes compounds such as Sodium cyanoborohydride (NaBH3CN), Sodium triacetoxyborohydride (NaBH(O2CCH3)3), and Sodium borohydride (NaBH4). This work will have far-reaching consequences in enhancing the practical applications of gold and nickel in microelectronics and fuel cells.

Green and active hydrogen production from hydrolysis of ammonia borane by using caffeine carbon quantum dot-supported ruthenium catalyst in methanol solvent by hydrothermal treatment

Here, carbon quantum dot (CQD) supported Ru nanoparticles from the caffeine in methanol or water by the hydrothermal method were synthesized for the first time to produce hydrogen (H2) by hydrolysis of ammonia borane(NH3BH3) and their catalytic activities were investigated. The chemical compositions and morphology structures of this caffeine carbon dot-supported Ru catalysts were carefully characterized by UV, PL, TEM, FTIR, and ICP/OES analyses. Well-dispersed Ru nanoclusters with ∼1.81 nm particle size on CQD by the hydrothermal method in methanol medium showed very good catalytic performance. The turnover frequency (TOF) obtained for H2 production from the catalytic hydrolysis of 5% NH3BH3 with CQD supported Ru catalyst obtained by the hydrothermal method in methanol and water was found to be 361 and 1895 mol H2 min−1 mol−1, respectively. The activation energies (Ea) for NH3BH3 hydrolysis with the same catalysts were measured as 33.32 and 27.80 kJmol-1, respectively.

Effect of pre-annealing on chemical configuration and heteroatom doping of highly active carbon catalysts for the oxygen reduction reaction

Heteroatom-doped carbon catalysts are promising alternatives to platinum group metal-free catalysts for oxygen reduction reaction (ORR). To enhance the ORR activity of carbon-based catalysts, the break of electroneutrality and number of active sites must be maximized. In this study, an annealing process at a mild temperature was introduced before heteroatom doping to control the content and configuration of the oxygen functional groups on the graphene oxide (GO). Pre-annealing affects the chemical configuration and the porosity of GO such that the epoxy groups are converted into carbonyl groups accompanying the defect formation. Interestingly, The carbonyl-enriched environment allowed ammonia borane, as a dopant with nitrogen and boron atoms, the enhanced doping performance, inducing the formation of higher number of heteroatom doping sites and additional defects in the graphene lattice. The aBNG-150 catalyst demonstrated outstanding ORR activity in both half- and single-cell evaluations because it had the highest heteroatom content and meso/macropores derived from the elimination of oxygen functional groups, which can facilitate ORR catalytic activity and O2 diffusion pathway. Therefore, we believe that this approach provides an effective route for synthesizing carbon-based catalysts with remarkable ORR performances.

Nanostructured Carbon-Doped BN for CO2 Capture Applications.

Carbon-doped boron nitride (denoted by BN/C) was prepared through the pyrolysis at 1100 °C of a nanostructured mixture of an alkyl amine borane adduct and ammonia borane. The alkyl amine borane adduct acts as a soft template to obtain nanospheres. This bottom-up approach for the synthesis of nanostructured BN/C is relatively simple and compelling. It allows the structure obtained during the emulsion process to be kept. The final BN/C materials are microporous, with interconnected pores in the nanometer range (0.8 nm), a large specific surface area of up to 767 m2·g-1 and a pore volume of 0.32 cm3·g-1. The gas sorption studied with CO2 demonstrated an appealing uptake of 3.43 mmol·g-1 at 0 °C, a high CO2/N2 selectivity (21) and 99% recyclability after up to five adsorption-desorption cycles.

Tandem catalytic hydrogen gas generation and reduction of nitro aromatic derivatives via hydrolysis of ammonia borane over Ag NPs@ZIF-8 nanocomposites in aqueous media

In this research, three composites composed of ZIF-8 metal–organic framework and silver nanoparticles (Ag NPs) with different mole ratios were successfully synthesized. The fabricated Ag NPs@ZIF-8 composites were characterized by Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), energy-dispersive X-ray (EDX) mapping, field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM) techniques. The composite Ag NPs@ZIF-8 (1:1 mol ratio) was also characterized by Brunauer–Emmett–Teller (BET) and X-ray photoelectron spectroscopy (XPS) analyses. Catalytic activity of the Ag NPs@ZIF-8 composites in tandem hydrogen generation from ammonia borane (H3N-BH3) and reduction of nitro-aromatic derivatives was investigated in one-pot reactions. The rate of evaluated H2 gas from the hydrolysis of H3N-BH3 by the Ag NPs@ZIF-8 (1:1) composite was measured to be about 198.9 (mL/g−1.min−1) in these catalytic reactions. Various derivatives of nitro compounds, including electron-withdrawing and electron-donating groups were converted to the corresponding amines with excellent yields by this catalytic system in less than one hour.

