Catalyst For NaBH4 Hydrolysis Research Articles

Synthesis of Trimetallic Nanoparticle (NiCoPd)-Supported Carbon Nanofibers as a Catalyst for NaBH4 Hydrolysis.

The generation of H2 via the catalytic hydrolysis of sodium borohydride (SBH) has promise as a practical and secure approach to produce H2, a secure and environmentally friendly energy source for the foreseeable future. In this study, distinctive trimetallic NiCoPd nanoparticle-supported carbon nanofibers (NiCoPd tri-NPs@CNFs) is synthesized via sol-gel and electrospinning approaches. The fabricated trimetallic catalysts show an excellent catalytic performance for the generation of H2 from the hydrolysis of SBH. Standard physicochemical techniques were used to characterize the as-prepared NiCoPd tri-NPs@CNFs. The results show that NiCoPd tri-NPs@CNFs is formed, with an average particle size of about 21 nm. When compared to NiCo bimetallic NP @CNFS, all NiCoPd tri-NPs@CNFs formulations demonstrated greater catalytic activates for the hydrolysis of SBH. The improved catalytic activity may be due in the majority to the synergistic interaction between the three metals in the trimetallic architecture. Furthermore, the activation energy for the catalytic hydrolysis of SBH by the NiCoPd tri-NPs@CNFs was determined to be 16.30 kJ mol-1. The kinetics studies show that the reaction is of a first order with respect to the catalyst loading amount and a half order with respect to the SBH concentration [SBH].

Facile “Green” synthesis of a novel Co–W–B catalyst from Rheum ribes shell extract and its effect on sodium borohydride hydrolysis: Kinetic mechanism

The present investigation aimed to assess the influence of the Co–W–B NPs catalyst on the process of sodium borohydride hydrolysis. The study involved the synthesis of Co–W–B NPs through the utilization of an eco-friendly green synthesis extract derived from the Rheum ribes shell in conjunction with the chemical reduction technique for catalyst production. The investigation of catalysts' structure and surface morphology was conducted through the utilization of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR) techniques. The average particle size was determined to be 35 nm in TEM analysis. The presence of Co–W–B nanoparticles and their elemental composition % were determined through EDX analysis, revealing values of 63.9% (Co), 31.89% (C), 1.75% (B), and 2.46% (W) within the nanoparticle. The manufactured Co–W–B catalyst's use for hydrolysis of sodium borohydride was studied under various conditions, including different concentrations of NaOH and NaBH4, different amounts of catalyst, and different temperature parameters. The hydrogen production rate for the Co–W–B NPs catalyst in NaBH4 hydrolysis was determined to be 5367 mLg−1min−1 at 30 °C. The study involved the determination of TOF values for a catalyst composed of Co–W–B NPs, which were subjected to varying temperatures. The activation energies were determined through the utilization of the n-th order and Langmuir-Hinshelwood kinetic models and subsequently calculated using the Arrhenius equation, resulting in values of 35.36 and 31.70 kJ/mol, respectively. The values of enthalpy and entropy, ΔH and ΔS, were determined through the utilization of Eyring's equation, 18.49 kJ/mol and −80.7 J/mol.K, respectively.

Development of highly efficient and reusable Ruthenium complex catalyst for hydrogen evolution

Herein, we report an efficient, environmentally friendly and stable catalyst development to hydrogen evolution from sodium borohydride hydrolysis. For this purpose, Ruthenium complex catalyst successfully fabricated via 5-Amino-2,4-dichlorophenol-3,5-ditertbutylsalisylaldimine ligand and RuCl3·H2O salt. Ru complex catalyst was identified with X-Ray Diffraction Analysis, Infrared Spectroscopy, Elemental Analysis, Transmission electron microscopy, Scanning Electron Microscope and Brunauer-Emmett-Teller Surface Area Analysis. According to the analysis results, it was confirmed that Ru complex catalyst was successfully synthesized. Ru complex was used as a catalyst in NaBH4 hydrolysis. The kinetic performance of Ru complex catalyst was evaluated at various reaction temperatures, various sodium borohydride concentration, catalyst concentration and sodium hydroxide concentration in hydrogen evolution. The apparent activation energy for the hydrolysis of sodium borohydride was determined as 25.8 kJ mol−1. With fully conversion, the promised well durability of Ru complex was achieved by the five consecutive cycles for hydrogen evolution in sodium borohydride hydrolysis The hydrogen evolution rates were 299,220 and 160,832 mL H2 gcat−1 min−1 in order of at 50 °C and 30 °C. Furthermore, the proposed mechanism of Ru complex catalyzed sodium borohydride hydrolysis was defined step by step. This study provides different insight into the rational design and utilization and catalytic effects of ruthenium complex in hydrogen evolution performance.

