Co-B Catalyst Research Articles

Molecular dynamics approach to efficient hydrogen generation process of Co-B catalysts decorating lanthanides (La, Ce, Pr, Nd) supported by flat-sheet and twisted ThMoB4-type graphene from NaBH4 hydrolysis: Insights from non-self-consistent GFN1-xTB method

In this study, the promoter role on highly efficient hydrogen generation productivity and H2 formation mechanisms of Co-B-X catalysts modified by rare earths (X = La, Ce, Pr, Nd) supported by flat-sheet and twisted ThMoB4-type graphene from sodium borohydride (NaBH4) hydrolysis was investigated using molecular dynamics (MD) method based on non-self-consistent tight binding GFN1-xTB Method. The twisted ThMoB4-type graphene layer was constructed by adsorbing of ethylene carbonate (EC) molecule on armchair site of graphene surface with applying of geometric optimization process. The addition of Nd to CoB exhibited to higher H2 release compared to other CoB containing lanthanides (La, Ce and Pr) both flat-sheet and twisted ThMoB4-type graphene. While the number of H2 for Co-B-Nd is 14, the H2 amount is only 8 for Co-B-Ce supported flat-sheet graphene at the end of simulation time. Also, the placing of twisted graphene instead of flat-sheet in the catalytic complex led to about 36 % increase in H2 number for Co-B-Nd. The computational results revealed that the availability of the active sites, such as basicity of catalytic environment related to OH and H species and the mobility of Co atom, played an important role for catalytic activity and performance for H2 production. This work can provide new insight for experimental studies of Co-B-X (X = La, Ce, Pr, Nd) catalysts for hydrogen production in atomic-level and the creation of new hydrogen energy applications and facilitates for H2 generation efficiency.

Selective synthesis of oxygenated fuel derivative from microwave assisted acetalization of glycerol: Optimization and mechanistic investigations

Glycerol contains 52 wt% oxygen content, therefore unable to be directly used as fuel due to its poor combustion ability. Thus, the catalytic conversion of glycerol into various oxygen-containing fuel additives is grabbing more attention nowadays. This work provides a novel, sustainable, and eco-friendly method for synthesizing heterogeneous acid carbon catalysts from pearl millet cob (PMC) waste. The hydrothermal carbonization process was carried out at different temperatures to fabricate the series of sulfonated pearl millet cob (SPMC) catalysts. XRD, FT-IR, SEM-EDS, XPS, BET, TGA, and CHNSO analyses were performed to characterize fabricated catalysts. The synthesized catalyst, SPMC-70 (catalyst synthesized at 70 °C temperature), possesses OH, COOH, and SO3H functional groups and a significant total acid density (2.03 mmol/g) with 37 m2/g surface area. The SPMC catalysts were employed for the microwave-assisted acetalization reaction of glycerol with acetone for solketal production. The optimization process was carried out using various reaction parameters, including catalyst dosage (2–6 wt.%), reaction temperature (30–60 °C), glycerol to acetone (GL to AC) molar ratio (1:3–1:9), and reaction time (4–13 min). The SPMC-70 catalyst showed the highest catalytic activity among all the synthesized catalysts and provided 99.11 ± 0.3 % GL conversion with 100 % selectivity of solketal under optimal reaction conditions. Additionally, the recyclability test was performed, and it found that the best catalyst was reusable for up to five reaction cycles. These results showed the effectiveness of carbon-based heterogeneous acid catalysts in deriving a fuel additive, solketal.

Enhancing the efficiency of sodium borohydride hydrolysis with a novel CoB-Triton catalyst

Hydrogen is increasingly recognized as the most significant alternative solution for reducing global greenhouse gas emissions in maritime transportation. In particular, solid-state sodium borohydride (NaBH4) with its high hydrogen storage density stands out as the preferred choice due to its higher efficiency and improved safety. In present study, a surfactant-stabilized CoB catalyst was used in order to improve the hydrolysis performance of NaBH4. For this reason, the effects of Triton X-100, used as a surfactant in different quantities, on the hydrogen generation rate were tested. To characterize the prepared samples, several analytical techniques were employed, including field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), Mastersizer analysis, X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. According to findings, 40.2% faster hydrogen generation rate is obtained with CoB-Triton 150 contrary to CoB catalyst. The optimum concentrations are found as 5% NaOH and 5% NaBH4 and activation energy is 44.21 kj/mol for developed CoB-Triton 150 catalyst. Last of all, fuel cell performances show that the produced hydrogen from hydrolysis reaction through CoB-Triton 150 catalyst has nearly same fuel cell performance compared to industrial pure hydrogen. Consequently, Triton X-100 is a good candidate to improve the hydrolysis performance of NaBH4 and needs further research.

