Hydrolysis Of Ammonia Borane Research Articles

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.

Modulating Electronic Metal-Support Interactions to Boost Visible-Light-Driven Hydrolysis of Ammonia Borane: Nickel-Platinum Nanoparticles Supported on Phosphorus-Doped Titania.

Ammonia borane (AB) is a promising material for chemical H2 storage owing to its high H2 density (up to 19.6 wt %). However, the development of an efficient catalyst for driving H2 evolution through AB hydrolysis remains challenging. Therefore, a visible-light-driven strategy for generating H2 through AB hydrolysis was implemented in this study using Ni-Pt nanoparticles supported on phosphorus-doped TiO2 (Ni-Pt/P-TiO2 ) as photocatalysts. Through surface engineering, P-TiO2 was prepared by phytic-acid-assisted phosphorization and then employed as an ideal support for immobilizing Ni-Pt nanoparticles via a facile co-reduction strategy. Under visible-light irradiation at 283 K, Ni40 Pt60 /P-TiO2 exhibited improved recyclability and a high turnover frequency of 967.8 mol molPt -1 min-1 . Characterization experiments and density functional theory calculations indicated that the enhanced performance of Ni40 Pt60 /P-TiO2 originated from a combination of the Ni-Pt alloying effect, the Mott-Schottky junction at the metal-semiconductor interface, and strong metal-support interactions. These findings not only underscore the benefits of utilizing multipronged effects to construct highly active AB-hydrolyzing catalysts, but also pave a path toward designing high-performance catalysts by surface engineering to modulate the electronic metal-support interactions for other visible-light-induced reactions.

Self-Supported Pt@Ni2P for Controllable Hydrogen Release from Ammonia-Borane Hydrolysis

Self-Supported Pt@Ni₂P for Controllable Hydrogen Release from Ammonia-Borane Hydrolysis

ZIF-67 template-assisted porous carbon based Ru-Co synergistic effect for efficient NH3BH3 hydrolysis & 4-nitrophenol reduction: Effect of morphology and pore structure adjustment

Herein, dodecahedron, concave cube with a cavity and leaf-like ZIF were prepared through water hydrogen bond induced coordination structure engineering. MOF-derived C materials, with feature of generally maintained ZIF morphology, adjustable mesoporous structure and in situ N doping, were constructed with simple pyrolysis under N2 and phosphoric acid etching strategies. Ru loaded ZIF template-assisted mesoporous carbon materials were utilized for the ammonia borane hydrolysis and p-nitrophenol reduction. Up to 1031 min−1 TOF in ammonia borane hydrolysis and as high as 1.602 min−1p-nitrophenol reduction efficiency could be achieved over Ru loaded dodecahedron ZIF-67 template-assisted mesoporous carbon. Above excellent catalytic performance should be ascribed to the partial retained coordination structure engineering based catalytic active center optimization, the phosphoric acid etching assisted mesoporous structure construction for hydrophilicity and mass transfer promotion, as well as the Ru–Co synergistic structure induced charge transfer improvement.

Rattle-structured CuO/Co3O4@C microspheres, a potent bifunctional catalyst for hydrogen production from ammonia borane hydrolysis and methanolysis

Engineering and fabricating cost-effective and high-performing bifunctional catalysts for ammonia borane (AB) hydrolysis and methanolysis is paramount for their commercial availability. A series of rattle-structured CuO/Co3O4@C microsphere bifunctional catalysts for AB hydrolysis and methanolysis were produced using a simple hard template etching approach. The CuO/Co3O4@C-4 (4 refers to designed the mole ratio of Cu/Co) exhibits the best activity with TOF of 18.8 and 26.8 molH2·molcat-1·min−1 for AB hydrolysis and methanolysis, respectively. It is discovered that the excellent performance is mainly attributed to its unique rattle structure and the synergetic effect between Co3O4 and CuO. Kinetic isotope effect (KIE) experiments and infrared spectroscopy were applied to investigate AB hydrolysis and methanolysis reaction mechanisms. A suggested mechanism for AB methanolysis on rattle-structured CuO/Co3O4@C-4 is proposed based on the experiment results. This work could provide useful guidance for the construction of high-performance bifunctional catalysts for AB hydrolysis and methanolysis for hydrogen production.