The activity of ceria supported complex in hydrogen generation

In this study, we studied the ceria supported Ni complex preparation and using it as a catalyst in NaBH4 hydrolysis for H2 production. NaBH4 hydrolysis system was studied in different parameters, as concentration of Ni complex, concentration of NaBH4, concentration of NaOH, amount of catalyst and temperature. Additionally, catalyst was characterized by several analysis methods. Finally, the kinetic calculation of NaBH4 hydrolysis reaction was studied at 20 ℃-50 ℃ the activation energy was found to be 27.581 kJ/mol. The aim of this study is to emphasize that ceria support can be used to increase the catalyst surface and to obtain the high hydrogen generation activity through hydrolysis of NaBH4. The experimental results show that ceria supported Ni complex was an effective catalyst in hydrolysis of NaBH4.

Layered double hydroxide supported cobalt nanocluster: size control and the effect in catalytic hydrogen generation

Synthesizing metal nanoclusters with diameters smaller than 5nm is challenging, but desirable because of the high ratio of surface area to interior atom. However, in this report it was achieved by utilizing magnesium-aluminium layered double hydroxide (Mg/Al-LDH) as a host for cobalt citrate anion precursor, which was later reduced into cobalt nanoclusters (Co-NC). Size of the Co-NC was controlled by changing the concentration of cobalt-citrate (Co-citrate) precursor during anion exchange. XRD and FTIR showed that Co-citrate precursor was successfully intercalated on the LDH while nitrogen adsorption/desorption isotherms confirmed that mesopores in the sample were formed after chemical reduction. Furthermore, TEM/STEM observations confirmed the formation of Co-NC. It was also verified that reducing the concentration of Co-citrate from 4mM to 0.5mM resulted in a reduction in the size of Co-NC from 4.4 to 1.3 nm. However, catalytic hydrogen generation from sodium borohydride (NaBH4) hydrolysis experiment indicated that catalytic activity decreased as the size of Co-NC decreases. This is mainly attributed to the limitation in mass transport within the interlamellar space of the smaller cluster LDH compared to the bigger one. Overall, Co-NC-LDH is a promising catalyst for NaBH4 hydrolysis. However, an optimum Co-NC size is critical for enhanced catalytic activity.

Cobalt oxide supported multi wall carbon nanotube catalysts for hydrogen production via sodium borohydride hydrolysis

Cobalt oxide supported multi-wall carbon nanotubes (Co/MWCNTs) catalysts with different cobalt oxide loadings were synthesized by simple impregnation method. The synthesized Co/MWCNTs materials were used as catalysts for hydrolysis of sodium borohydride (NaBH4), an effective route to produce clean hydrogen. The effect of some parameters such as Co loading, reaction temperature and reaction time were investigated on the performance of catalysts in hydrolysis of NaBH4. The hydrogen generation rate was found to be 409 mLg−1min−1 at 35 °C for Co/MWCNTs-20 catalyst in NaBH4 hydrolysis, while it is 28 mLg−1min−1 for bulk MWCNTs support. The physico-chemical characteristics such as crystalline phase, morphology, particle size, reducibility, surface and textural properties of the catalysts were studied by using powder XRD, FE-SEM, TEM, N2-physorption, XPS and H2-TPR techniques. The reduction temperature of cobalt oxide species was shifted to lower temperatures after impregnation of nanosized Co oxides on the MWCNTs support. It was also observed that presence of more number of surface Co2+ species in Co/MWCNTs-20 catalyst is responsible for superior activity in catalytic hydrolysis of NaBH4. The obtained results also suggested that Co/MWCNTs catalysts can be reused for five cycles with a slight loss of activity.

Hydrogen Generation by Hydrolysis of NaBH4 with Efficient Co–La–Mo–B Catalyst for PEM Fuel Cells

In this study, Co–La–Mo–B catalyst used for hydrogen production by hydrolysis of sodium borohydride (NaBH4) solution was synthesized by chemical reduction method. Characterization of the synthesized catalyst was carried out with EDX and XRD. In hydrolysis experiments, the effect of parameters such as molybdenum, NaOH and NaBH4 concentration, catalyst amount and temperature were investigated. The best Mo concentration was found to be 5%. In the presence of the Co–La–Mo–B catalyst in NaBH4 hydrolysis, hydrogen initial production rate was found to be 9508 mL g–1min–1. The activation energy of NaBH4 hydrolyses was determined as 39.5 kJ/mol. The effect of hydrogen gas obtained using the Co–La–Mo–B catalyst in NaBH4 hydrolysis on fuel cell efficiency was determined by measuring I–V values. Average efficiency values according to power and ideal voltage were found as 60 and 80%, respectively. From the results, it can be said that the Co–La–Mo–B catalyst is an ideal catalyst for PEM fuel cell applications.

