Hydrolysis Of Ammonia Borane Research Articles

Bimetallic NiCo Nanoparticles Embedded in Organic Group Functionalized Mesoporous Silica for Efficient Hydrogen Production from Ammonia Borane Hydrolysis

In this study, bimetallic NiCo nanoparticles (NPs) were encapsulated within the mesopores of carboxylic acid functionalized mesoporous silica (CMS) through the chemical reduction approach. Both NaBH4 and NH3BH3 were used as reducing agents to reduce the metal ions simultaneously. The resulting composite was used as a catalyst for hydrolysis of ammonia borane (NH3BH3, AB) to produce H2. The bimetallic NiCo NPs supported on carboxylic group functionalized mesoporous silica, referred to as NixCo100−x@CMS, exhibited significantly higher catalytic activity for AB hydrolysis compared to their monometallic counterparts. The remarkable activity of NixCo100−x@CMS could be ascribed to the synergistic contributions of Ni and Co, redox reaction during the hydrolysis, and the fine-tuned electronic structure. The catalytic performance of the NixCo100−x@CMS nanocatalyst was observed to be dependent on the composition of Ni and Co. Among all the compositions investigated, Ni40Co60@CMS demonstrated the highest catalytic activity, with a turn over frequency (TOF) of 18.95 molH2min−1molcatalyst−1 and H2 production rate of 8.0 L min−1g−1. The activity of Ni40Co60@CMS was approximately three times greater than that of Ni@CMS and about two times that of Co@CMS. The superior activity of Ni40Co60@CMS was attributed to its finely-tuned electronic structure, resulting from the electron transfer of Ni to Co. Furthermore, the nanocatalyst exhibited excellent durability, as the carboxylate group in the support provided a strong metal–support interaction, securely anchoring the NPs within the mesopores, preventing both agglomeration and leakage.

Bimetallic (Co/Ni) MOF-Derived CoNiP Hierarchically Porous Carbon Monolithic Aerogel for the Hydrolysis of Ammonia Borane

Bimetallic (Co/Ni) MOF-Derived CoNiP Hierarchically Porous Carbon Monolithic Aerogel for the Hydrolysis of Ammonia Borane

Recent Progress on Cobalt‐Based Heterogeneous Catalysts for Hydrogen Production from Ammonia Borane

AbstractAmmonia borane (NH3BH3, AB) is a quintessential exemplar of chemical hydrogen storage materials and has been widely used in hydrogen evolution. Although expensive metal catalysts (such as Rh, Ru, Pt, Ag, etc.) exhibit high activity in the hydrolysis of ammonia borane, inexpensive metals are more economical. Cobalt (Co), in particular, is not only relatively inexpensive and readily available, but also possesses high activity and selectivity. Compared to other catalysts, cobalt‐based catalysts have better durability and can maintain catalytic activity for a longer period of time, making them favored by researchers. These catalysts demonstrate excellent stability, hydrogen evolution rate, and turn over frequency. This article summarized previous progress in low price metal cobalt‐based catalysts for hydrogen precipitation from ammonia borane, focusing on cobalt‐based catalysts supported on various supports, especially those supported on carbon materials, metal oxides, MOFs, and nickel foams. The characteristics of high‐performance catalytic systems are analyzed in detail. The development prospects of Co catalysts for hydrogen production from ammonia borane were also discussed. In summary, this review compiles various supported and other types of cobalt based catalysts in recent years, and also identifies the existing problems with these catalysts, providing a reference for developers to study these catalysts. It is believed that through careful regulation of the electronic and spatial structures of Co based catalysts, well‐designed Co based non precious metal catalysts will play a significant role in the decomposition of ammonia borane.

