Hydrolysis Of Sodium Borohydride Research Articles

One-pot synthesis of magnetic copper ferrite nanocubes for hydrogen production by hydrolysis of sodium borohydride

This work describes the hydrogen production from sodium borohydride (NaBH4) hydrolysis over the homogenous copper ferrite (CuFe2O4) nanocubes which were produced by one-pot approach without using any surfactant. The CuFe2O4 nanocubes have a dimension of about 100 nm in size. X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphology, structure, and phase of the sample. The magnetic CuFe2O4 nanocubes were utilized in the hydrolysis of NaBH4 to produce hydrogen, and demonstrated good catalytic activity and recyclability. The rate of hydrogen production of 10 wt% NaBH4 hydrolysis reached up to 1.5 L/min/g at 303 K over CuFe2O4 nanocubes, which is substantially greater than in other shaped CuFe2O4 materials. In the hydrogen generation process, the effects of NaOH concentration, NaBH4 concentration, and reaction temperature were also investigated. Magnetic CuFe2O4 nanocubes show a comparatively low activation energy of 41.53 kJ/mol, according to the kinetic analyses. Hence, the uniform CuFe2O4 nanocubes have much potential in hydrolysis for hydrogen generation.

Synthesis of cobalt-doped catalyst for NaBH4 hydrolysis using eggshell biowaste

In the present study, a cobalt-doped catalyst was prepared from chicken eggshell powder (CEP) biowaste to be used in the hydrolysis of sodium borohydride (NaBH4). In the presence of the prepared catalyst (CEPcat), possible effects of the parameters of NaOH concentration (%), catalyst amount (g), NaBH4 concentration (%), process temperature (oC) and reusability affecting the hydrolysis of sodium borohydride were examined. The CEPcat obtained was characterized with FT-IR, TGA, XRD, SEM and EDX analyses. The hydrogen generation rate (HGR) was determined as 432 mL gCo−1 min−1 in the presence of 1 g CEPcat, a CoO/CaO ratio of 10/90 and 1% NaBH4 concentration. The activation energy of the NaBH4 hydrolysis reaction was calculated as 16.78 kJ mol−1. After 16 reuses of the CEPcat there was no significant decrease in the hydrogen volume. Compared to the first use while there was an increase in the HGR. These results showed that the CEPcat prepared has a significant advantage over other catalysts for use in NaBH4 hydrolysis.

Effect of environmentally friendly and efficient metal-free hydrochars as catalysts on sodium borohydride hydrolysis

Environmentally friendly, metal-free catalysts are important to synthesize and use, as are catalysts made from biomass-based. This study aims to obtain hydrochars from pine cones and rheum ribes shells by the hydrothermal method and use this hydrochar as a catalyst in sodium borohydride hydrolysis.The characterization of the synthesized catalyst hydrochars was carried out by XRD, BET, SEM, EDX, ICP-OES and FTIR analyses. X-ray diffraction analysis of pinecone hydrochar and rheum ribes shells hydrochar has revealed that they are both amorphous and crystalline in structure. The BET surface areas of the two hydrochars are 1.6 m2/g and 19.01 m2/g, respectively. The activity of hydrochars on the hydrolysis of sodium borohydride was evaluated under microwave irradiation at different temperatures, catalyst amounts, and different microwave powers. The hydrolysis kinetics of NaBH4 in the presence of pine cone and rheum ribes shells hydrochars catalysts were determined according to the nth-order and the Langmuir-Hinshelwood kinetic models. The activation energies for the rheum ribes shells and pine cone hydrochars catalysts were calculated to be 88.29 kJ/mol and 78 kJ/mol, respectively. It was concluded that hydrochar prepared from waste material extract through the eco-friendly green synthesis method is promising for the hydrolysis of NaBH4.

