Hydrazine Borane Research Articles

Electrochemical Reactivity of Hydrogen Storage Materials: Exploring Borohydride and Hydrazinium Salt Mixtures

Electrochemical characterization of hydrogen storage materials was conducted in a non-aqueous environment to investigate the direct electrochemical release and consumption of hydrogen and the potential for regeneration. We first address the challenge of minimal solubility of the synthetic precursors, sodium borohydride (NaBH4) and hydrazinium bromide (N2H5Br), in both organic and inorganic solvents. We next determine and calibrate a reference electrode formulation compatible with our non-aqueous media and analytes that demonstrates a stable reference potential. We employ cyclic voltammetry (CV) to characterize the precursors and mixtures thereof. Each CV peak is assigned to a corresponding electrochemical reaction. Using the rate-dependent CV method and Randles–Ševčík equation, we calculate the diffusion coefficient of each chemical (NaBH4 and N2H5Br). Analysis of the CVs, coupled with 11B NMR analysis, reveals a room temperature chemical transformation of NaBH4 and N2H5Br mixtures into hydrazine borane (N2H4BH3). These results are particularly significant, considering the limited information available on the electrochemical characterization of metal borohydride and hydrazinium salt in non-aqueous media. This work establishes a foundation for adapting a non-aqueous electrochemical system to further study the borohydride family of chemistries and to design and develop electrochemical devices for direct electrical and chemical energy interconversion with hydrogen storage materials.

Rapid and complete hydrazine borane decomposition for hydrogen production catalyzed by CoPt/CNTs at room temperature

Recently, hydrazine borane (HB, N2H4BH3) is recognized as an ideal chemical hydrogen storage material due to its high efficiency in storing hydrogen and excellent stability. However, finding an efficient, stable, and low-cost catalyst is still a challenge. In this study, CoPt nanoparticles (NPs) supported on carbon nanotubes (CNTs) are prepared at room temperature. The Co0.4Pt0.6/CNTs catalyst exhibits optimal catalytic performance for hydrogen production from HB at ambient conditions, achieving a total turnover frequency (TOF) value of 1525.4 h−1 and 100% H2 selectivity. The well-dispersed CoPt NPs on CNTs and the synergistic effect between Co and Pt further enhance the decomposition efficiency of HB. This high-performance catalyst has significant implications for the advancement of hydrogen storage materials, particularly in relation to HB.

Design of TiO2-based bi-functional catalyst and the catalytic mechanism of enhanced hydrazine borane hydrolysis for hydrogen production

In this study, a scheme of photocatalytic coupled metal catalytic synergistic enhancement of hydrazine borane hydrolysis is proposed, the catalytic reaction mechanism for hydrogen production from hydrazine borane hydrolysis is revealed. In addition, the effects of solvent property, external electric field conditions on the stability of N2H4BH3 molecule are also investigated systematacially. The results show that the band structure of pure TiO2 can be modulated by heterogeneous element N, C, Ni, Ru, the modification effect of co-doping with heterogeneous alloy elements (eg. NiPt@N–TiO2) is best in all doping schemes. The hydrolysis reaction of -BH3 of N2H4BH3 catalyzed by Pt metal is a stepwise dehydrogenation reaction, and the energy barrier of the reaction rate-determining of the B–N bond breakage is 50.49 kcal/mol. There are two possible cleavage reaction pathways for N2H4, which are hydrogen-producing pathway and ammonia-producing pathway, the energy barrier for the reaction rate-determining step is 67.06 kcal/mol and 82.51 kcal/mol, respectively, the hydrogen production reaction takes precedence over the ammonia production reaction. OH− solution is best among the neutral aqueous solution, rich H+, NH4+ and NaOH solution in B–H bond activation of N2H4BH3 molecule, the external electric field can promote the activation of B–H bond in hydrazine borane hydrolysis system, which is positive factor in improving the performance of hydrazine borane hydrolysis.

Innovation in the synthesis of hydrazine borane by mechanochemical method and hydrolysis of hydrazine borane with Pd/TiO2 catalyst

With its high hydrogen content (15.4 wt%), hydrazine borane (HB, N2H4BH3) is a promising hydrogen storage material. It is easy to prepare and does not create harmful substances during the release of hydrogen, making it suitable for research. In this study, hydrazine borane was synthesized using two methods, one was solution phase synthesis method (literature method), and the other solid state synthesis method (mechanochemical). For the first time, we report a mechanochemical synthesis of HB from the hydrazine hemisulfate salt, sodium borohydride. HB was characterized by B NMR, FTIR, and XRD. Furthermore,the use of nanostructured titanium dioxide (TiO2) supported Pd metallic catalyst in HB hydrolysis was investigated to production hydrogen.