Mesoporous Ru(Co, Ni)B bimetallic amorphous alloy for CO2 hydrogenation to formic acid

Amorphous metal alloy catalysts have attracted even-increasing attention owing to their high activity and selectivity. However, they are mainly prepared in ultrafine nanoparticles, which are easily gathered and challenging to separate. In this work, mesoporous Ru(Co, Ni)B bimetallic amorphous alloy catalysts with magnetic properties that can be easily recovered were synthesized via surfactant self-assembly. The as-prepared Ru1%CoB catalyst exhibited 578 μmol/g/h production rate and 99% selectivity to HCOOH during liquid phase CO2 hydrogenation owing to the unique amorphous alloy structure corresponding to the well-distributed, coordination-unsaturated, electron-enriched and synergistic active sites, which promoted the adsorption, activation, dissociation, and surface reaction of CO2 and H2. Moreover, the mesoporous channels also promoted the diffusion and adsorption of CO2 and H2. Besides, the Ru1%CoB catalyst also displayed good durability in CO2 hydrogenation owing to the robust stability against the crystallization of amorphous alloy, the collapse of mesopores, and the leaching of active sites.

Investigation on the effect of synthesizing temperature on the catalytic activity of nickel cobalt boron catalysts in sodium borohydride hydrolysis process

Hydrogen production through the reaction between sodium borohydride (NaBH4) and water in presence of three different catalysts including; NiB, CoB and NiCoB is studied. The catalysts are synthesized by chemical reduction method at room and 0 °C temperature. The products are characterized by X-Ray Diffraction (XRD), High-Resolution Scanning Electron Microscopy (HRSEM) and Inductively Coupled Plasma-optical emission spectroscopy (ICP). The results showed that carrying out synthesizing process at low temperature, causes decreasing the nuclei size and reducing driving force for the growth stage, and results in a meaningful reduction in size of the produced catalysts particles. Furthermore, it leads to a recognizable change in particles shape to fine spherical with definite boundaries and slightly increase in boron content of each catalyst. These changes, especially in size and shape of the produced catalysts, results in an improvement in catalytic activity of the synthesized catalysts and the rate of hydrogen generation through using them. This achievement were successfully proved for all three NiB, CoB and NiCoB catalysts, although it was more pronounced for CoB so that it was possible to produce 1.4 lit hydrogen in less than 13 s (12,923 ml·min−1.g−1catalyst) by using 0.5 g of CoB catalyst synthesized at 0 °C.

Effects of various metal doping on the structure and catalytic activity of CoB catalyst in hydrogen production from NaBH4 hydrolysis

Four ternary alloy CoB-based catalysts, including Co-Sn-B, Co-Mn-B, Co-Cr-B and Co-Bi-B, were prepared by chemical reduction method.The effect of Sn, Mn, Cr and Bi dopants on phase structure, surface morphologies, electronic interaction, catalytic activity and activation energies of CoB catalysts investigated in depth. Their catalytic activity in hydrogen production from NaBH4 hydrolysis was compared systematically. Compared with undoped CoB catalyst, it can be found that the doping of Cr and Bi exhibits a significant promoting effect on CoB catalyst by accelerating hydrogen generation rate. Nevertheless, the introduction of Sn and Mn into CoB catalyst only attains a slight increase in hydrogen production rate. The doping concentration of Sn, Mn, Cr, Bi species in CoB was adjusted to respectively check their phase structure and catalytic performance, indicating that there is an optimum doping concentration for each dopant. It can be concluded that the promoting effect of various dopants on catalytic performance can be attributed to crystalline phase, specific surface area and electronic interaction involved in NaBH4 hydrolysis.