Magnetically isolable Pd(0) nanoparticles supported on surface functionalized Fe3O4 for hydrogen generation via ammonia borane hydrolysis

AbstractPd(0) nanoparticles supported on surface functionalized magnetite (Fe3O4/SiO2‐NH2/HB@Pd) were prepared as catalyst for hydrolysis of ammonia borane (AB). The obtained magnetic nanocomposite material was seperated from the reaction media through a permanent magnet and characterized by FT‐IR, XRD, SEM‐EDX, TEM, ICP‐OES and XPS techniques. 100 mg Fe3O4/SiO2−NH2/HB@Pd nanocomposite with Pd metal content of 6.00±0.14 catalyzed the hydrolysis of 10 mM AB at 25 °C with 100 % yield. The presented work includes the effect of catalyst amount and temperature on the rate of the hydrolysis reaction of AB. As a result of the kinetic studies, the activation energy (Ea) for the Fe3O4/SiO2−NH2/HB@Pd catalyzed AB hydrolysis reaction was calculated as 34±1 kJ.mol−1, and the TOF value was calculated as 133 mol H2.(mol Pd(0).h)−1. The designed heterogenous magnetic nanocomposite catalyst demonstrated significant catalytic activity for AB hydrolysis reaction at 25 °C.

Boron-doping-induced modulation of structural parameters of pristine commercial carbon black for promoting Ru-catalyzed O[sbnd]H bond activation toward hydrogen evolution

Owing to the lack of adequate nucleation sites for metal nanoparticles (NPs) and weak metal-support interaction, pristine carbon materials supported metal NPs suffer from limited surface-exposed active sites and thereby low catalytic activity. Herein, we report a sodium borohydride-mediated modification of commercial Valcan carbon (VC) to produce B-doped VC (BVC) as a useful support to deposit Ru NPs (Ru/BVC) for hydrogen production from ammonia borane hydrolysis (ABH). The B-doping endows BVC with not only more surface functional groups and defect sites but also abundant meso/macroporous structure and hydrophilic surface, facilitating the generation of uniformly dispersed ultra-small Ru NPs (d = 1.42 nm) with strong electronic metal-support interaction. The optimal Ru/BVC catalyst exhibits an excellent activity with a turnover frequency of 1577.0 min−1 (depending on Ru dispersion). Isotopic and alkali promotion experiments unveil the rate-determining step (RDS) for ABH is the oxidative cleavage of the OH bond in water. The copious surface-exposed active sites and the regulated electron distribution between Ru NPs and BVC efficiently reduce the energy barrier for RDS, thereby promoting catalytic performance of hydrogen evolution from ABH. This simple and efficient heteroatom-doping strategy is easily extended to fabricate efficient catalysts with promoted performance for catalytic applications.

Transfer Hydrogenation of Azoarenes to Hydrazoarenes by Ammonia Borane Complex Catalyzed by Au Nanoparticles

AbstractMinute amounts of supported Au nanoparticles on TiO2 (0.1 mol%) catalyze quantitatively at room temperature the transfer hydrogenation of azoarenes to hydrazoarenes by ammonia borane complex, in ethanol as solvent. At 1 mol% catalyst loading level and 2.5 molar equivalents of ammonia borane the process occurs instantaneously. The catalyst is recyclable and reusable. In the absence of reducing agent, hydrazoarenes undergo smooth Au/TiO2‐catalyzed aerobic oxidation back to azoarenes.