Palladium (0) nanoparticles distributed on lanthanum (III) oxide as an effective catalyst for the methanolysis of hydrazine-borane to produce hydrogen.

Pd (0) nanoparticles (NPs) distributed on lanthanum (III) oxide were ex situ generated from the reduction of Pd2+ ions using NaBH4 as reducing agent. The Pd/La2O3 displayed good catalytic activity in H2(g) releasing from the hydrazine-borane (HB) methanolysis reaction and it was identified by advanced techniques. Pd/La2O3 was found to be an active catalyst procuring three equiv. H2(g) per mole of HB. The results from TEM images represent the formation of Pd (0) NPs with an average particle size of 1.94 ± 0.1 nm on the surface of La2O3. Moreover, Pd/La2O3 with various Pd loadings were prepared and tested as catalyst in the methanolysis reaction to find the optimum metal loading on La2O3 support. The highest H2 formation rate was achieved with 3.0 wt% Pd. Pd/La2O3 catalyst exhibited a turnover frequency (TOF) value of 24.4 mol H2 mol Pd-1 min-1 in the reaction conditions. Additionally, the effect of different catalyst concentrations and temperatures on the reaction kinetics for the methanolysis of HB catalyzed by Pd/La2O3.

Synergistic interaction between NiPt nanoparticles and phosphorus-doped graphene support boosts hydrogen generation from hydrazine borane

The Ni0.6Pt0.4/P-rGO catalyst exhibits excellent catalytic activity and recycling stability for hydrazine borane dehydrogenation at 323 K.

Hydrogen production from complete dehydrogenation of hydrazine borane on carbon-doped TiO2-supported NiCr catalysts

C-doped mesoporous TiO2-supported Cr(OH)3 modified Ni nanoparticles (Ni–Cr/CTO) with different morphologies were synthesized by a simple wet-chemical method and used as efficient catalysts for hydrogen production from hydrazine borane.

Study on a direct hydrazine borane fuel cell based on an anion exchange membrane

The carbon-supported cobalt hydroxide (Co(OH)2–C–PPY) can catalyze N2H4BH3 to produce H2O and BO2−. Furthermore, the optimized anion exchange membrane-type direct hydrazine borane fuel cell achieves a high performance of 244 mW cm−2.

Rh0.7Ru0.3-MoOx supported on carbon nanotubes boosts hydrogen generation from hydrazine borane at room temperature

Hydrazine borane (HB, N2H4BH3) is gaining attention as a promising chemical hydrogen storage material due to its impressive hydrogen capacity (15.4 wt%) and stability under normal conditions. However, its dehydrogenation properties have remained unsatisfactory despite numerous efforts. In this study, we have successfully developed rhodium-ruthenium nanoparticles modified with MoOx and supported on carbon nanotubes (Rh0.7Ru0.3-MoOx/CNTS) using a facile co-reduction method. Surprisingly, the Rh0.7Ru0.3-MoOx/CNTS catalyst exhibits outstanding performance, surpassing all previously reported activities for HB dehydrogenation. It demonstrates a high turnover frequency (TOF) value of 4412 h−1 at 303 K, 100 % selective conversion of hydrogen, and excellent stability. Through XPS, TEM, BET, and XRD analysis, we have determined that the exceptional performance of Rh0.7Ru0.3-MoOx/CNTS can be attributed to the synergistic effect of CNTS and MoOx on the catalyst's electronic structure, crystal structure, and particle size. These results provide a solid foundation for the potential application of HB in hydrogen fuel cells.

Y2O3-functionalized graphene-immobilized Ni–Pt nanoparticles for enhanced hydrous hydrazine and hydrazine borane dehydrogenation

Y2O3-functionalized graphene-immobilized Ni–Pt nanoparticles for enhanced hydrous hydrazine and hydrazine borane dehydrogenation

Carbon-doped mesoporous TiO2-immobilized Ni nanoparticles: Oxygen defect engineering enhances hydrogen production

Constructing efficient, durable, and economical catalysts to promote hydrogen production from hydrous hydrazine (N2H4·H2O) is crucial, but still a great challenge. Herein, noble-metal-free Cr(OH)3-modified Ni nanoparticles (NPs) (2.7 nm) supported on defect-rich carbon-doped mesoporous TiO2 nanosheets (C-TiO2) were prepared for the first time via a simple and green wet-chemistry approach, in which the amount of oxygen defect in C-TiO2 can be easily regulated by adjusting the amount of carbon doping. Significantly, the defect rich Ni-Cr(OH)3/C-TiO2 catalyst presented 100% H2 selectivity, ultrahigh catalytic activity, and remarkable durability for N2H4·H2O dehydrogenation, with a turnover frequency (TOF) value of 266 h−1 at 323 K, more than 6-fold improvement than that of the Ni-Cr(OH)3/TiO2 (41 h−1), which is among the highest values reported so far for noble-metal-free catalysts. The superior catalytic efficiency and durability are mainly owing to the small-sized and electron-rich of Ni NPs induced by the oxygen defects in C-TiO2, where the more oxygen defects, the better the catalytic activity. Furthermore, the catalyst also showed outstanding catalytic efficiency (TOF = 577 h−1) and robust durability for complete dehydrogenation of hydrazine borane (N2H4BH3) at 323 K. This work provides inspiration for the construction of defect engineering and new insights for the development of low-cost and efficient heterogeneous hydrogen production catalysts.