Fabrication and characterization of poly(tannic acid) coated magnetic clay decorated with cobalt nanoparticles for NaBH4 hydrolysis: RSM-CCD based modeling and optimization

Hydrogen generation from sodium borohydride (NaBH4) hydrolysis in the presence of metal catalysts is a frequently used and encouraging method for hydrogen storage. Metal nanoparticle-supported catalysts are better recyclability and dispersion than unsupported metal catalysts. In this study, the synthesis and characterization of a polymer-supported catalyst for hydrogen generation using NaBH4 have been investigated. For the synthesis of polymeric material, first of all, kaolin (KLN) clay has been magnetically rendered by using the co-precipitation method (Fe3O4@KLN) and then coated with poly tannic acid (PTA@Fe3O4@KLN). Then, the catalyst loaded with cobalt (Co) nanoparticles have been obtained with the NaBH4 reduction method (Co@PTA@Fe3O4@KLN). The surface morphology and structural properties of the prepared catalysts have been determined using methods such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS) and vibrating sample magnetometer (VSM). The optimization of the most important variables (NaBH4 amount, NaOH amount, catalyst amount, and metal loading rate) affecting the hydrolysis of NaBH4 using the synthesized polymeric catalysts was carried out using response surface methodology (RSM). Depending on the evaluated parameters, the desired response was determined to be hydrogen production rate (HGR, mL/g min). HGR was 1540.4 mL/gcat. min. in the presence of the Co@PTA@Fe3O4@KLN at optimum points obtained via RSM (NaBH4 amount 0.34 M, NaOH amount 7.9 wt%, catalyst amount 3.84 mg/mL, and Co loading rate 6.1%). The reusability performance of the catalyst used in hydrolysis of NaBH4 was investigated under optimum conditions. It was concluded that the catalyst is quite stable.

Poly(2-aminoethyl methacrylate) based microgels catalyst system to be used in hydrolysis and methanolysis of NaBH4 for H2 generation

The poly(2-aminoethyl methacrylate) (p(AEM)) microgels were synthesized by microemulsion polymerization technique and used for in situ metal nanoparticle preparation to render as p(AEM)-M (M: Co or Ni) microgel composites and were used in p(AEM) based poly ionic liquid (PIL) microgels. Next, these p(AEM)) based microgel materials were used as catalysts for hydrogen (H2) production from both hydrolysis and methanolysis reactions of sodium borohydride (NaBH4). It was found that the catalytic hydrolysis of the NaBH4 reaction, catalyzed by p(AEM)-Co microgel composite was completed in 140 min, whereas the methanolysis of NaBH4 methanolysis catalyzed by the PIL of p(AEM)+Cl− microgels was completed in 5 min both with 250 ± 2 mL H2 production. Furthermore, p(AEM)-Co microgel composite catalysts maintained 80% catalytic activity after 5 consecutive uses in NaBH4 hydrolysis. On the other hand, p(AEM)+Cl− microgels were found to afford more than 50% catalytic activity even after 20 repetitive use in NaBH4 methanolysis due to superior regeneration ability. Moreover, activation energy values for p(AEM)-Co microgel composites catalyzed NaBH4 hydrolysis reaction were calculated as 38.9 kJ/mol in comparison to 37.3 kJ/mol activation energy of p(AEM)+Cl− microgel catalyzed methanolysis reaction.

Hydrogen generation system for fuel cells based on high pressure hydrolysis of solid-state sodium borohydride

The aim of this study was to produce sufficient hydrogen for high-power fuel cell applications through acid-accelerated hydrolysis of sodium borohydride (SBH) with liquid water. Liquid hydrolysis of SBH was performed under high temperatures (160–200 ℃) and high pressure (40 bar) conditions. The characteristics of the liquid hydrolysis of SBH were analyzed according to the feed injection rate, reactant temperature, and excess stoichiometric number. In addition, 11B solid NMR spectroscopy was conducted to analyze the composition of the reaction product. In all experimental cases, the conversion of SBH was ≥95%, and a maximum of 6.71 wt% gravimetric hydrogen density was achieved. The experimental results indicated that it is possible to control the rate of hydrogen generation through the feed injection rate. This suggests that hydrogen can be supplied to varying-output fuel cell applications using this system. In addition, as a result of experiments according to the reactant temperature, it was demonstrated that the lower the reactant temperature, the less hydrogen produced, and the greater the unreacted residual SBH. Moreover, when the excess stoichiometric ratio increased, the gravimetric hydrogen density decreased. This reduced the viscosity of the reaction product and the amount of unreacted SBH observed when the reaction was conducted at low reactant temperatures. Therefore, it is possible to consider increasing the excess stoichiometric number for practical purposes.