Ruthenium-Based High-Entropy Alloys Expediting Hydrogen Evolution through Catalytic Hydrolysis of Ammonia Borane

Ruthenium-Based High-Entropy Alloys Expediting Hydrogen Evolution through Catalytic Hydrolysis of Ammonia Borane

Restructuring the interfacial active sites to generalize the volcano curves for platinum-cobalt synergistic catalysis

Computationally derived volcano curve has become the gold standard in catalysis, whose practical application usually relies on empirical interpretations of composition or size effects by the identical active site assumption. Here, we present a proof-of-concept study on disclosing both the support- and adsorbate-induced restructuring of Pt-Co bimetallic catalysts, and the related interplays among different interfacial sites to propose the synergy-dependent volcano curves. Multiple characterizations, isotopic kinetic investigations, and multiscale simulations unravel that the progressive incorporation of Co into Pt catalysts, driven by strong Pt-C bonding (metal-support interfaces) and Co-O bonding (metal-adsorbate interfaces), initiates the formation of Pt-rich alloys accompanied by isolated Co species, then Co segregation to epitaxial CoOx overlayers and adjacent Co3O4 clusters, and ultimately structural collapse into amorphous alloys. Accordingly, three distinct synergies, involving lattice oxygen redox from Pt-Co alloy/Co3O4 clusters, dual-active sites engineering via Pt-rich alloy/CoOx overlayer, and electron coupling within exposed alloy, are identified and quantified for CO oxidation (gas-phase), ammonia borane hydrolysis (liquid-phase), and hydrogen evolution reaction (electrocatalysis), respectively. The resultant synergy-dependent volcano curves represent an advancement over traditional composition-/size-dependent ones, serving as a bridge between theoretical models and experimental observations in bimetallic catalysis.

N, P self-mixing microporous carbon supported RuCo alloys for “on–off” control H2 generation from ammonia borane

Significant advancements have been made in the field of metal nanocatalysts for hydrogen (H2) release from ammonia borane (AB) hydrolysis. However, challenges persist in enhancing the rate of H2 release and the stability of materials through precise regulation of atom utilization in supported metal nanocatalysts. In this study, a self-mixed microporous carbon carrier (NPC) containing nitrogen (N) and phosphorus (P)was synthesized by activating adenosine triphosphate disodium (ATP), thereby eliminating the need for additional N and P sources. The synergistic effect of pore capture and N and P anchoring facilitated the successful preparation of RuCo alloys on the ATP-derived carbon support. Benefiting from the alloy effect of Ru and Co, the developed Ru1Co9/NPC catalyst achieved optimal catalytic performance, with a turnover frequency of 747.75 min−1, as well as favorable reusability for H2 release from AB. Furthermore, the incorporation of Zn2+ and EDTA-2Na enable control over the “ON-OFF” switch of AB as needed. This research not only presents a novel and efficient nanoalloy catalyst for AB hydrolysis but also establishes a viable method for on-demand H2 production.

Pt–Ni–Co trimetallic nanoparticles anchored on graphene oxide: An effective catalyst for ammonia-borane hydrolysis and direct electrooxidation of ammonia-borane in alkaline solution

In this study, graphene oxide supported platin, nickel and cobalt trimetallic nanoparticles (PtNiCo@GO) were prepared by the impregnation/reduction method. The catalytic performances of PtNiCo@GO catalysts prepared with different atomic ratios were investigated for hydrogen production and electro-oxidation of ammonia-borane (AB). For hydrolysis of ammonia-borane, Pt0.8Ni0.1Co0.1@GO catalyst exhibited higher catalytic activity than Pt0.6Ni0.2Co0.2@GO, Pt0.4Ni0.3Co0.3@GO, and Pt0.2Ni0.4Co0.4@GO. The hydrogen generation rate and turnover frequency values were found to be 540 mL min−1g−1 and 42.8 min−1, respectively, in the experiment conducted at 35 °C, 0.5 mmol AB, and 50 mg Pt0.8Ni0.1Co0.1@GO catalyst. The activation parameters (Ea, ΔH#, and ΔS#) in the catalytic hydrolysis of AB were obtained at 42.22 kJ/mol, 31.95 kJ/mol and −114.82 J/(mol × K), respectively. The effects of the PtNiCo@GO catalyst on AB electro-oxidation were made at a scanning rate of 100 mV/s in the potential range of - 1V/+1V against Ag/AgCl, and chronoamperometry measurements were made at constant potentials of - 0.2V, 0.1V and 0.4V. For cyclic voltammetry and chronoamperometry measurements, 5 mM [Fe(CN)6]3/4 (1 M KCl) redox probe and 1 M NaOH + 50 mM AB solution were used.