Synthesis of “needle-cluster” NiCo2O4 carbon nanofibers and loading of Co-B nanoparticles for hydrogen production through the hydrolysis of NaBH4

Hydrogen production through chemical processes has received considerable attention. Replacing precious-metal-based catalysts in NaBH4 hydrolysis entails challenges such as the low durability and efficiency of non-precious metals. Here, carbon nanofiber (CNF)-supported NiCo2O4 and CoB were synthesized to form a burr-shaped rod-like catalyst (CNF-NiCo2O4-CoB). The morphology and microstructure of the catalyst were characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller adsorption analysis. Then, NaBH4 hydrolysis was catalyzed using CNF-NiCo2O4-CoB. At 303 K, the hydrogen production rate and activation energy of the hydrolysis reaction were 5225 mL min−1 g−1 and 38.32 kJ mol−1, respectively. The maximum hydrogen production rate achieved using this composite catalyst was significantly higher than that of a pure CoB catalyst. The composite catalyst also exhibited high durability, maintaining 82.5% of its initial catalytic activity even after nine hydrolysis cycles. The magnetic nature of the catalyst improved its recyclability. This work provides a new method for synthesizing composite-structured catalysts, exhibiting considerable potential in the hydrolysis of NaBH4.

A hydrogen generator coupled to a hydrogen heater for small scale portable applications

This study aims to build and test a small scale portable device able to couple a hydrogen generation system (based on a NaBH4 solution as liquid H2 carrier) to a hydrogen heater (based on the exothermic catalytic combustion of the released H2). The hydrogen generating system is based on the hydrolysis of stabilized solutions of NaBH4 (fuel solutions) which are pumped into the hydrolysis reactor. The generated H2 feeds the catalytic combustor. Two catalysts have been developed for the H2 generation and the combustion reactions able to operate at room temperature without need of additional energy supply. For the NaBH4 hydrolysis a Co-B catalyst was supported on a perforated and surface treated stainless steel (SS316) home-made monolith. For the flameless H2 catalytic combustion a Pt catalyst was prepared on a commercial SiC foam. The device was automatized and tested for the on-demand production of heat at temperatures up to 100ºC. In steady state conditions the NaBH4 solution flow is controlling the H2 flux and therefore the heater temperature. Once the steady-state is reached the system responds in a few minutes to up and down temperature demands from 80 to 100 ºC. The catalysts have shown no deactivation during the tests carried out in several days.

Preparation of CoB nanoparticles decorated PANI nanotubes as catalysts for hydrogen generation from NaBH4 hydrolysis

Magnetic agglomeration of CoB nanoparticles in the hydrogen production from the hydrolysis of NaBH4 aqueous solution always degrades their catalytic activity. This work aims at the rational development of robust supported CoB catalyst that is active and stable towards NaBH4 hydrolysis. In this study, PANI nanotubes derived from PS nanofiber templates are firstly synthesized by the polymerization of aniline followed by the template removal. CoB nanoparticles are then decorated into PANI nanotubes via an impregnation and chemical reduction method. It can be found that CoB nanoparticles can be confined into the internal surface of PANI nanotubes which improves the dispersion and anchored stability of CoB nanoparticles. The as-prepared CoB/PANI composite catalyst exhibits a high catalytic performance and recycling stability. The hydrogen production rate as high as 2300 ml. min−1. g − 1 is achieved and the activation energy was calculated to be only 37.75 kJ/mol. Meanwhile, CoB/PANI catalyst displays excellent stability in NaBH4 hydrolysis during five cycles. The experimental results indicated that as-synthesized CoB/PANI composite catalysts are very efficient towards hydrogen production from NaBH4 hydrolysis.

Recent Advances in Applications of Co-B Catalysts in NaBH4-Based Portable Hydrogen Generators

This review highlights the opportunities of catalytic hydrolysis of NaBH4 with the use of inexpensive and active Co-B catalysts among the other systems of hydrogen storage and generation based on water reactive materials. This process is important for the creation of H2 generators required for the operation of portable compact power devices based on low-temperature proton exchange membrane fuel cells (LT PEM FC). Special attention is paid to the influence of the reaction medium on the formation of active state of Co-B catalysts and the problem of their deactivation in NaBH4 solution stabilized by alkali. The novelty of this review consists in the discussion of basic designs of hydrogen generators based on NaBH4 hydrolysis using cobalt catalysts and the challenges of their integration with LT PEM FC. The potential of using batch reactors in which there is no need to use aggressive alkaline NaBH4 solutions is discussed. Solid-phase compositions or pellets based on NaBH4 and cobalt-containing catalytic additives are proposed, the hydrogen generation from which starts immediately after the addition of water. The review made it possible to formulate the most acute problems, which require new sci-tech solutions.