Electrospun NiPd Nanoparticles Supported on Polymer Membrane Nanofibers as an Efficient Catalyst for NaBH4 Dehydrogenation.

Sodium borohydride (SBH) hydrolysis in the presence of cheap and efficient catalysts has been proposed as a safe and efficient method for generating clean hydrogen energy for use in portable applications. In this work, we synthesized bimetallic NiPd nanoparticles (NPs) supported on poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers (PVDF-HFP NFs) via the electrospinning approach and reported an in-situ reduction procedure of the NPs being prepared by alloying Ni and Pd with varying Pd percentages. The physicochemical characterization provided evidence for the development of a NiPd@PVDF-HFP NFs membrane. The bimetallic hybrid NF membranes exhibited higher H2 production as compared to Ni@PVDF-HFP and Pd@PVDF-HFP counterparts. This may be due to the synergistic effect of binary components. The bimetallic Ni1-xPdx(x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3)@PVDF-HFP nanofiber membranes exhibit composition-dependent catalysis, in which Ni75Pd25@PVDF-HFP NF membranes demonstrate the best catalytic activity. The full H2 generation volumes (118 mL) were obtained at a temperature of 298 K and times 16, 22, 34 and 42 min for 250, 200, 150, and 100 mg dosages of Ni75Pd25@PVDF-HFP, respectively, in the presence of 1 mmol SBH. Hydrolysis utilizing Ni75Pd25@PVDF-HFP was shown to be first order with respect to Ni75Pd25@PVDF-HFP amount and zero order with respect to the [NaBH4] in a kinetics study. The reaction time of H2 production was reduced as the reaction temperature increased, with 118 mL of H2 being produced in 14, 20, 32 and 42 min at 328, 318, 308 and 298 K, respectively. The values of the three thermodynamic parameters, activation energy, enthalpy, and entropy, were determined toward being 31.43 kJ mol-1, 28.82 kJ mol-1, and 0.057 kJ mol-1 K-1, respectively. It is simple to separate and reuse the synthesized membrane, which facilitates their implementation in H2 energy systems.

Membrane Nanofiber-Supported Cobalt–Nickel Nanoparticles as an Effective and Durable Catalyst for H2 Evolution via Sodium Borohydride Hydrolysis

The successful support of bimetallic NiCo alloy nanoparticles (NPs) on poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers (PVDF-HFP NFs) was achieved through electrospinning (ES) and in situ reduction. The synthesis and physicochemical characterization of Ni-Co@PVDF-HFP NFs with a range of bimetallic compositions (Ni1-xCox, x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1) supported on PVDF-HFP NFs was undertaken. In comparison to their counterparts (Ni-PVDF-HFB and Co-PVDF-HFB), the bimetallic hybrid NF membranes demonstrated a significantly increased volume of H2 generation from sodium borohydride (SBH). The high performance of bimetallic catalysts can be attributed mostly to the synergistic impact of Ni and Co. Among all fabricated catalysts, Ni0.3Co0.7@PVDF-HFP produced the highest H2 production in a short time. The maximum generated H2volume was 118 mL in 11.5, 9, 6, and 4.5 min at 298, 308, 318, and 328 K, respectively. Kinetic analyses showed that the hydrolysis process proceeded as a quasi-first-order reaction with respect to the amount of catalyst and as a zero-order reaction with respect to the concentration of SBH. Thermodynamics studies were also undertaken and the parameters were calculated as Ea, ΔS, and ΔH = 30.17 kJ/mol, 0.065 kJ/mol, and 27.57 kJ/mol K, respectively. The introduced NFs can be easily separated and reused, which facilitates their industrialization and commercialization applications in hydrogen storage systems.