Fabrication of Gold and Silver Nanoparticles Supported on Zinc Imidazolate Metal-Organic Frameworks as Active Catalysts for Hydrogen Release from Ammonia Borane.

Well-dispersed Au and Ag nanoparticles (NPs) have been immobilized on a zinc imidazolate metal-organic framework, Zn(mim), using the "one-pot" method and tested as catalysts in ammonia borane hydrolysis. The AuNPs@Zn(mim) and AgNPs@Zn(mim) materials were characterized by FTIR, XRD, ICP-OES, TGA, BET, SEM, and TEM. The AgNPs@Zn(mim) catalyst showed a high yield (98.5%) and high hydrogen generation rate (3352.71 mL min-1 gAg -1) in NH3BH3 dehydrogenation. The determined activation energies (19.6 kJ mol-1 for AuNPs@Zn(mim) and 38.13 kJ mol-1 for AgNPs@Zn(mim)) are lower than those for most reported catalysts containing Au/Ag-MOF used in the hydrolysis of NH3BH3. Moreover, the catalysts tested here revealed good stability and reusability, preserving 71.42% (AuNPs@Zn(mim)) and 88.23% (AgNPs@Zn(mim)) of their initial catalytic activities after five consecutive cycles. In the case of AgNPs@Zn(mim), the combination of the simple and green synthesis method, low active metal content, relatively low cost, and moderate dehydrogenation conditions makes the material an excellent candidate to produce hydrogen from ammonia borane.

Sub-2 nm Ternary Metallic Alloy Encapsulated within Montmorillonite Interlayers for Efficient Hydrogen Generation from Ammonia Borane Hydrolysis

Sub-2 nm Ternary Metallic Alloy Encapsulated within Montmorillonite Interlayers for Efficient Hydrogen Generation from Ammonia Borane Hydrolysis

Preparation of Co0.5Cu0.5/CNR catalyst and its performance in hydrogen production by hydrolysis of ammonia borane

Cobalt nitrate and copper nitrate was mixed to prepare solution A. Phenyldicarboxylic acid and N,N-dimethylformamide was mixed to prepare solution B. Co/Cu Lavashield skeleton series materials (Co/Cu-MIL precursors) was then synthesized by mixing the above two solution via solvothermal method. The precursor was further carbonized to produce the MOFs derivatives, i.e. bimetallic carbon nanorods (CoxCu1–x/CNR) catalysts. The morphology and composition of the catalysts were explored by SEM, TEM, XRD, XPS and other characterization means. The results showed that CoxCu1–x/CNR was successfully obtained after calcination of Co/Cu-MIL at high temperature. The activity of the catalyst was optimal when x=0.5, the solvothermal temperature of 120 °C and the calcination temperature of 650 °C. The TOF value of the Co0.5Cu0.5/CNR catalyst for the hydrolysis of ammonia borane for the production of hydrogen was 2718.21 h–1 with activation energy of 51.64 kJ/mol. The catalyst had good cyclic stability. Although the activity decreased, the conversion of AB still maintained 100% after 10 cycles.

Controllably hydrolytic dehydrogenation of NH3BH3 over micropore-dominant porous carbon confined RuPd ultrafine alloys

At present, controllable producing hydrogen from the catalytic hydrolysis of ammonia borane (AB, NH3BH3) is very meaningful and challenging. Therefore, developing an effective catalyst for the reaction, clarifying its catalytic mechanism, and realizing controllable hydrogen release are extremely indispensable. In this work, RuPd nanoalloys are evenly confined by the agricultural waste wheat straw-derived carbon (denoted as WSC) with a micropore-dominant porous structure and plentiful N/O doping. Attributing to the particular support effect of WSC and the interesting RuPd alloy effect, the as-prepared bimetallic catalysts provide encouraging catalytic performance in AB hydrolysis. Catalyzed by the optimal Ru0.50Pd0.50@WSC, the turnover frequency (TOF) and hydrogen evolution rate are 214.5 min−1 and 50800 mL min−1 g−1, respectively, and the apparent activation energy is only 23.2 kJ mol−1. Moreover, introducing proper NaOH (1.5 M) further accelerates hydrogen release (TOF = 502.8 min−1, specific rate = 119100 mL min−1 g−1). The isotope experiments depict a kinetic isotope effect of 2.85, evidencing the vital role of the hydrogen–oxygen bond scission in this catalytic reaction. More importantly, benefitting from the difference in adsorption energy and strong coordination ability, the “on–off” control for the hydrolysis of AB over Ru0.50Pd0.50@WSC can be realized with the Zn2+/EDTA2- system. This study provides an attractive metal alloy catalyst and some insights for the controllable hydrolysis of AB.