Regeneration of Co-based bead type catalyst in ammonia borane hydrolysis for hydrogen generation: Artificial neural networks and response surface methodology

The usage of ammonia borane (NH3BH3, AB) as a hydrogen storage medium and the release of hydrogen from its structure via hydrolysis has gained attention as for the hydrogen energy systems. Cobalt (Co)-based catalysts are the one of the activist material that can effectively catalyze the hydrogen production at current applications. However, Co-based catalysts have gradually lost their initial activities in long-term reactions due to by-product deposition on their surface. To address this issue, a catalyst regeneration strategy based on solvent washing to re-activation of Co-based catalysts with help of new perspective is presented in this study. Regeneration parameters as solution properties (pH:3–7), temperature (15–75 °C), and duration (10–50 min) have been modeled by both Response Surface Methodology (RSM) and Artificial Neural Network (ANN) techniques with different levels to optimize the process conditions for the regeneration process and to regain the high initial catalytic activity. The results have showed that solvent washing at optimization conditions was the effective method for restoring the activity of the catalyst. The findings indicate that time and temperature have a significant impact on the regeneration of the Co-based catalyst. The characterization techniques such as XRD, FTIR, HR-TEM, SEM/EDS, and XPS were performed to illuminate and correlate the effect of regeneration on the internal and external properties of fresh, used and regenerated catalysts. The optimum regeneration conditions, the pH of 6.5, the temperature of 44 °C, and the duration of 42 min under the optimal conditions identified by RSM, provided the highest hydrogen production (3.23 l min−1.g−1), showed much closer results to ANN technique predicted value (3.45 l min−1.g−1). It is shown that ANN has a relatively higher prediction accuracy and optimization ability compared to RSM for hydrogen production rate.

Preparation of rice husk-based carbon supported ruthenium catalyst for the hydrolysis of ammonia borane to produce hydrogen

An efficient dehydrogenation catalyst is crucial for the application of ammonia borane (NH3BH3, AB) as a solid chemical hydrogen storage material. In this work, a kind of nitrogen-doped rice husk activated carbon (N-RHC) was prepared by roasting melamine and rice husk at high temperature under nitrogen atmosphere. With N-RHC as the support, the rice husk-based carbon supported ruthenium catalyst (Ru/N-RHC) was prepared through impregnation with the RuCl3 solution and its catalytic performance in the hydrolysis of ammonia borane to produce hydrogen was investigated. The results indicate that the Ru/N-RHC catalyst with a Ru loading of 5% performs excellently in the hydrolysis of ammonia borane; the reaction turnover frequency (TOF) reaches 83.71 min−1 and the apparent activation energy decreases from 88.9 to 64.9 kJ/mol under light irradiation. In addition, the hydrogen production rate is positively correlated with the content of ammonia borane and catalyst.

Synthesis of Ilmenite Nickel Titanite-Supported Carbon Nanofibers Derived from Polyvinylpyrrolidone as Photocatalyst for H2 Production from Ammonia Borane Photohydrolysis.

The present study involves the synthesis of photocatalytic composite nanofibers (NFs) comprising ilmenite nickel titanite-supported carbon nanofibers (NiTiO3/TiO2@CNFs) using an electrospinning process. The photocatalytic composite NFs obtained were utilized in hydrogen (H2) production from the photohydrolysis of ammonia borane (AB). The experimental findings show that the photocatalytic composite NFs with a loading of 25 mg had a good catalytic performance for H2 generation, producing the stoichiometric H2 in 11 min using 1 mmol AB under visible light at 25 °C and 1000 rpm. The increase in catalyst load to 50, 75, and 100 mg leads to a corresponding reduction in the reaction time to 7, 5, and 4 min. The findings from the kinetics investigations suggest that the rate of the photohydrolysis reaction is directly proportional to the amount of catalyst in the reaction system, adhering to a first-order reaction rate. Furthermore, it was observed that the reaction rate remains unaffected by the concentration of AB, thereby suggesting a reaction of zero order. Increasing the reaction temperature results in a decrease in the duration of the photohydrolysis reaction. Furthermore, an estimated activation energy value of 35.19 kJ mol-1 was obtained. The composite nanofibers demonstrated remarkable and consistent effectiveness throughout five consecutive cycles. The results suggest that composite NFs possess the capacity to function as a feasible substitute for costly catalysts in the process of H2 generation from AB.

Space Station-like Composite Nanoparticles for Co-Delivery of Multiple Natural Compounds from Chinese Medicine and Hydrogen in Combating Sensorineural Hearing Loss.