Hydrogen generation from catalytic hydrolysis of sodium borohydride by a Cu and Mo promoted Co catalyst

Catalytic hydrolysis of chemical hydrides with the use of NaBH4 is a safe and effective way to provide hydrogen fuel for new energy vehicles and portable electronic devices. Herein we developed a Cu and Mo promoted Co hierarchical composites (Co1−xCuxMoO4) for hydrolysis of NaBH4 via an easy synthesis route. FESEM analysis depicts that the morphology of Co1−xCuxMoO4 hierarchical composites varied significantly from irregular microsphere to marigold microsphere to rose like morphology with the increase in Cu (x) ratio with respect to Co (1 − x). Flower-like morphological architecture and crystal configuration empower the supported catalyst to exhibit a remarkable catalytic activity and outstanding catalytic activity was obtained for marigold-like Co0.9Cu0.1MoO4 catalyst with an H2 generation rate of 1005.7 mL min−1 g−1, which confirms existence of synergistic effect between Co, Cu and Mo. Lower loading of Cu in Co1−xCuxMoO4 supported the active sites of Co to increase its catalytic activity. Additionally, the catalyst exhibits good recyclability after five successive runs of hydrolytic reaction, making it a robust catalyst for hydrolysis of NaBH4 and could be considered as a potential catalyst for portable hydrogen fuel systems.

Carbon nanotubes-promoted Co–B catalysts for rapid hydrogen generation via NaBH4 hydrolysis

In this work, multiwalled carbon nanotubes (MWCNTs) promoted Co–B catalysts for NaBH4 hydrolysis have been designed and synthesized. The structural features of as-prepared catalysts have been investigated and discussed as a function of MWCNTs contents by X-ray diffraction, X-ray photoelectron spectra, N2 adsorption/desorption isotherms, scanning electron microscope. The results show that the catalysts still maintain an amorphous structure with the addition of carbon nanotubes promoter. However, the appropriate amount of MWCNTs promoter in Co–B catalysts leads to large specific surface area, fine dispersion of active components, increased active sites and high electron density at active sites. Moreover, hydrogen spillover on the catalyst is promoted, which contributes to regeneration of active sites and accelerating catalytic cycle. Among all the experimental samples, it is found that the Co–B catalyst promoted by 10 wt% carbon nanotubes exhibits optimal catalytic activity with remarkably high hydrogen generation rate of 12.00 L min−1·gcatalyst−1 and relatively good stability.

Graphene modified Co–B catalysts for rapid hydrogen production from NaBH4 hydrolysis

Graphene oxide (GO) modified Co–B catalysts for NaBH4 hydrolysis have been synthesized by the chemical reduction in this work. The structural features and catalytic performance of as-prepared samples have been investigated and discussed as a function of amounts of GO. According to structure characterization, the catalysts still retain the amorphous structure of Co–B alloy with the addition of GO, while GO exists as reduced GO (r-GO). The textural analysis and morphology observation indicate that the appropriate amount of GO in Co–B catalyst results in the obvious increase of specific surface area and uniform clustered morphology, which contributes to improve active surface area for catalytic reactions. The results of surface species characterization show that the electron density at active Co sites increases due to an electron transfer from B to Co facilitated by r-GO. It has been found that 50 mg GO modified Co–B catalyst exhibits especially high activity with a hydrogen generation rate of 14.34 L min−1·gcatalyst−1 and much lower activation energy of 26.2 kJ mol−1 for hydrolysis reaction of NaBH4. Meanwhile, the reusability evaluations show that the catalyst preserves high stability which can still maintain 81.5% of its initial activity after 5 catalytic cycles.