Coronavirus-like Core-Shell-Structured Co@C for Hydrogen Evolution via Hydrolysis of Sodium Borohydride.

Constructing a reliable and robust cobalt-based catalyst for hydrogen evolution via hydrolysis of sodium borohydride is appealing but challenging due to the deactivation caused by the metal leaching and re-oxidization of metallic cobalt. A unique core-shell-structured coronavirus-like Co@C microsphere was prepared via pyrolysis of Co-MOF. This special Co@C had a microporous carbon coating to retain the reduced state of cobalt and resist the metal leaching. Furthermore, several nano-bumps grown discretely on the surface afforded enriched active centers. Applied in the pyrolysis of NaBH4, the Co@C-650, carbonized at 650 °C, exhibited the best activity and reliable recyclability. This comparable performance is ascribed to the increased metallic active sites and robust stability.

Palladium based bimetallic nanocatalysts: Synthesis, characterization and hydrogen fuel production

In this study, Palladium dopped Copper oxide nanoparticles (CuO@Pd NPs) were synthesized by an environmentally friendly green synthesis method for hydrogen production experiments. Characterizations of synthesized nanoparticles; UV–vis Spectroscopy to characterize the optical properties, Scanning Electron Microscopy (SEM) to determine the morphology and particle size of the particles, Fourier Transform Infrared Spectroscopy (FTIR) for the analysis of organic groups, and X-ray Diffraction Spectroscopy (XRD) for the crystal lattice type analysis were used. As a result of the UV–vis Spectroscopy characterization of the synthesized nanoparticles, an absorption peak compatible with metals visible at 422 nm was observed. According to the XRD analysis results, the crystal size observed in the cubic phase was calculated as approximately 4.426 nm. According to the results of the SEM analysis the average particle size of the cubic nanoparticles was seen as 26.2 nm. The catalytic properties of CuO@Pd NPs were determined by the sodium borohydride hydrolysis reaction. As a result of catalyst, substrate, temperature, and reusability experiments, some activation parameters required for a catalytic reaction of nanoparticles were calculated. The activation energy of CuO@Pd NPs was calculated as 37.39 kJ/mol, enthalpy change as 34.84 kJ/mol, and entropy change as −189.8 J/mol.K. TOF, which is an indicator of hydrogen efficiency, was calculated as 1513.4 h−1. Reusability experiments were carried out in 4 cycles and the catalytic activity of CuO@Pd NPs was measured as 70 %. In light of these results, it was seen that nanoparticles provide optimal conditions for a catalytic reaction.

Acid-accelerated hydrolysis of NaBH4: a gas-generation reaction for diverse gas pressure biosensing.

Gas pressure biosensing is a promising portable analysis method. The gas-generation reaction is crucial to its sensitivity, speed, repeatability, and usability. However, very few gas-generation reactions are available for sensitive, safe, and diverse biosensing. Herein, acid-accelerated hydrolysis of sodium borohydride (NaBH4) was explored for the first time to achieve portable and diverse gas pressure biosensing. The slow hydrolysis and hydrogen generationof NaBH4 inalkaline medium isaccelerated with increasing acidity, which increased the gas pressure in a small and sealed tube within 10min. Thus, alabel-free bioassay is easily and specifically achieved once analytes can in-situ generate acid to accelerate the hydrolysis rate of NaBH4, such as glucose, acetylcholine (ACh), adenosine triphosphate (ATP) and others. More importantly, analytes without acid generation could be quantitatively and selectively detected by combining target recognition with acid-generated biochemical reactions for enzyme-linked gas pressure biosensing. Inspired by this, aflatoxin B1 (AFB1)-aptamer interaction-triggered strand displacement reaction was combined with glucose oxidation by glucose oxidase (GOD) to detect AFB1 as low as 7.1pM. Therefore, acid-accelerated hydrolysis of NaBH4 is powerful for developing portable, cheap, and diverse gas pressure biosensing. It opens up a new way for cheap, universal, and portable biosensing.