Ototoxic drugs such as aminoglycoside antibiotics and cisplatin (CDDP) can cause sensorineural hearing loss (SNHL), which is closely related to oxidative stress and the acidification of the inner ear microenvironment. Effective treatment of SNHL often requires multifaceted approach due to the complex pathology, and drug combination therapy is expected to be at the forefront of modern hearing loss treatment. Here, space-station-like composite nanoparticles (CCC@mPP NPs) with pH/oxidation dual responsiveness and multidrug simultaneous delivery capability were constructed and then loaded with various drugs including panax notoginseng saponins (PNS), tanshinone IIA (TSIIA), and ammonia borane (AB) to provide robust protection against SNHL. Molecular dynamics simulation revealed that carboxymethyl chitosan/calcium carbonate-chitosan (CCC) NPs and monomethoxy poly(ethylene glycol)-PLGA (mPP) NPs can rendezvous and dock primarily by hydrogen bonding, and electrostatic forces may be involved. Moreover, CCC@mPP NPs crossed the round window membrane (RWM) and entered the inner ear through endocytosis and paracellular pathway. The docking state was basically maintained during this process, which created favorable conditions for multidrug delivery. This nanosystem was highly sensitive to pH and reactive oxygen species (ROS) changes, as evidenced by the restricted release of payload at alkaline condition (pH 7.4) without ROS, while significantly promoting the release in acidic condition (pH 5.0 and 6.0) with ROS. TSIIA/PNS/AB-loaded CCC@mPP NPs almost completely preserved the hair cells and remained the hearing threshold shift within normal limits in aminoglycoside- or CDDP-treated guinea pigs. Further experiments demonstrated that the protective mechanisms of TSIIA/PNS/AB-loaded CCC@mPP NPs involved direct and indirect scavenging of excessive ROS, and reduced release of pro-inflammatory cytokines. Both in vitro and in vivo experiments showed the high biocompatibility of the composite NPs, even after long-term administration. Collectively, this work suggests that composite NPs is an ideal multi-drug-delivery vehicle and open new avenues for inner ear disease therapies.

Fundamental Properties of Ammonia Borane Aqueous Solution: Dissolution Enthalpy of Solution, Freezing Points and Solubility Curve, Thermal analysis, Stability and Phase Diagram

Fundamental Properties of Ammonia Borane Aqueous Solution: Dissolution Enthalpy of Solution, Freezing Points and Solubility Curve, Thermal analysis, Stability and Phase Diagram

Boron nitride nanotubes synthesis from ammonia borane by an inductively coupled plasma

Boron nitride nanotubes (BNNTs) have been studied extensively due to their unique properties. Hydrogen-assisted induction thermal plasma with hBN powder has been reported in the past to produce high-yield small-diameter BNNTs. However, removal of unprocessed hBN and other BN-based impurities has been a challenge. This study presents a new approach for BNNT synthesis using ammonia borane (AB) as the raw material while maintaining the high yield and similar nanotube diameter and number of walls. Our findings demonstrate that the use of AB results in enhanced synthesis of BNNTs with reduced B and BN impurities formation. The presence of H in the proximity of B following AB decomposition facilitated more efficient formation of BH-based precursors that also lowered the partial pressure of B and restricted its condensation and coagulation into large B particles, ultimately leading to an increased density of B seeds required for BNNTs nucleation. Both the increased formation of BNNT precursors and B seeds contributed to more efficient BNNTs formation. XRD analysis revealed that AB-BNNTs contained no hBN, less tBN, and more BNNTs compared to hBN-BNNTs. Additionally, TGA and OES measurements confirmed formation of less B and production of more BH species, respectively. Our results suggest that AB as a feedstock for BNNT synthesis in induction thermal plasma offers a promising alternative to hBN powder.

Visible light-assisted hydrogen generation from ammonia borane over Z-Scheme NiO-CuO heterostructures

The design and fabrication of cheap and high-efficiency catalysts for ammonia borane (AB) hydrolysis for hydrogen production is crucial for its commercial applications. Improvement of the catalytic performance of the catalysts with the assistance of sunlight, a costless resource, is extremely attractive. Herein, we have constructed Z-scheme heterostructured VO-NiO-CuO catalysts with strong interfacial electronic interactions and abundant oxygen vacancies to enhance hydrogen production from NH3BH3 solution under visible light illumination. The as-prepared VO-NiO-CuO catalysts exhibit excellent catalytic activity with a high turnover frequency (TOF) of 35.3 molH2 molcat.-1 min−1 toward AB hydrolysis under visible light. It is demonstrated that excellent catalytic performance is highly related to the effective separation and migration of charge on the catalyst surface. As a result, dual active sites were created, making it easier for various reactants to be adsorbed and activated on the catalyst surface. Furthermore, the density functional theory (DFT) calculations indicate that the adsorption and activation of H2O occurred mainly at the Ni site of VO-NiO-CuO. When the VO-NiO-CuO is irradiated with visible light, the photogenerated electrons assembled on the conduction band were transferred to the O atom through the Ni-O bond, which made the bond length of H2O molecules longer and OH bonds more prone to breaking, thus facilitating AB hydrolysis under illumination. The findings in this work pave the way to design novel and efficient heterostructured catalysts for fast hydrogen release from NH3BH3 under visible light irradiation.