Fabrication of an In‐situ Synthesized Porous Silica‐Ruthenium‐Nickel Composite Catalyst for Hydrolysis of Ammonia Borane

AbstractThis work investigated in‐situ synthesis of porous silica‐nickel‐ruthenium composite catalysts for hydrolysis of ammonia borane. The precursors were prepared with an anionic surfactant, sodium dodecyl sulfate (SDS), to form porous structure in the precursor particles, and the precursors was treated in aqueous solution including sodium borohydride and ammonia borane for in‐situ process to parallelly activate and use the catalysts for hydrolysis of ammonia borane. The result of TEM and nitrogen sorption measurements suggested that the primary particle size of the in‐situ synthesized catalysts decrease with increasing the amount of SDS and sodium chloride as the additive for controlling the primary particle size probably because of the effect of sodium ions to inhibit nuclei growth of the primary particles. From the EDS analyses, the composition of active nickel and ruthenium contents increased with increasing the amount of SDS and sodium chloride except for the highest amount of SDS probably because of adsorption of the metal cations with the excess amount of the surfactant anion to decrease the amount of the metal cations including the catalyst. The in‐situ synthesized catalyst including small size primary particles and high nickel and ruthenium content tended to exhibit high activity for hydrolysis of ammonia borane.

Pt/facet-Engineered Hydroxyapatite Co-Catalyst for Highly Efficient Hydrolysis of Ammonia Borane

Ammonia borane (AB, NH3BH3) is a promising candidate for a hydrogen-storage material because of its high stability as a solid state at room temperature under atmospheric pressure. This study demonstrated a novel catalyst design for highly efficient hydrolysis of AB by hybridizing Pt catalyst with hydroxyapatite (HAp, Ca10(PO4)6(OH)2) as an “active support”, possessing Lewis-acidic Ca2+ sites in the a-plane and Lewis-basic PO43- sites in the c-plane. Facet-engineered HAp particles were synthesized via the microwave-assisted hydrothermal reaction using Ca-EDTA chelates. Varying the Ca/P ratio of HAp precursor (from 1.5 to 1.8) affected the particle morphology, exposed facet ratio of {300} to {002}, and the percentage of phosphate anion species (PO43- and HPO42-). The rod-like HAp sole catalysts performed approximately 2-fold higher activity for the hydrolysis of AB, compared with spherical HAp with low crystallinity. Moreover, the Pt/rod-like HAp co-catalyst demonstrated superior catalytic performance with a turnover frequency (TOF) of 623 molH2 molPt-1 min-1 than the Pt/spherical HAp (<232 molH2 molPt-1 min-1). We proposed a possible mechanism of a synergistic effect in the significant enhancement of the hydrogen release rate from AB. Lewis basic PO43- and Lewis acidic Ca2+ sites on HAp would affect preferential adsorption of electron-deficient BH3 and electron-rich NH3 groups in AB, catalyzing cleavage of B-N bonds. Besides, PO43- sites play a critical role in anchoring Pt particles towards electron transfer from Pt to PO43-, resulting in considerable enhancement of catalytic performance in dissociative adsorption of water molecules, which is a rate-determining step in the hydrolysis.Graphical