Thermochemical and kinetic investigation of the hydrazine borane as an alternative to hydrazine: The N2H4BH3 + H reactional system

The properties of hydrazine borane (N2H4BH3) were studied to assess its potential as an alternative fuel for use in space missions. The reactions of N2H4BH3 with atomic hydrogen were explored through three different elementary steps, and the thermochemical properties were determined using ab initio methods and density functional theory. The hydrogen abstraction from the borane group had the lowest adiabatic barrier height and all reactions were exothermic. The rate coefficient for hydrogen abstraction from the borane group was 1.4×10−13cm3molecule−1s−1 at 350 K, and N2H4BH3 was found to have better kinetic stability than hydrazine at intermediate and low temperatures.

Replacing Oxygen Evolution with Hydrazine Borane Oxidation for Energy-Saving Electrochemical Hydrogen Production.

Electrochemical water splitting is a green strategy for hydrogen (H2) production but is severely hindered by the sluggish anodic oxygen evolution reaction (OER). Therefore, replacing the sluggish anodic OER with more favorable oxidation reactions is an energy-saving approach for hydrogen production. Hydrazine borane (HB, N2H4BH3) is considered a potential hydrogen storage material due to its easy preparation, nontoxicity, and high chemical stability. Furthermore, the complete electrooxidation of HB has a unique characteristic of a much lower potential compared to that of OER. All these make it an ideal alternative for energy-saving electrochemical hydrogen production, however, which has never been reported so far. Herein, HB oxidation (HBOR)-assisted overall water splitting (OWS) is proposed for the first time for energy-saving electrochemical hydrogen production. The as-synthesized NiCoP@CoFeP nanoneedle array catalyst exhibited superefficient OER, hydrogen evolution reaction (HER), and HBOR performance. Impressively, NiCoP@CoFeP serves as both anodic and cathodic electrocatalysts for HB-assisted OWS, only requires a low cell voltage of only 0.078 V to achieve a current density of 10 mA cm-2, which was 1.4 V lower than that for HB-free OWS, indicating the highly energy-saving H2 production.

Nanosizing Approach-A Case Study on the Thermal Decomposition of Hydrazine Borane.

Hydrazine borane (HB) is a chemical hydrogen storage material with high gravimetric hydrogen density of 15.4 wt%, containing both protic and hydridic hydrogen. However, its limitation is the formation of unfavorable gaseous by-products, such as hydrazine (N2H4) and ammonia (NH3), which are poisons to fuel cell catalyst, upon pyrolysis. Previous studies proved that confinement of ammonia borane (AB) greatly improved the dehydrogenation kinetics and thermodynamics. They function by reducing the particle size of AB and establishing bonds between silica functional groups and AB molecules. In current study, we employed the same strategy using MCM-41 and silica aerogel to investigate the effect of nanosizing towards the hydrogen storage properties of HB. Different loading of HB to the porous supports were investigated and optimized. The optimized loading of HB in MCM-41 and silica aerogel was 1:1 and 0.25:1, respectively. Both confined samples demonstrated great suppression of melting induced sample foaming. However, by-products formation was enhanced over dehydrogenation in an open system decomposition owing to the presence of extensive Si-O···BH3(HB) coordination that further promote the B-N bond cleavage to release N2H4. The Si-OH···N(N2H4) hydrogen bonding may further promote N-N bond cleavage in the resulting N2H4, facilitating the formation of NH3. As temperature increases, the remaining N-N-B oligomeric chains in the porous silica, which are lacking the long-range structure may further undergo intramolecular B-N or N-N cleavage to release substantial amount of N2H4 or NH3. Besides open system decomposition, we also reported a closed system decomposition where complete utilization of the N-H from the released N2H4 and NH3 in the secondary reaction can be achieved, releasing mainly hydrogen upon being heated up to high temperatures. Nanosizing of HB particles via PMMA encapsulation was also attempted. Despite the ester functional group that may favor multiple coordination with HB molecules, these interactions did not impart significant change towards the decomposition of HB selectively towards dehydrogenation.

Structural stability, dihydrogen bonding, and pressure-induced polymorphic transformations in hydrazine borane.