Electrospun Co Nanoparticles@PVDF-HFP Nanofibers as Efficient Catalyst for Dehydrogenation of Sodium Borohydride.

Metallic Co NPs@poly(vinylidene fluoride-co- hexafluoropropylene) nanofibers (PVFH NFs) were successfully synthesized with the help of electrospinning and in situ reduction of Co2+ ions onto the surface of PVFH membrane. Synthesis of PVFH NFs containing 10, 20, 30, and 40 wt% of cobalt acetate tetrahydrate was achieved. Physiochemical techniques were used to confirm the formation of metallic Co@PVFH NFs. High catalytic activity of Co@PVFH NFs in the dehydrogenation sodium borohydride (SBH) was demonstrated. The formulation with 40 wt% Co proved to have the greatest performance in comparison to the others. Using 1 mmol of SBH and 100 mg of Co@PVFH NFs, 110 mL of H2 was produced in 19 min at a temperature of 25 °C, but only 56, 73, and 89 mL were produced using 10, 20, and 30 wt% Co, respectively. With the rise of catalyst concentration and reaction temperature, the amount of hydrogen generated increased. By raising the temperature from 25 to 55 °C, the activation energy was lowered to be 35.21 kJ mol-1 and the yield of H2 generation was raised to 100% in only 6 min. The kinetic study demonstrated that the reaction was pseudo-first order in terms of the amount of catalyst utilized and pseudo-zero order in terms of the SBH concentration. In addition, after six cycles of hydrolysis, the catalyst showed outstanding stability. The suggested catalyst has potential applications in H2 generation through hydrolysis of sodium borohydride due to its high catalytic activity and flexibility of recycling.

CuNi Alloy NPs Anchored on Electrospun PVDF-HFP NFs Catalyst for H2 Production from Sodium Borohydride.

Non-noble CuxNi1-x (x = 0, 0.1, 0,2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1) alloy nanoparticles supported on poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) nanofibers (NFs) are successfully fabricated. The fabrication process is executed through an electrospinning technique and in situ reduction in Cu2+ and Ni2+ salts. The as-synthesized catalysts are characterized using standard physiochemical techniques. They demonstrate the formation of bimetallic NiCu alloy supported on PVDF-HFP. The introduced bimetals show better catalytic activity for sodium borohydride (SBH) hydrolysis to produce H2, as compared to monometallic counterparts. The Cu0.7 Ni0.3/PVDF-HFP catalyst possesses the best catalytic performance in SBH hydrolysis as compared to the others bimetallic formulations. The kinetics studies indicate that the reaction is zero order and first order with respect to SBH concentration and catalyst amount, respectively. Furthermore, low activation energy (Ea = 27.81 kJ/mol) for the hydrolysis process of SBH solution is obtained. The excellent catalytic activity is regarded as the synergistic effects between Ni and Cu resulting from geometric effects over electronic effects and uniform distribution of bimetallic NPs. Furthermore, the catalyst displays a satisfying stability for five cycles for SBH hydrolysis. The activity has retained 93% from the initial activity. The introduced catalyst has broad prospects for commercial applications because of easy fabrication and lability.

Catalytic hydrolysis of sodium borohydride for hydrogen generation using g-C3N4/Co–W–B/Ni foam composite catalyst

Catalytic hydrolysis of sodium borohydride for hydrogen generation using g-C3N4/Co–W–B/Ni foam composite catalyst

Green preparation of silver nanocluster composite AgNCs@CF-g-PAA and its application: 4-NP catalytic reduction and hydrogen production.

