Hydrolysis Of Borohydride Research Articles

Co-CeOx nanoparticles anchored on a nitrogen-doped carbon nanosheet: a synergistic effect for highly efficient hydrolysis of sodium borohydride

Amorphous and electron-rich Co-CeOx nanoparticles anchored on a N-doped porous carbon nanosheet show remarkable catalytic performance for the hydrolysis of sodium borohydride.

Calculating the adsorption energy of a charged adsorbent in a periodic metallic system - the case of BH4- hydrolysis on the Ag(111) surface.

The hydrolysis of borohydride on the Ag(111) surface is explored theoretically to obtain the in-depth reaction mechanism. Many heterogeneously catalyzed reactions like this involve the adsorption of charged species on metals. DFT calculations of charged systems, with periodic boundaries, face serious problems, concerning convergence and reliability of the results. To study the heterogeneously catalyzed reactions, a simple method to calculate the adsorption energy of charged systems in metallic periodic cells is proposed. In this method, a counter ion is placed at a non-interactive distance, in an aqueous medium, so that the calculated system is neutral. Bader analysis is used to validate that the calculated couple is charged correctly. Adsorption energies of F-, Cl-, Br-, OH-, BH4-, ClO4- and H- ions on the Ag(111) surface in an aqueous medium were determined using Na+ and K+ as counter ions, to evaluate the performance of this method. The adsorption of the divalent ions S2-, Se2- and SO42- on different surfaces was studied as well. Then this method was used to explore the hydrolysis of BH4- ions, which have a high theoretical hydrogen storage capacity, on the Ag(111) surface. The results point out that during the catalytic hydrolysis only one hydrogen atom from borohydride is transferred to the surface. In the first step one hydrogen atom from BH4- is transferred to the silver surface; this H atom reacts with a hydrogen atom that is released from an adsorbed water molecule; in addition, a hydrogen molecule is released in the second step (one atom from *BH4- and one from *H2O). Thus, the mechanisms of the catalyzed reductions by BH4- and the hydrogen evolution reactions must be reconsidered.

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.

Partial inhibition of borohydride hydrolysis using porous activated carbon as an effective method to improve the electrocatalytic activity of the DBFC anode

Utilization of activated carbons from coffee waste in the complex borohydride electrooxidation process has great potential in increasing the efficiency of an anode based on the AB5-hydrogen storage alloy, as well as in proper management of waste.

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.

Synthesis of Ni/TiO2 catalyst by sol-gel method for hydrogen production from sodium borohydride

Hydrogen is a sustainable, renewable and clean energy carrier that meets the increasing energy demand. Pure hydrogen is produced by the hydrolysis of sodium borohydride (NaBH4) using a catalyst. In this study, Ni/TiO2 catalysts were synthesized by the sol-gel technique and characterized by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) methods. The effects of Ni loading ratio (20–40%), catalyst amount (75–200 mg), the concentration of sodium hydroxide (NaOH, 0.25–1 M), initial amount of NaBH4 (75–125 mg) and the reaction temperature (20–60 °C) on hydrogen production performance were examined. The hydrogen yield (100%) and hydrogen production rate (110.87 mL/gcat.min) were determined at the reaction conditions of 5 mL of 0.25 M NaOH, 100 mg NaBH4, 100 mg Ni/TiO2, 60 °C. Reaction order and activation energy were calculated as 0.08 and 25.11 kJ/mol, respectively.

Optimization of synthesis parameters for catalytic performance of Ni–B catalysts using response surface methodology

Hydrogen production through hydrolysis of sodium borohydride (NaBH4) by using metal catalysts is promising for fuel cell applications. Nickel (Ni) and its alloys are favorable due to their high catalytic activity, relatively low cost and availability. In present study, the effects of temperature, pH, reduction rate and reducing agent concentration, which significantly affect the catalyst performance, were investigated using the response surface methodology (RSM). A mathematical model was derived according to results which were obtained from four-level orthogonal Taguchi L16 (44) experimental design used for the optimization of multiple parameters in the process. From the RSM analyses, that compatible with the predicted experimental results, maximum hydrogen generation rate (HGR) 49.81 L min−1 gcat−1 was obtained temperature of 278.12 K, pH of 5.52, reducing agent concentration of 85.96 NaBH4.water−1 and reduction rate of 6.82 mL min−1. Analysis of variance reveals that both pH and rate of reduction have significant effect than the temperature on the HGR.

Solid-state NaBH4 composites for hydrogen generation: Catalytic activity of nickel and cobalt catalysts

Hydrogen generation from tablets of sodium borohydride with chlorides of nickel and cobalt was studied. The nickel catalysts were shown to be less active in the borohydride hydrolysis than the cobalt catalysts. One of the reasons for the lower activity of the nickel catalyst was the presence of hydrogen on its surface, which hampered the adsorption of reactants. The addition of cobalt to the nickel catalyst increases the hydrogen generation rate. This is due to the introduction of active metal with low adsorption capacity for hydrogen and the higher dispersion of the active component.

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.