Insights into boosting catalytic hydrogen evolution over Co doping Ru nanoparticles

Accurate regulation of surface chemical state on catalysts is crucial for achieving efficient performance but remains a major challenge. In this work, the lattice strain, d electronic state and ensemble effect of supported Ru catalysts are tuned via Co doping to boost the hydrogen evolution from ammonia borane (AB) hydrolysis. The optimized Ru0.6Co0.4/P25 composite displays outstanding catalytic performance with a turnover frequency of 443.7 min−1 in the absence of strong alkali. Experimental analysis and theoretical simulation reveal the boosting effect of RuCo alloy on the activation of AB originating from the compressed lattice strain, reduced d-band center of Ru via Co doping. The ensemble effect on optimized surface state leads to a bimolecular activation of H2O on Co atoms and AB on Ru atoms. Suitable adsorption strength of H* intermediates and reduced energy barrier of H2O dissociation induced by the electron interaction between Ru and Co atoms are responsible for the prominent catalytic activity over RuCo alloy. This research provides new insights into the catalytic mechanism and inspiration for the rational design of heterogeneous catalysts and energy storage materials.

MCM-41 supported NiPCeOx nanoparticles as highly efficient non-noble metal catalyst for hydrolytic dehydrogenation of ammonia borane

Efficient and controllable hydrogen release from ammonia borane (NH3BH3, AB) hydrolysis is a secure and effective way to generate hydrogen on-demand. The development of high-efficiency and low-cost catalysts is of important but still remains a great challenge. Herein, uniformly dispersed NiPCeOx nanoparticles (NPs) with narrow size distribution supported on mesoporous MCM-41 were prepared by incipient wetness impregnation followed by NaBH4 reduction. Attributing to the ordered mesoporous structure of the support as well as the efficiently enhancement of electron density on the Ni active sites brought by the electron transfers, the NiPCeOx/MCM-41 catalyst exhibits exceptional catalytic performance towards AB hydrolysis with a high turnover frequency (TOF) value of 47.3 molH2(molNi·min)−1 at 298 K and a low apparent activation energy (Ea) of 35.86 kJ mol−1. Furthermore, the NiPCeOx/MCM-41 catalyst shows excellent durability with 76.5% of the initial TOF value remained after five cycles.

Facile construction of robust Ru-Co3O4 Mott-Schottky catalyst enabling efficient dehydrogenation of ammonia borane for hydrogen generation

Developing efficient catalysts for the dehydrogenation of ammonia borane (AB) is important for the safe storage and controlled release of hydrogen, but it is a challenging task. In this study, we designed a robust Ru-Co3O4 catalyst using the Mott-Schottky effect to induce favorable charge rearrangement. The self-created electron-rich Co3O4 and electron-deficient Ru sites at heterointerfaces are indispensable for the activation of the B-H bond in NH3BH3 and the OH bond in H2O, respectively. The synergistic electronic interaction between the electron-rich Co3O4 and electron-deficient Ru sites at the heterointerfaces resulted in an optimal Ru-Co3O4 heterostructure that exhibited outstanding catalytic activity for the hydrolysis of AB in the presence of NaOH. The heterostructure had an extremely high hydrogen generation rate (HGR) of 12238 mL min−1 gcat-1 and an expected high turnover frequency (TOF) of 755 molH2 molRu-1 min−1 at 298 K. The activation energy needed for the hydrolysis was low (36.65 kJ mol−1). This study opens up a new avenue for the rational design of high-performance catalysts for AB dehydrogenation based on the Mott-Schottky effect.