Delayed ammonia release of ammonia borane hydrolysis by citric acid

Ammonia borane (AB), with high hydrogen density and stability under ambient conditions, readily releases hydrogen via catalyzed hydrolysis. However, ammonia, a byproduct of hydrogen release, limits its utilization. Citric acid, a safe and cost-effective acid catalyst, for the acid catalyst of AB hydrolysis was investigated in this study to mitigate ammonia emissions while enhancing hydrogen release. Maximal hydrogen release (3 eq.H2) and ammonia emission suppression (<0.5 ppm) were achieved using a 2-mol/L AB aqueous solution adding into citric acid powder (molar ratio of AB: citric acid = 1:1). In contrast, the amount of hydrogen release at other concentrations and/or using the mixing method was below 2.7 mol/mol AB within several hours. Ammonia re-released even after hydrogen release in the case of high AB concentration (e.g. >4 mol/L AB aqueous solution with citric acid powder (molar ratio of AB: citric acid = 1:1)) in the solution because of formation of borate ester (1:2 borate–diol molar ratio) via mono-ammonium citrate (a borate-ester precursor), which was revealed by the solution NMR. These results reveal a cost-effective and simple on-way method for hydrogen release with suppressed impurities. Furthermore, understanding impurity generation mechanisms can contribute to utilizing AB-derived hydrogen.

Preparation of Ni0.6Cu0.4O/NC catalyst and its catalytic performance for hydrogen production from hydrolysis of ammonia borane

Ammonia borane (NH3BH3, AB) is an ideal feedstock with high hydrogen storage capacity. In this paper, nitrogen-containing carbon material (Ni0.6Cu0.4O/NC) catalyst was prepared by high-temperature carbonization of Ni/Cu-ZIF precursor under nitrogen atmosphere. The microstructure as well as the composition of the as-prepared catalyst were characterized. In addition, the catalytic performance of the catalyst was tested under reaction conditions. The results showed that the activation energy (Ea) for hydrolysis of AB over Ni0.6Cu0.4O/NC catalyst was 56.8 kJ/mol with TOF value as high as 1572.2 h–1. The hydrogen production could be approximated as a zero-order reaction with respect to the concentration of AB, and a one-order reaction with respect to the amount of catalyst. The catalyst still maintained good activity after ten cycles, indicating the good stability.

Spontaneous Emulsification of Organometallic Complexes Applied to the Synthesis of Nanocapsules Active for H2 Release from Ammonia-Borane.

Herein, we achieved spontaneous emulsification of organometallic precursors to elaborate subμm metal nanocapsules after interfacial reduction. Depending on the proportion of the three components, water, solvent, and the metal precursor, either thermodynamically stable "surfactant-free microemulsions" (SFME) or metastable Ouzo emulsions are formed. We investigated the catalytic transition metals Au, Pd, and Pt, individually or combined, and stabilized by various ligands. Upon reduction of the precursors, either shells of discrete nanoparticles (NPs) or continuous shells were obtained, for the SFME and Ouzo emulsions, respectively. The Au/Pd mixed emulsions lead to a unique structural morphology, in which the Au-Pd nanoparticles are embedded in a continuous submicronic metal shell. The AuNPs are available to grow larger particles within the NP shell using a seeded growth approach. The water-stable and surfactant-free nanocapsules are appealing as catalysts, and, as such, were evaluated for the hydrolysis of ammonia-borane as a promising catalytic strategy for H2 release from an H-high-content storage material. This work establishes for the first time a genuine activity of water-compatible gold colloids for this reaction.

Ternary Fe–Ni–B particles supported on Cu(OH)2–Cu foam: A highly efficient and stable catalyst for hydrolysis of ammonia borane

Ammonia borane (NH3BH3) as a solid chemical hydrogen storage material with a high hydrogen content can be hydrolyzed under mild conditions to release hydrogen. In this work, Fe–Ni–B/Cu(OH)2–Cu foam was synthesized by combining in situ growth and electroless plating. Compared with the binary Fe–B/Cu(OH)2–Cu foam and Ni–B/Cu(OH)2–Cu foam prepared by the same method, the ternary Fe–Ni–B/Cu(OH)2–Cu foam has superior catalytic performance. The Fe–Ni–B/Cu(OH)2–Cu foam catalyst was able to achieve a maximum hydrogen production rate of 5.6 ml min−1 cm−2 at 298 K with an activation energy as low as 46.3 kJ mol−1. And more importantly, its catalytic efficiency has hardly decayed after ten cycles. These excellent properties are due to its low activation energy and the large specific surface, multi–site Cu(OH)2–Cu–foam carrier.