4-Nitrophenol (4-NP) is a serious organic environmental pollutant. Conversion of 4-nitrophenol to 4-aminophenol (4-AP) by catalytic hydrogenation is an effective solution. In this work, a catalyst (AgNCs@CF-g-PAA) loaded with silver nanoclusters (AgNCs) was prepared by radiation technique. Firstly, the template polyacrylic acid (PAA) was grafted onto the cotton fiber (CF) by radiation grafting technique to obtain a solid template (CF-g-PAA). After that, AgNCs were synthesized in situ on CF-g-PAA by radiation reduction, and the composite material AgNCs@CF-g-PAA was obtained directly. AgNCs@CF-g-PAA has an obvious photoluminescence phenomenon, which is attributed to the stable AgNCs binding to the carboxyl on the PAA molecular chain. Due to the extremely small size of AgNCs, AgNCs@CF-g-PAA has good catalytic characteristics. The prepared AgNCs@CF-g-PAA catalyst has a very high catalytic rate for the hydrogenation of 4-NP. Even at high concentrations of 4-NP, AgNCs@CF-g-PAA can still maintain a high catalytic rate. At the same time, the AgNCs@CF-g-PAA catalyst can also be used to catalyze the rapid hydrolysis of sodium borohydride, which is conducive to hydrogen production. In summary, we have prepared a practical catalyst AgNCs@CF-g-PAA with high catalytic performance based on cheap raw materials and a simple synthesis route, which provides a catalyst candidate for the treatment of water contaminant 4-NP and the production of hydrogen from sodium borohydride.

Sodium borohydride hydrolysis over mesoporous spherical carbon obtained from jasmine flower extract

In this contribution, we have utilized Jasmine flower (Tabernaemontana divaricata) extract as a green source during the synthesis of carbon under hydrothermal conditions. Phase characterization indicated that the prepared material is graphitic carbon with various functional groups. TEM images revealed that the prepared material is composed of quasi-spherical particles having diameters in the 15 nm range, which are accumulated in micro-spherical ones as indicated by SEM images. N2-adsorption measurements indicated that this spherical carbon possesses a mesoporous character. XPS data revealed the co-existence of various C, N, and O species at the surface of this carbon. Sodium borohydride (NaBH4) hydrolysis activity of the synthesized carbon was investigated over the 25–45 °C range of temperature. The catalytic activity was found to increase with both the temperature and NaBH4 concentration (up to 5 wt. %). Moreover, the activity was quenched in the presence of strong bases.

Examination of the catalytic effect of Ni, NiCr, and NiV catalysts prepared as thin films by magnetron sputtering process in the hydrolysis of sodium borohydride

In this study, nickel, nickel-chromium alloy, and nickel-vanadium alloy were coated to form a thin film on the slides prepared by magnetron sputtering process, which were used as a catalyst for the hydrolysis of alkaline sodium borohydride. Factors, such as the temperature of the solution, amount of the catalyst, initial pH of the solution and the performance of these catalysts on hydrogen generation rate were investigated using response surface methodology. Moreover, the catalysts were characterized using XRD and FE-SEM/EDS analyses. Utilizing the obtained optimum conditions of the response surface methodology estimation, the maximum hydrogen generation rate was 35,071 mL min−1 gNiV−1 from NiV catalyst at 60 °C, pH 6, and 1.75 g catalyst conditions. Under the same experiment conditions, the maximum hydrogen generation rates of Ni and NiCr catalyst systems are 28,362 mL min−1 gNi−1, and 30,608 mL min−1 gNiCr−1, respectively.

Cobalt-nickel bimetal carbon sphere catalysts for efficient hydrolysis of sodium borohydride: The role of synergy and confine effect