Hydrogen Production from Ammonia Borane Hydrolysis Catalyzed by Metal Oxide-Based Materials

Hydrogen Production from Ammonia Borane Hydrolysis Catalyzed by Metal Oxide-Based Materials

Recent Advances and Perspectives on Supported Catalysts for Heterogeneous Hydrogen Production from Ammonia Borane.

Ammonia borane (AB), a liquid hydrogen storage material, has attracted increasing attention for hydrogen utilization because of its high hydrogen content. However, the slow kinetics of AB hydrolysis and the indefinite catalytic mechanism remain significant problems for its large-scale practical application. Thus, the development of efficient AB hydrolysis catalysts and the determination of their catalytic mechanisms are significant and urgent. A summary of the preparation process and structural characteristics of various supported catalysts is presented in this paper, including graphite, metal-organic frameworks (MOFs), metal oxides, carbon nitride (CN), molybdenum carbide (MoC), carbon nanotubes (CNTs), boron nitride (h-BN), zeolites, carbon dots (CDs), and metal carbide and nitride (MXene). In addition, the relationship between the electronic structure and catalytic performance is discussed to ascertain the actual active sites in the catalytic process. The mechanism of AB hydrolysis catalysis is systematically discussed, and possible catalytic paths are summarized to provide theoretical considerations for the designing of efficient AB hydrolysis catalysts. Furthermore, three methods for stimulating AB from dehydrogenation by-products and the design of possible hydrogen product-regeneration systems are summarized. Finally, the remaining challenges and future research directions for the effective development of AB catalysts are discussed.

Hierarchical Co3O4/SAPO-34 supported PtCo bimetallic nanoparticles as highly efficient catalyst for hydrogen generation from ammonia borane hydrolysis

Hierarchical Co3O4/SAPO-34 supported PtCo bimetallic nanoparticles (NPs) with uniform dispersion and narrow size-distribution were prepared for the hydrolysis of AB to produce hydrogen. Strategies including the sequential impregnation of cobalt and platinum precursors followed by partial reduction were employed to anchor Pt NPs. Befitting from the interfacial interaction between Co and Co3O4 NPs, the intermetallic synergistic effect of PtCo NPs and the synergistic interaction between Co NPs and SAPO-34 zeolite, the prepared Pt@Co/Co3O4/SP-10(400,2) catalyst exhibited outstanding catalytic activity with a high turnover frequency (TOF) value of 314 molH2(molPt·min)-1 at 303 K. In addition, the flake-assemble hierarchical structure of SAPO-34 played an important role in improving the dispersion of metal NPs and the mass transfer rate between reactants and active sites.

Regulating the electronic structure of Pd nanoparticles through metal alloy–support interactions for enhanced hydrogen generation

Regulating the electronic structure of noble metals through metal alloy–support interactions is significant for hydrogen economy. Herein, a PdAg alloy highly dispersed on the surface of Ti3C2 is successfully designed through a simple microwave-assisted reduction method. The catalytic activity of PdAg alloys with various molar ratios manifests obviously enhanced catalytic activity compared to monometallic catalysts toward hydrogen generation in ammonia borane (AB) hydrolysis. Specifically, Pd4Ag1/Ti3C2 presents an optimal turnover frequency (TOF) value of 1296 min−1 at room temperature and a lower activation energy (Ea) of 38.8 kJ mol-1. Through the experimental results, the formation of a PdAg alloy with the introduction of the second metal Ag adjusts the electronic structure around Pd and enhances the catalytic activity. Additionally, the metal alloy–support interaction between Ti3C2 and the PdAg alloy significantly promotes hydrogen generation during the hydrolysis of AB. This study provides new ideas and a reasonable basis for heterogeneous catalysis based on bimetallic catalysts.

Water State-Driven Catalytic Hydrolysis of Ammonia Borane on Cu3P-Carbon Dot-Cu Composite.