A robust sandwich structural catalyst of (Cu/CuCo-MOF)2/MXene double heterojunction with outstanding activity toward hydrogen generation

Non-noble metal catalysts have exhibited promising prospects in ammonia borane (NH3BH3) hydrolysis, but their activity and stability still need to be further improved. Herein, a 2D sandwich heterostructural catalyst with Cu/CuCo-MOF and MXene-MOF double heterojunction has been prepared by coupling Ti3C2Tx MXene with bimetal organic framework nanosheets using a facile in situ growth strategy. The optimized CuCo-MOF/MX exhibits unprecedented activity with a turnover frequency (TOF) of 82.3 min–1 and excellent cycle stability, comparable to precious metal catalysts. Spectroscopic characterization and density functional theory (DFT) calculations reveal that Cu/CuCo-MOF heterojunction provides CuCo dual active sites for catalysis, and MXene-MOF heterojunction modulates the electronic structure and valence states of Cu sites via the Ti3C2Tx interlayer with 2D electron promoter effect to improve the synergistic effect of CuCo dual active sites. These modulation optimize the adsorption and dissociation of reactants, leading to a lower reaction barrier. This work provides insight into the 2D electron promoter effect, proposes a novel strategy for improving the performance of non-precious metal catalysts through constructing double heterojunction with 2D electron promoter effect.

Hydrogen generation from catalytic hydrolysis of ammonia borane with Co-Cu-B/g-C3N4/NF catalyst

In this study, different double-supported Co-Cu-B/g-C3N4/Ni foam (NF=Ni foam) catalysts were synthesized by chemical deposition method in a certain pH value range (pH value between 10.5 and 12.0). Their catalytic performances of hydrolyzing ammonia borane (NH3BH3) hydrolysis were investigated to produce hydrogen at 298 K. Because of the adding of g-C3N4 in the plating solution, the obtained sample had certain photocatalytic activity when the visible light was introduced the hydrolysis experiment. The results displayed that the as-prepared Co-Cu-B/g-C3N4/NF catalyst at pH = 10.5 exhibited an improved catalytic effect for NH3BH3 hydrolysis under visible light irradiation. The corresponding hydrogen generation rate reached 8893 mol·min−1·g−1, and the activation energy was 41.8 kJ·mol−1. The catalytic performance of Co-Cu-B/g-C3N4/NF catalysts prepared by this method is better than that of as-obtained mono-metal Co-B/g-C3N4/NF catalyst. More importantly, its activity has exceeded many single-carrier cobalt-based catalysts reported so far, and even some single-support precious metal catalysts for NH3BH3 hydrolysis. It indicated that the strategy of double carriers and introduction of light contributed to the improvement in catalytic activity for the non-noble metal-based catalysts during NH3BH3 hydrolysis.

Metal-organic framework-derived carbon-supported high-entropy alloy nanoparticles applied in ammonia borane hydrolytic dehydrogenation

While high-entropy alloy nanoparticle (HEA NP) catalysts from a sacrificial high-entropy-MOF (HE-MOF) have been attractive, their conventional characterizations may be misleading. Here, we report HEA NPs on HE-MOF-derived carbon (HE-MDC) via direct pyrolysis of MnFeCoNiCu HE-MOF in Ar and H2 at different temperatures and durations with a fast-ramping rate. With the profound investigations of the metal NPs on HE-MDCs by synchrotron radiation X-ray diffraction and absorption, we revealed that the Ar-treated HE-MDCs had either Cu-dominant solid solution or phase-segregated metal NPs, whereas H2 pyrolysis yielded well-dispersed HEA NPs on HE-MDCs. For ammonia borane hydrolysis, although the metal NP size in H2-treated HE-MDC was not the smallest, it showed the fastest dehydrogenation rate (TOF=5.76 molH₂∙min−1∙molcat-1), 2 ∼ 4 times faster than the Ar-treated HE-MDCs. It emphasized the crucial role of elemental uniformity in the HEA NPs over the traditionally reported catalyst size.