Optimization of Hydrogen Generation by Catalytic Hydrolysis of NaBH4 with Halloysite-Supported CoB Catalyst Using Response Surface Methodology

AbstractThe hydrolysis of sodium borohydride (NaBH4) is a promising reaction with a possible practical application as a means of generating hydrogen. The efficiency of hydrogen production can be enhanced significantly by use of a catalyst during the reaction. Cobalt borides show significant catalytic activity, but unsupported CoB particles aggregate easily and are difficult to separate from the reaction medium for re-use. The objectives of the present study were to use halloysite (Hly) as a support material to increase the catalytic activity and reusability of a Co metal-based system and to investigate the binary effect of metal loading and reaction parameters on the hydrolysis of NaBH4. Catalysts were prepared by wet impregnation and chemical reduction. The surface morphology and structural properties of the prepared catalysts were characterized using N2 adsorption-desorption and the Brunauer-Emmet-Teller (BET) method, field emission scanning electron microscopy (FE-SEM), with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICP-MS). Response surface methodology (RSM) was used to optimize metal loading and reaction conditions for the hydrogen-generation rate. Optimum reaction conditions were determined (using Design Expert 7.0 software) as 5.01 wt.% Co loading using a Co-B/Hly-supported catalyst, 0.44 M NaBH4, 10.66 mg catalyst, and at a reaction temperature of 39.96°C. The maximum hydrogen generation rate was 33,854 mL min−1 gCo−1 under these conditions.

Effects of blast furnace slag (BFS) and cobalt-boron (Co-B) on hydrogen production from sodium boron hydride

In the present paper, the blast furnace slag (BFS) supported Co-B catalyst were investigated in detail. The impregnation-chemical reduction method was used while hydrochloric (HCl) acid treated BFS samples (BFS+) were prepared. Catalyst samples were analyzed in three main groups as base BFS (BFS0), BFS0-Co-B and BFS+-Co-B. The effects of these catalyst samples on hydrogen production from the solid-state sodium boron hydride (NaBH4) are analyzed in this study. The effects of some parameters such as the ingredients of blast furnace slag, the molarity of hydrochloric acid treatment, the Co percentages and the solution temperatures were investigated on the hydrolysis performance of NaBH4. The NaBH4 hydrolysis reaction with the BFS0 is treated by the BFS+-Co-B-20% catalyst was completed approximately 25 min and the hydrolysis reaction with the BFS0-Co-B-20% catalyst was completed approximately 20 min whereas the hydrolysis reaction of NaBH4 was completed in 1 h 35 min. The hydrogen production rates at pre-heated to max 40, 50 and 60 °C were measured as 55.12, 64.47 and 70.41 L/min.gcatalyst, respectively. According to another result of the study, the high-efficiency solid-state BFS-Co-B & NaBH4 mixtures were covered with the PVA (Polyvinyl alcohol) film to make them more resistant to environmental effects such as humidity.

Cobalt loaded organic acid modified kaolin clay for the enhanced catalytic activity of hydrogen release via hydrolysis of sodium borohydride

Inorganic acids such as hydrochloric acid (HCl), nitric acid (HNO3) and sulphuric acid (H2SO4) are generally used in the acid modification of clays. Here, CoB catalyst was synthesized on the acetic acid-activated kaolin support material (CH3COOH -kaolin- CoB) with an alternative approach. This prepared catalyst, firstly, was used to catalyze the hydrolysis of NaBH4 (NaBH4-HR). The structure of the raw kaolin, kaolin-CH3COOH, and CH3COOH-kaolin-CoB samples were characterized by X-ray diffraction spectroscopy (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscope (SEM), and nitrogen adsorption. At the same time, this catalyst performance was examined by Co loading, NaBH4 concentration, NaOH concentration, temperature and reusability parameters. The end times of this hydrolysis reaction using raw kaolin-CoB and CH3COOH-kaolin-CoB were found to be approximately 140 and 245 min, respectively. The maximum hydrogen generation rates (HGRs) obtained at temperatures 30 °C and 50 °C were 1533 and 3400 mL/min/gcatalyst, respectively. At the same time, the activation energy was found to be 49.41 kJ/mol.