Hydrogen production from ammonia borane (AB) is usually governed by water activation, which is not only energy-intensive but also requires expensive and complicated catalysts. We here propose an integrated photocatalytic-photothermal system that dramatically improves water activation and lowers the transport resistance of H2 by means of intermediate state water evaporation. This system is constructed by covering nanocomposites (Cu3P-carbon dots-Cu) upon vertically aligned acetate fibers (VAAFs). As a result of superior hydration effect of VAAFs and local photothermal heating for rapid water evaporation, its hydrogen production efficiency from AB hydrolysis reaches over 10 times the particulate suspension system under solar irradiation. Mechanism analysis reveals that the rapid vaporization of intermediate water promotes the cleavages of O-H bonds in bound water and the adsorption reaction of AB and water molecules at active sites. Therefore, this work provides a novel approach to optimize catalytic reaction in thermodynamics and kinetics for the hydrolysis of AB.

Halloysite-based aerogels for efficient encapsulation of phase change materials with excellent solar energy storage and retrieval performance

Developing low-cost composite phase change materials with good shape stability, excellent mechanical strength, high thermal conductivity, large encapsulation ratio, strong light absorption and eminent solar-to-thermal conversion capacity is of great challenge to solve the scaling-up related issues of organic solid–liquid phase change materials during the utilization of solar energy. In this work, halloysite/poly(vinyl alcohol) and halloysite/poly(vinyl alcohol)/reduced graphene oxide aerogels with rich three-dimensional honeycomb structure were prepared by a freezing and freeze-drying method, which can significantly promote the encapsulation ratio of lauric acid in the pores of both aerogels and halloysite nanotube. Halloysite nanotube with high aspect ratio can improve the compressive strength of the aerogels and shape stability of the composite phase change materials, while reduced graphene oxide can reinforce the thermal conductivity and light absorption ability. After encapsulation of lauric acid, the halloysite/poly(vinyl alcohol) 9:1 and halloysite/poly(vinyl alcohol)/reduced graphene oxide 9:1 phase change composites demonstrate extraordinarily high latent heat of 195.4 J/g and 197.0 J/g, respectively, leading to high encapsulation ratios of 97.2 % and 98.1 % respectively, accompanied by good chemical and thermal stability over 300 thermal cycles. The thermal conductivity of lauric acid@halloysite/poly(vinyl alcohol)/reduced graphene oxide is remarkably elevated to 0.343 W/m∙K, exceeding 39.4 % that of pure lauric acid (0.246 W/m∙K). Besides, the lauric acid@halloysite/poly(vinyl alcohol)/reduced graphene oxide realizes a conspicuous solar-to-thermal conversion with solar absorption capacity of 95 % throughout the full spectrum of solar light. The marvelous improvement in the solar-to-thermal conversion efficiency can be attributed to thermally conductive interconnected network of halloysite nanotube and reduced graphene oxide. Thus, lauric acid@halloysite/poly(vinyl alcohol)/reduced graphene oxide and lauric acid@halloysite/poly(vinyl alcohol) are tentatively used in the catalytic hydrolysis of ammonia borane, and they can efficiently harvest, convert and store solar energy in the form of thermal energy and release it for the reaction, which obviously accelerates the extent of reaction with turnover frequency increasing from 29.50 (molH2/molcatalyst·min) at 25 °C to 59.18 and 41.74 (molH2/molcatalyst·min) under the heating of solar energy stored lauric acid@halloysite/poly(vinyl alcohol)/reduced graphene oxide and lauric acid@halloysite/poly(vinyl alcohol), respectively. This work paves a way for fabricating halloysite-based aerogel and composite phase change materials for thermal/solar energy saving application.