Effective TiO2 supported Cu-Complex catalyst in NaBH4 hydrolysis reaction to hydrogen generation

This paper reports the experimental results on using TiO2 based Cu(II)-Schiff Base complex catalyst for hydrolysis of NaBH4. In the presence of Cu-Schiff Base complex which we reported in advance [1] and with titanium dioxide supports a novel catalyst named TiO2 supported 4-4′-Methylenbis (2,6-diethyl)aniline-3,5-di-tert-buthylsalisylaldimine-Cu complex is prepared, successfully. The synthesized catalyst was characterized by means of X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Brunauer-Emmett-Teller Surface Area Analysis (BET) and Fourier Transform Infrared Spectroscopy (FT-IR). The as prepared catalyst was employed to generate hydrogen through hydrolysis reaction of NaBH4. Effects of different parameters (e.g. amount of Cu-Schiff Base complex in all catalyst, percentage of NaBH4, percentage of NaOH, amount of TiO2 supported Cu-Schiff Base complex catalyst and different temperatures) are also investigated. A high apparent activation energy (Ea), 25,196 kJ.mol-1 is calculated for hydrolysis of NaBH4 at 20–50 °C. Hydrogen generation rate was 14,020 mL H2/gcat.min and 22,071 mL H2/gcat.min in order of 30 °C and 50 °C.

Effective Surface Area Tuning of Noble Metal-Free CuBO2/rGO Nanohybrid for Efficient Hydrogen Production with “On–Off” Switching

Noble metal-free CuBO2/rGO nanohybrid is synthesized and examined as a catalyst for NaBH4 hydrolysis. Detailed characterization reveals that the hybridization generates a charge imbalance between CuBO2 and rGO and creates an electron transport channel which facilitates H2 generation during NaBH4 hydrolysis. High surface roughness, consequently with high effective surface area, is obtained by varying the synthesis conditions. The high activity (specific rate activity, 2500 mL min–1 g–1) and low activation energy (49.8 kJ mol–1) establish this noble metal-free catalyst as a potential candidate in the field of fuel cell based hydrogen economy. The mechanistic investigation confirms that protonation and deprotonation can control the H2 generation kinetics and the same is validated by changing the pH of the reaction medium for an on-site and on-demand H2 production with easy “on–off” switching.

Reaction of Co3O4 Nanocrystals on Graphene Sheets to Fabricate Excellent Catalysts for Hydrogen Generation

The development of functionalized graphene is of significant importance for the application of graphene in solving current energy and environmental problems. In this work, a series of graphene-based hybrid materials including porous graphene (PG) and carbon nanofibers anchored graphene oxide (GCNFs) were synthesized adopting a controllable solid-phase reaction strategy. Co3O4 nanocrystals (NCs) were used as oxidants to modify and adjust graphene sheets. The PG and GCNFs were formed crucially through the red-ox reaction between graphene and Co3O4 NCs during calcinations. As catalyst for NaBH4 hydrolysis at room temperature, CoOx NCs anchored onto PG and CoOx NCs anchored onto GCNFs provided hydrogen generation specific rates of 1472 mL·min–1·gCo–1 and 2696 mL·min–1·gCo–1, respectively. These outstanding catalytic activities are attributed to the synergistic effect of CoOx NCs and PG/GCNFs. A general strategy was proposed for the oxidative cutting and reconstruction of graphene sheets, and the preparation o...

Effect of Al2O3-supported Cu-Schiff base complex as a catalyst for hydrogen generation in NaBH4 hydrolysis

ABSTRACTCu-Schiff base complex which we previously synthesized (Kilinc et al., 2012) is supported on Al2O3. The prepared catalyst is characterized by using SEM, XRD, BET, and FT-IR methods. And Al2O3-supported complex is used as a catalyst in NaBH4 hydrolysis reaction for hydrogen generation. NaBH4 hydrolysis reactions are investigated depending on the concentration of NaBH4 and NaOH, temperature, percentage of Cu complex, and amount of catalyst. Maximum reaction rates are 44,453.33 and 57,410.00 mL H2/g.cat.min at 30°C and 50°C, respectively. The activation energy of NaBH4 hydrolysis reaction is found as 225,775 kJ.mol−1. All the experimental results and literature comparisons show that Al2O3-supported Cu-Schiff base complex is a very effective catalyst in NaBH4 hydrolysis for H2 generation.

Monolithically integrated NiCoP nanosheet array on Ti mesh: An efficient and reusable catalyst in NaBH4 alkaline media toward on-demand hydrogen generation

In this work, we demonstrate the first use of NiCoP nanosheet array on Ti mesh (NiCoP NA/Ti) as an efficient catalyst for hydrolysis of NaBH4 in alkaline media. This catalyst shows a low activation energy of 52.68 kJ/mol for NaBH4 hydrolysis meanwhile the hydrogen generation rate can achieve 3016.79 mL/min/g(NiCoP) at 303 K, outperforming most reported Co-based noble-metal-free catalysts and some noble-metal catalysts. Remarkably, the catalyst exhibits high recyclability, durability and controllability for on-demand hydrogen generation in alkaline NaBH4.