Production of Dihydrogen Using Ammonia Borane as Reagent and Pyrazole as Catalyst.

Theoretical chemistry (DLPNO-CCSD(T)/def2-TZVP//M06-2x/aug-cc-pVDZ) was used to design a system based on ammonia boranes catalyzed by pyrazoles with the aim of producing dihydrogen, nowadays of high interest as clean fuel. The reactivity of ammonia borane and cyclotriborazane were investigated, including catalytic activation through 1H-pyrazole, 4-methoxy-1H-pyrazole, and 4-nitro-1H-pyrazole. The results point toward a catalytic cycle by which, at the same time, ammonia borane can initially store and then, through catalysis, produce dihydrogen and amino borane. Subsequently, amino borane can trimerize to form cyclotriborazane that, in presence of the same catalyst, can also produce dihydrogen. This study proposes therefore a consistent progress in using environmentally sustainable (metal free) catalysts to efficiently extract dihydrogen from small B-N bonded molecules.

Novel synthesis of ammonia borane fluoride induced ZIF67 derivatives using facile one-step solution process for energy storage

Battery and supercapacitor hybrids (BSH) are regarded as efficient energy storage devices due to their high energy and power densities. Metal organic frameworks (MOF) with enhanced electrical conductivity by post treatments are widely utilized as electroactive materials in BSH, but in-situ modifications are considered better ways to improve charge storage in MOF due to their lower cost in money and time. Ammonium fluoride has been intensively used as a structure directing agents (SDA) for designing electroactive materials. Based on benefits from the ammonium cation group and fluorine-based anion group, ammonium tetrafluoroborate (NH4BF4) is applied as the novel SDA to design a series of zeolitic imidazolate framework-67 (ZIF67) derivatives using a one-step solution process as the electroactive material of BSH in this work. The ratio of 2-methylimidazole and NH4BF4 has a large influence on compositions and surface properties. The largest specific capacitance (CF) of 1593.1 F/g is obtained for the optimal ZIF67 derivative owing to the high surface area, large pore volume, and high occupation of metal hydroxide. The optimal ZIF67 derivative and reduced graphene oxide are used to assemble a BSH, which presents a maximum energy density of 15.1 Wh/kg at 857.1 W/kg. The CF retention of 87.5% and Coulombic efficiency of 97.2% after 6000 cycles are also obtained.

Amino-functionalized CuFe2O4 supported Pd nanoparticles as magnetically catalyst for H2 production from methanolysis of ammonia borane and hydrogenation of nitro aromatics

Small and equally distributed Pd nanoparticles (NPs) are tightly anchored on the surface of magnetic and amino (–NH2) functionalized CuFe2O4 to obtain magnetically separable CuFe2O4–NH2@Pd catalyst with core-shell structure. Compared to the inherent catalytic activity of CuFe2O4, the catalytic performance of CuFe2O4–NH2@Pd for dehydrogenation of ammonia-borane (AB) and concurrent hydrogenation of different nitro aromatics by H2 generated from AB methanolysis can be boosted more effectively than that of CuFe2O4@Pd, which is the control catalyst and is prepared by loading Pd NPs on pristine CuFe2O4. As electron donating groups, the –NH2 groups covalently bonded to the surface of CuFe2O4 play vital roles in stabilizing Pd NPs, providing strong metal-support interaction and rendering enhanced catalytic activity. However, we find that the catalytic performance of CuFe2O4, CuFe2O4@Pd and CuFe2O4–NH2@Pd for the hydrogenation reduction of mercapto-substituted nitro aromatics (p-nitrothiophenol, p-NTP) is far inferior to that for the reduction of nitroarenes that do not contain a sulfur substituent. Therefore, it is quite essential to research and develop the new-type catalysts with more excellent catalytic performance.