Hydrazine borane (N2H4BH3) has attracted considerable interest as a promising solid-state hydrogen storage material owing to its high hydrogen content and easy preparation. In this work, pressure-induced phase transitions of N2H4BH3 were investigated using a combination of vibrational spectroscopy, X-ray diffraction, and density functional theory (DFT) up to 30 GPa. Our results showed that N2H4BH3 exhibits remarkable structural stability in a very broad pressure region up to 15 GPa, and then two phase transitions were identified: the first one is from the ambient-pressure Pbcn phase to a Pbca phase near 15 GPa; the second is from the Pbca phase to a Pccn phase near 25 GPa. As revealed by DFT calculations, the unusual stability of N2H4BH3 and the late phase transformations were attributed to the pressure-mediated evolutions of dihydrogen bonding frameworks, the compressibility and the enthalpies of the high-pressure polymorphs. Our findings provide new insight into the structures and bonding properties of N2H4BH3 that are important for hydrogen storage applications.

Direct hydrazine borane fuel cells using non-noble carbon-supported polypyrrole cobalt hydroxide as an anode catalyst

Direct liquid fuel cells feeding on hydrazine borane (N2H4BH3), with C-PPY-Co(OH)2 as the anode catalyst and a Ni foam as the diffusion layer, achieve an open circuit voltage of 1.201 V and a peak power density of 60 mW cm−2.

Efficient and complete dehydrogenation of hydrazine borane over a CoPt catalyst.

Bimetallic CoPt alloy nanoparticles (NPs) immobilized on CeO2 nanorods (CoPt/CeO2) were synthesized by a facile wet-chemistry reduction method, which showed the highest catalytic efficiency reported to date for the complete dehydrogenation of hydrazine borane with a high TOF value of up to 5454 h-1 at 323 K.

Highly efficient dehydrogenation of hydrazine borane over CoIr/TiO2 catalyst

In recent years, hydrazine borane (HB) as an excellent hydrogen material has been extensively studied by researchers because of its substantial hydrogen content (15.4 wt%), favourable chemical stability, eco-friendliness and being easy to synthesize. With Higher activity, catalysts of HB dehydrogenation will undoubtedly be more desirable for practical applications. In this work, CoIr nanoparticles (NPs) are successfully immobilized on TiO2 substrate, achieving outstanding catalytic performance and 100% conversion for HB dehydrogenation. Particularly, Co0.6Ir0.4/TiO2 can complete the reaction for HB dehydrogenation at 323 K within 32 s (0.53 min), and shows a fairly high turnover frequency (TOF) value (5625 h−1), which is higher than the values achieved by most Ni-based catalysts reported so far in the same condition. This superior catalytic performance can be attributed to uniform dispersion of metal NPs with small size and strong interaction among the CoIr NPs and the substrate. It is unquestionable that our work will help to promote the use of HB as a promising hydrogen storage material for fuel cells.

Defects engineering of metal-organic framework immobilized Ni-La(OH)3 nanoparticles for enhanced hydrogen production

The development of low-cost, efficient, and durable catalysts to boost hydrogen production from hydrous hydrazine (N2H4·H2O) and hydrazine borane (N2H4BH3) is critical, but still a huge challenge. Herein, for the first time, noble-metal-free La(OH)3-doped Ni nanoparticles (NPs) supported on defect-rich metal−organic framework were constructed via a facile, green, and low-cost wet-chemical method. It is first found that the number of defects in MIL-125(Ti) can be easily regulated by a simple but efficient method. As a result, the defect-rich MIL-125-supported Ni-La(OH)3 catalyst shows superior catalytic activity, 100 % H2 selectivity, and robust durability for N2H4·H2O dehydrogenation with NaOH at 343 K, providing a turnover frequency (TOF) value high up to 870 h−1, surpassing all the non-noble metal catalysts reported so far and even outperforming some noble metal-containing catalysts. Interestingly, the catalyst also shows excellent catalytic efficiency for hydrogen production from N2H4BH3 with a TOF value as high as 2381 h−1 at 343 K. The superior catalytic efficiency is mainly due to the existence of abundant defective MIL-125, electron-rich, good dispersed and small Ni NPs, as well as the synergistic effect between metal and support. This work delivers inspiration in defect engineering and provides a promising strategy for rationally designing high-efficiency MOFs-based catalysts for hydrogen generation and other heterogeneous catalysis.

MIL-101 supported CeOx-modified NiPt nanoparticles as a highly efficient catalyst toward complete dehydrogenation of hydrazine borane

Low-cost Ni0.9Pt0.1–CeOx/MIL-101 achieved outstanding catalytic activity with a TOF value of 2951.1 h−1 at 323 K for hydrazine borane dehydrogenation.