Mitigation of polyborate precipitation on Pd/Fe2O3 sites during ammonia borane hydrolysis: An alternate insight into the role of oxygen vacancies

Understanding the stability of catalysts is essential for both fundamental science and industrial process design. Herein, we show that oxygen vacancies at the interfaces of Pd/Fe2O3 catalysts prevent the precipitation of polyborate byproducts on the catalyst's surface during ammonia borane (AB) hydrolysis, thereby enhancing the catalyst's stability. Fe2O3-supported Pd nanoparticles were synthesized by a solid-state approach wherein Fe2O3 support size was varied as 20 nm, 45 nm, and 70 nm while the Pd content was maintained at 5% by wt. With increasing cycles, the catalyst containing 20 nm Fe2O3 nanoparticle support is stable, while the catalysts with 45 and 70 nm Fe2O3 supports showed deterioration of catalytic activity. In lower support sizes, due to the fine dispersion of Pd, in-situ oxygen vacancies are created at Pd/Fe2O3 interface during AB hydrolysis. We propose that more water molecules congregate at the vacancy sites, which aids the solubility of polyborates, thereby extending the activity of the catalyst through multiple cycles.

Gamma-ray-irradiated construction of CuCo-based nanocomposites for attractive hydrogen production and tandem hydrogenation

Nitroarenes are important chemicals but display toxity to environment and organisms. In the present work, non-precious bicomponent CuCo-based nanocomposites (CuCo2O4/CuO) prepared with the aid of gamma(γ)-ray-irradiation were utilized for hydrogen production from ammonia borane (AB) hydrolysis and tandem hydrogenation of nitroarenes. The γ-ray-irradiation remarkably boosted the catalytic performance for the AB dehydrogenation and the hydrogenation of nitroarenes. Hydrogen generation rate (HGR) for the CuCo2O4/CuO catalyst reached 856.3 mL min−1·gcat−1, which was approximately two-fold than that of the catalyst prepared by conventional method (only 397.1 mL min−1·gcat−1). Meanwhile, this irradiation-induced catalyst also showed excellent performance for the hydrogenation of screened nitroarenes with 100% yield of the corresponding amines. The CuCo2O4/CuO catalyst exhibited high reusability with ∼90% remained activity of the initial one after six runs. The bicomponent CuCo2O4/CuO exhibited positive hydrogen spillover and synergistic effects contributing to the considerable activity improvement, which is beneficial to the detoxication, conversion and utilization of poison nitroarenes.

Fabrication of multiatomic structure of Cu-CoO/Co interface for efficient hydrogen generation from ammonia borane hydrolysis

Hydrogen generation from hydrolysis of ammonia borane is a secure and promising route for conversion of hydrogen energy. Preparation of efficient and economical catalysts is highly required for the development hydrogen economy. In this study, the Co-based catalysts with multiatomic structure were designed for hydrolysis of ammonia borane reaction. The synergistic effect between Co and M (M = Cu, Ni, Fe) greatly enhanced the catalytic performance of bimetallic catalysts. The TOF value of CoCu-NC-5 towards 8.12 min−1 is 7 times that of the single Co catalyst. Moreover, The CoCu catalysts showed the stronger synergistic effect and highest catalytic activity for hydrogen generation, compared with CoNi and CoFe catalysts. The TOF value of CoCu-NC-5 is 2.3 and 6.0 times that of CoFe-NC-5 and CoNi-NC-5 catalysts, respectively. The active component structure of Cu-CoO/Co interface in CoCu-NC-5 is beneficial for activation and dissociation of water molecule due to the strong electron transfer effect and positive synergy. The activation energy over CoCu-NC-5 is 34.25 kJ mol−1, and the catalyst exhibited good stability. This work provides a feasible method for rational design of efficient catalysts with hierarchical structure for conversion of energy.

Increasing the catalytic efficiency of rhodium(0) nanoparticles in hydrolytic dehydrogenation of ammonia borane