Sodium borohydride exhibits great potential in the field of chemical hydrogen storage. A competent catalyst would accelerate its practical application for hydrogen utilization by enhance the efficiency of hydrogen generation from hydrolysis of sodium borohydride. Herein, a kind of highly efficient and durable synergistic Co–Ni bimetal inlaid carbon sphere catalyst (Co-NiΦC) was prepared by a co-pyrolysis method, of which the configuration of metal inlaid carbon sphere could effectively expose and anchor the active component by contrast with the capsule catalyst (Co–Ni@C) and supported catalyst (Co–Ni/C). Further, diverse cobalt-nickel contents of the Co-NiΦC catalysts were optimized to achieve the best hydrolysis performance of sodium borohydride. The structure-performance relationship of inlaid catalyst and the bimetallic synergistic mechanism were investigated by multiple characterization measurements and the density functional theory (DFT). As demonstrated, the inlaid Co-NiΦC-2 catalyst (Co/Ni molar ratio of 8/2) shows a promising catalytic activity of hydrogen generation rate up to 6364 mLH2·min−1·gmetal−1, a relative low reaction activation energy of 30.3 kJ/mol as well as robust durability where it still remains about 83.4% of its initial reaction rate after the fifth cycle. The outstanding performance of the optimized catalyst may ascribe to the high dispersion, remarkable Co–Ni synergy and high stabilization of the Co–Ni nanoparticles under the confinement effect of the inlaid metal-carbon sphere configuration. This work provides an alternative avenue for the application of efficient carbon-supported bimetal catalysts in the future.

Effect of Titanium Dioxide Support for Cobalt Nanoparticle Catalysts for Hydrogen Generation from Sodium Borohydride Hydrolysis

Effect of Titanium Dioxide Support for Cobalt Nanoparticle Catalysts for Hydrogen Generation from Sodium Borohydride Hydrolysis

Ultrasmall bimetallic Ru-Co alloy nanoclusters immobilized in amino-functionalized UiO-66 and N-doped carbonaceous zirconium oxide nanocomposite for hydrogen generation

To satisfy global energy demands and maintain sustainable levels of atmospheric greenhouse gases, alternative energy sources are required. H 2 generation from hydrolysis of NaBH 4 represents as a safe and convenient method for storing and releasing H 2 . The free amine groups (NH 2 ) and the big pores in the NH 2 -UiO-66 metal-organic framework were exploited to encapsulate ultrasmall bimetallic Ru-Co alloy nanoclusters and monometallic Ru and Co nanoclusters with an average particle size of 1.5 nm via direct anionic exchange technique. To prove the role of the NH 2 groups and the MOF’s pores in the creation of a well and uniform-dispersed ruthenium and cobalt nanoclusters, the NH 2 -UiO-66 was calcined at 600 °C for 3 h in the air to prepare N-doped carbonaceous ZrO 2 (ZrO 2 N @ C) nanocomposite. Hydrazine hydrate (HH) was used as a reducing agent in the presence of microwave irradiation (MWI). The prepared catalysts were used as novel catalysts for hydrogen generation, via the hydrolysis of sodium borohydride (NaBH 4 ). 2 wt% Ru-Co/NH 2 -UiO-66 displays a high hydrogen generation rate (HGR) of 10526 mL H 2 g −1 min −1 from low concentration NaBH 4 solution (50 mM). The extraordinary catalytic activity of the prepared catalysts attributes to the ultrasmall particle size of the ruthenium and cobalt nanoclusters in the MOF’s pores, the synergistic harmony between the Ru and Co nanoclusters in the alloy form, and the large surface area of the NH 2 -UiO-66. The effect of the NaBH 4 concentration, catalyst amount, and reaction temperatures (30–60 °C) was investigated. The catalyst shows high recyclability efficiency for at least five cycles, due to the high leaching resistance of the alloy nanoclusters within the MOF host. The prepared catalysts may be considered as highly efficient catalysts for energy-based applications. • Preparation of ultrasmall single alloy Ru-Co nanoclusters without ligand. • The free amine groups in the NH 2 -UiO-66 provide coordination sites for metal ions. • Synthesis of N-doped carbonaceous ZrO 2 (ZrO 2 N @ C) derived from NH 2 -UiO-66. • Reduction of Ru and Co ions with hydrazine hydrate under MWI. • Ru-Co/NH 2 -UiO-66 achieves a high hydrogen generation rate of 10526 mL g cat −1 min −1 .