Hydrogen production through hydrolysis of sodium borohydride: Highly dispersed CoB particles immobilized in carbon nanofibers as a novel catalyst

Agglomeration of CoB catalysts is a severe problem in hydrogen generation from NaBH4 hydrolysis. Herein, highly dispersed carbon nanofiber immobilized CoB catalysts (CoB/CN) were synthesized by a combined prereduction and carbonization method, which is used in hydrogen generation from NaBH4 hydrolysis. Morphological evolution of carbon nanofibers, phase structure and elemental distribution of CoB/CN catalysts are explored by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Compared to Co/carbon nanofiber catalysts (Co/CN) without prereduction, CoB/CN catalysts can afford higher CoB dispersity and specific surface area because the migration rate of cobalt species during carbonization is effectively retarded by prereduction. Hence the agglomeration of magnetic CoB nanoparticles can be effectively inhibited. The hydrogen generation experiment shows that CoB/CN catalysts process higher catalytic activity and lower activation energy than Co/CN.

Preparation of CoB catalysts supported on raw and Na-exchanged bentonite clays and their application in hydrogen generation from the hydrolysis of NaBH4

The aim of this work is to prepare CoB catalysts supported on raw bentonite (CoB/bentonite) and Na-exchanged bentonite (CoB/Na-bentonite) by the impregnation and chemical reduction method. The prepared catalysts were characterized using X-ray diffractometry (XRD), X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) techniques. The activities of the catalysts were tested in the hydrolysis reaction of sodium borohydride (NaBH4) in a semi-batch system. The volume of the evolved hydrogen gas was determined by a water displacement method. The effects of catalyst amount, NaOH (a base stabilizer) concentration, NaBH4 concentration and solution temperature on the hydrogen generation rate were investigated. The maximum hydrogen generation rates were determined as 921.94 mL/min.gcat for CoB/bentonite and 1601.45 mL/min.gcat for CoB/Na-bentonite when the 5 wt % NaBH4 and 10 wt % NaOH solutions were used at 50 °C. The activation energies (Ea) of the hydrolysis reaction over CoB/bentonite and CoB/Na-bentonite were determined as 55.76 and 56.61 kJ/mol, respectively.

Understanding the role of boron and stoichiometric ratio in the catalytic performance of amorphous Co-B catalyst

The structural, electronic and hydrogen adsorption properties of amorphous CoB, Co2B and Co3B structures were investigated using first principle calculations to evaluate their catalytic activity for HER. A total of eight different sites were considered for hydrogen adsorption, of which the threefold site with two Co and single B atom (TF-2Co-B) was found to be most active site for all the three amorphous Co-B structures. The B atom donates electronic charge to the Co-B bond, while, the presence of Co atom is responsible for achieving the optimal charge density necessary for favorable hydrogen adsorption. This interaction between the Co and B atoms makes bonding region between the Co and B atoms most favorable for hydrogen adsorption and not lone Co atom nor the B atom, thus, determining the active sites of Co-B catalyst. The best catalytic behavior of Co2B stoichiometry was credited to the perfect balance of magnetic properties, optimum hydrogen adsorption energies and considerable number of active sites it displayed.

HYDROGEN GENERATION BY HYDROLYSIS OF NaBH4 WITH EFFICIENT Co-La-W-B CATALYST FOR PEM FUEL CELLS

In this study, Co-B based quaternary alloy catalysts were synthesized for use in NaBH4 hydrolysis. Lanthanum (La) and tungsten (W) metals were added to Co-B catalyst by chemical reduction method. The effect of metal content (La and W), NaBH4 concentration, NaOH concentration, catalyst amount and temperature parameters were investigated in NaBH4 hydrolysis. Activity results show that the hydrolysis reaction rate first increases and then decreases with increasing NaBH4 concentration as well as NaOH concentration. The activation energy of the hydrolysis for Co-La-W-B catalysts was calculated as 39.2 kJ / mol. The maximum value of hydrogen generation rate was 3280 ml / min. In terms of application, hydrogen produced in the presence of the Co-La-W-B catalyst was used in PEM fuel cell application. Average yield value according to power and ideal voltage and maximum power vaşue of the system were determined as 57%, 73% and 1.4 Watt, respectively. This original study demonstrates that the Co-La-W-B catalyst can be used as an ideal catalyst for PEM fuel cell applications.