Kinetic properties of co-reduced Co-B/graphene catalyst powder for hydrogen generation of sodium borohydride

The aim of the present work is to investigate the kinetic properties of Co-B nanoparticles which are deposited on graphene sheets by simultaneous chemical reduction of Co+2 and graphite oxides using NaBH4 as the reducing agent. The reduced Co−B/graphene nanocomposites were characterized by X-ray diffraction, and the effects of the concentration of NaBH4, NaOH, and hydrolytic temperature were discussed in detail. The results show that the concentration of NaBH4 and NaOH indeed exerted a significant impact on the hydrogen generation rate of Co-B/graphene catalysts. Reaction rate of hydrolysis first rises up and then decreases subsequently with the rising of NaOH and NaBH4 concentration. The results show that the Co-B/graphene catalyst has the high catalytic activity with activation energy of 52.45 kJ·mol−1, and showed high resistance against deterioration and stability as a function of time. The present method is promising for the synthesis of effective supported catalysts for hydrolysis of NaBH4.

Synthesis of Ni/Au/Co trimetallic nanoparticles and their catalytic activity for hydrogen generation from alkaline sodium borohydride aqueous solution

Alloyed Ni/Au/Co nanoparticles with negatively-charged Au, Co atoms, and positively-charged Ni atoms were prepared as effective catalysts for hydrolysis of NaBH4.

New electroless plating method for preparation of highly active Co–B catalysts for NaBH4 hydrolysis

Supported non-noble transition metal catalysts are ideal for use in NaBH4-based hydrogen storage systems because of their low cost, robustness, and ease of handling. We have developed a new low-temperature electroless plating method for preparation of Co–B catalysts supported on Ni foam. This method requires only one plating step to achieve the desired catalyst loading, and has higher loading efficiency than conventional multi-step methods. The produced Co–B catalyst shows higher NaBH4 hydrolysis activity than those prepared by conventional methods due to increased boron content and nanosheet-like morphology. The pH and NH3 concentration of the precursor solution were found to have considerable influences on both the catalyst loading and activity. Temperature dependence of hydrogen generation suggests that the catalytically active phase is formed in situ above a certain temperature threshold, which is supported by XPS analysis. The maximum specific hydrogen generation rate is in excess of 24,000 mL min−1 g−1, which is among the highest values for catalysts of this type reported in the literature.

Synthesis of graphene-based Co-B catalyst via simultaneous chemical reduction for hydrolysis of sodium borohydride

Co-B nanoparticles are deposited on graphene sheets by simultaneous chemical reduction of Co+2 and graphite oxides using NaBH4 as the reducing agent. The reduced Co−B/graphene nanocomposites were characterized by X-ray diffraction, Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The results show that after reduction, not only considerable amount of functional groups has been removed but also exhibited formation of Co-B alloy on the graphene sheets. The catalytic activity of nanocomposites was investigated by the hydrolysis of NaBH4 in aqueous solution. Graphene support material greatly enhances the hydrolysis of NaBH4 with respect to graphite and active carbon supports, and chemical reduced graphene sheets can readily form stable aqueous colloids through electrostatic stabilization. The present method is promising for the synthesis of effective supported catalysts for hydrolysis of NaBH4.

Microwave-Assisted Synthesis of Ni/CNTs Nanocomposites for Hydrogen Production from Hydrolysis of NaBH<sub>4</sub>

Hydrogen production from NaBH4 hydrolysis is very important for environment-friendly fuel cells. Here Ni/CNTs nanocomposites were prepared by microwave-assisted method and used as the catalyst for catalytic hydrolysis of NaBH4. XRD and SEM characterization showed that uniform Ni/CNTs nanocomposites can be obtained through microwave heating and solvent optimization. Ni/CNTs nanocomposites exhibit excellent catalytic activity in the hydrolysis of NaBH4, i.e., the average hydrogen generation rate at 25°C is 840ml.min-1.g-1 for the CNTs-supported Ni/CNTs, while the hydrogen generation rate of 86ml.min-1.g-1 for unsupported Ni catalyst. Compared with the unsupported Ni catalyst, Ni/CNTs nanocomposites presented higher catalytic activity for hydrolysis of aqueous NaBH4 solution.