It reviews the papers reporting on the use of rhodium nanocatalysts in hydrogen generation from the hydrolysis of ammonia borane in the following groups: (i) water soluble rhodium complexes, (ii) colloidal nanoparticles of rhodium, (iii) rhodium(0) nanoparticles supported on carbonaceous materials such as activated carbon, graphene, carbon nanotubes, (iv) the use of oxide supports for rhodium(0) nanoparticles, (v) the use of magnetic powders as support for rhodium(0) nanoparticles to make them magnetically recoverable. In each group, the reported results are evaluated by considering the increase in the catalytic activity (specifically measured in turnover frequency), the stability and durability, the lifetime (that is, how long the nanocatalyst can be used in releasing hydrogen gas from the hydrolysis of ammonia borane at appreciable rate), reusability (that is, how many times the catalyst can be isolated and reused for the same hydrolysis reaction generating hydrogen at acceptable rate). Overall, the work reported in each of the papers is evaluated in terms of contribution to the catalytic efficiency of rhodium nanocatalysts in hydrogen generation from the hydrolysis of ammonia borane at room temperature. At the end, conclusions and suggestions are given how to increase the overall catalytic efficacy of the precious rhodium nanocatalysts in hydrolytic dehydrogenation of ammonia borane.

Pt@Ni2P/C3N4 for charge acceleration to promote hydrogen evolution from ammonia-borane

Incorporating g-C3N4 with transition metal phosphides is emerging as a low-cost and robust co-catalyst for hydrogen evolution. The ammonia borane hydrolysis is an efficient method to release H2 at ambient conditions in the presence of a catalyst. An efficient and cheap catalyst is needed for practical application to achieve this benchmark. For this purpose, a catalyst Ni2P/C3N4 is synthesized by hydrothermal method and low-temperature phosphidation. The optimization reveals that the Ni2P/C3N4 with 6.5% Ni contents shows the best performance for H2 release. Furthermore, 2% Pt nanoparticles loading over Ni2P/C3N4 boosts the charge transfer and improves activity 5.7-fold compared to Ni2P/C3N4, and the Pt-loaded catalyst is depicted as Pt@Ni2P/C3N4. The reaction kinetics reveals that the hydrogen evolution rate accelerates by increasing the amount of Pt@Ni2P/C3N4 and AB concentration, and the loading of Pt nanoparticles loaded over Ni2P/C3N4 reduces the activation energy significantly. Moreover, the ionic interaction between Pt and Ni2P/C3N4 generates Ptᵟ+ and (Ni2P/C3N4)ᵟ− active sites which facilitates B–H cleavage and O–H bonds of ammonia borane and water, respectively. Incorporating transition metals phosphide and noble metals supported over g-C3N4 paves the pathway toward the efficient H2 evolution from ammonia borane, bringing cost-effective modifications to synthesize constructive catalysts.

A facile preparation of graphene hydrogel-supported bimetallic RuM (M: Co, Ni, Cu) nanoparticles as catalysts in the hydrogen generation from ammonia borane

Abstract The synthesis of ultrafine well-dispersed bimetallic RuM (M: Co, Ni, Cu) nanoparticles (NPs) supported on graphene hydrogel (GH) was accomplished by a novel one-pot wet-chemical protocol that comprised the hydrothermal reduction of the mixture of graphene oxide and metal precursors by ethylene glycol (EG) in a Teflon-coated stainless-steel reactor at 180 °C. In this study, for the first time, we report the synthesis of bimetallic RuM NPs anchored on GH during the hydrothermal production of GH from graphene oxide (GH-RuM) and the catalysis of the yielded GH-Ru in the hydrolysis of ammonia borane (AB). As-synthesized GH-RuM (M: Co, Ni, Cu) nanocatalysts were characterized by using many advanced instrumental techniques including TEM, XRD, XPS, and ICP-MS. The bimetallic catalysts denoted as GH-Ru20Co80, GH-Ru30Ni70 and GH-Ru10Cu90 exhibited much higher catalytic activity compared to their Ru, Co, Ni and Cu monometallic counterparts in the hydrolytic dehydrogenation of AB. The catalytic performance of as-prepared NPs in terms of hydrogen generation rate (HGR) was achieved in the order of RuCo > RuNi > RuCu and the highest HGR calculated for the catalyst GH-Ru20Co80 reached 8911.5 mL H2 gcat −1 min−1 at room temperature with an activation energy of 52.5 kJ mol−1.