Spirulina Platensis microalgae strain modified with phosphoric acid as a novel support material for Co–B catalysts: Its application to hydrogen production

Spirulina platensis is defined as the dried biomass of cyanobacteria in commercial use and is biomass with high carbon content. Spirulina platensis microalgae strain supported-CoB catalysts to produce hydrogen from sodium borohydride (NaBH4) were prepared for the first time. The Spirulina platensis microalgae strain was modified with phosphoric acid (H3PO4) to proton. Then, the supported catalyst was performed to produce hydrogen from NaBH4 hydrolysis. The optimum H3PO4 concentration, optimum Co amount, and optimum impregnation time of the H3PO4 with the microalgae strain were investigated. The maximum hydrogen production rate for the 30% CoB catalyst supported on microalgae strain treated with H3PO4 was found to be 3940 mL min−1g−1catalyst. X-ray powder diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), and scanning electron microscope (SEM) analysis were performed for characterization of CoB catalyst supported on Spirulina microalgae strain. After four consecutive uses, the performance and conversion values of this catalyst were investigated. At the same time, the effect of temperature on the hydrogen production from this hydrolysis reaction was examined. The activation energy with the CoB catalyst supported on Spirulina microalgae strain was calculated as 35.25 kJ mol−1. According to the kinetic model of a power law, n value was found as 0.25 for kinetic studies.

A unique amorphous cobalt-phosphide-boride bifunctional electrocatalyst for enhanced alkaline water-splitting

A unique cobalt-phosphide-boride (Co-P-B) catalyst was synthesized via simple chemical-reduction route. The obtained catalyst was amorphous in nature, resembling the spherical morphology of Co-B nanoparticles. X-ray photoelectron spectroscopy revealed that B loses electrons to Co while P gains electrons from Co. This unique electron transfer mechanism in Co-P-B is a combination of the characteristics showcased by Co-B and Co-P catalysts individually. The optimized catalyst (Co-P-B-5) showed overpotentials of 145 mV and 290 mV to achieve the benchmark current density of 10 mA/cm2 for HER and OER, respectively, in 1 M NaOH. From theoretical calculations, it was observed that addition of P modulates the electron density at Co sites, thereby optimizing the H-adsorption capability, leading to higher HER rate. During anodic polarization, Co-P-B-5 shows formation of large number of CoOOH species on its surface, facilitating OER. Finally, stability, recyclability and wide-pH suitability of Co-P-B-5 was established to demonstrate its industrial viability.

Optimisation of sepiolite clay with phosphoric acid treatment as support material for CoB catalyst and application to produce hydrogen from the NaBH4 hydrolysis

Herein, the CoB catalyst supported on the sepiolite clay treated with phosphoric acid was utilized to produce hydrogen from the NaBH4 hydrolysis. In order to analyse the performance of the phosphoric acid treated sepiolite clay supported-CoB catalyst, the NaBH4 concentration effect, phosphoric acid concentration effect, phosphoric acid impregnation time effect, CoB catalyst percentage effect, and temperature effect were studied. In addition, XRD, XPS, SEM, TEM, BET, and FTIR analysis were performed for characterization of Co–B catalyst supported on the acid-treated sepiolite. The completion time of this hydrolysis reaction with Co–B (20%) catalyst supported on the sepiolite treated by 5 M phosphoric acid was approximately 80 min, whereas the completion time of this hydrolysis reaction with acid-free sepiolite-supported Co–B (20%) catalyst was approximately 260 min. There is a five-fold increase in the maximum production rate. The maximum hydrogen production rates of this hydrolysis reaction at 30 and 60 °C were found as 1486 and 5025 ml min−1g−1catalyst, respectively. Activation energy was found as 21.4 kJ/mol. This result indicates that the acid treatment on sepiolite is quite successful. The re-usability of NaBH4 hydrolysis reaction by CoB catalyst supported on sepiolite treated phosphoric acid for successive five cycles of NaBH4 at 30 °C was investigated.