Oxalic Acid Promoted Hydrolysis of Sodium Borohydride for Transition Metal Free Hydrogen Generation

Oxalic Acid Promoted Hydrolysis of Sodium Borohydride for Transition Metal Free Hydrogen Generation

Cobalt Boride Graphene Composites As a Novel Catalyst for Hydrogen Evolution

Carbon allotropes like carbon nanotubes and graphene like materials are useful for improving the catalytic ability of transition metals.1 These materials are notable for structural stability and high surface area for the dispersion of catalyst.2 This study explored a novel cobalt catalyst supported on graphene like materials CoB@G for the hydrolysis of sodium borohydride (NaBH4). Sodium borohydride is a hydrogen feedstock material (HFM) that contains 10.8% hydrogen by weight and reacts in water.3 This makes it a choice material for the generation of hydrogen gas; however, this react occurs slowly. CoB@G was synthesized from the reduction of a cobalt metal organic framework (MOF) supported on graphene oxide (CoMOF-5@GO). Hydrolysis of NaBH4 was conducted at temperatures of 283K-303K. Compared to bulk metals: nickel, cobalt, and raney nickel, our catalyst had a great activation energy of 54 kJ mol-1.4 Our product was characterized with Powder X-Ray Diffraction (P-XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM, Figure 1), Energy Dispersive X-Ray Spectroscopy (EDS), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), and Transmission Electron Microscopy (TEM). This product also should good reusability, producing similar amounts of hydrogen after 5 consecutive trials. The hydrolysis of sodium borohydride using our novel catalyst will aid in the mass production of hydrogen for use as an alternative energy source.Works Cited: Huff, C., Dushatinski, T., & Abdel-Fattah, T. M.. Gold nanoparticle/multi-walled carbon nanotube composite as novel catalyst for hydrogen evolution reactions. International Journal of Hydrogen Energy (2017) 42(30), 18985 18990.doi:10.1016/j.ijhydene.2017.05.226Machado, B. F.; Serp, P. Graphene-Based Materials for Catalysis. The Royal Society of Chemistry 2011, 43 (13), 54–75.Schlesingehr H.I.; Brown, H.C.; Finholt A.E.; Gilbreath J.R.; Hoekstra H.R.; Hyde E.L.; Sodium Borohydride, Its Hydolysis and its Use as a Reducing Agent in the Generation of Hydrogen; Chem. Soc., (1953), 75 (1), pp 215–219Kaufman, C. M., & Sen, B. (). Hydrogen generation by hydrolysis of sodium tetrahydroborate: effects of acids and transition metals and their salts. Journal of the Chemical Society, Dalton Transactions, 1985 (2), 307. doi:10.1039/dt9850000307 Figure 1: Graphene supported cobalt borides are shown with SEM imaging. The graphene sheets formed large structures, some of which were over 100 microns in length Figure 1

Reduction of Mn-MOF-5 Supported on Graphene As a Catalyst for Hydrolysis of Sodium Borohydride

Metal borides are a class of catalyst that are known for their stability, high conductivity, and excellent catalytic capabilities.1 These materials may be an efficient catalyst for the hydrolysis of water to produce hydrogen gas. Hydrogen is the most abundant element in the universe and highly sought after for a clean burning, alternative fuel. Issues associate with storing compressed H2 gas has turned the focus to generating H2 from a hydrogen feedstock material (HFM). One such HFM known as sodium borohydride (NaBH4) contains 10.8% hydrogen by weight and reacts with water to produce H2 gas.2 Our group developed a novel method of synthesizing Manganese borides supported on graphene like materials (MnB@G) to catalyze the hydrolysis of sodium borohydride. Our group chose graphene as a support since previous work within this team showed that carbon allotrope supports can increase the catalytic capability of metal catalysts3,4. Our materials were prepared from the reduction of a manganese metal organic framework (MOF) supported on graphene oxide (MnMOF-5@GO) at room temperature (RT 295K). These metal borides were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Powder X-Ray Diffraction (P-XRD), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), Transmission Electron Microscopy (TEM), Energy Dispersive X-Ray Spectroscopy (EDS), and Scanning Electron Microscopy (SEM, Figure 1) before they were tested for hydrogen generation at temperatures of 283K-303K. Our product showed an improved activation energy of 51 kJ mol-1 when compared to previous carbon allotrope supported catalysts.3,5 This work can be used to create new catalyst composites to for the generation of hydrogen energy as an alternative fuel source.Works Cited: Masa, J.; Weide, P.; Peeters, D.; Sinev, I.; Xia, W.; Sun, Z.; Somsen, C.; Muhler, M.; Schuhmann, W. Amorphous Cobalt Boride (Co2B) as a Highly Efficient Nonprecious Catalyst for Electrochemical Water Splitting: Oxygen and Hydrogen Evolution. Advanced Energy Materials 2016, 6 (12).Schlesingehr H.I.; Brown, H.C.; Finholt A.E.; Gilbreath J.R.; Hoekstra H.R.; Hyde E.L.; Sodium Borohydride, Its Hydolysis and its Use as a Reducing Agent in the Generation of Hydrogen; Chem. Soc., (1953), 75 (1), pp 215–219Clay Huff, Julia M. Long, Austin Heyman, and Tarek M. Abdel-Fattah Palladium Nanoparticle Multiwalled Carbon Nanotube Composite as Catalyst for Hydrogen Production by the Hydrolysis of Sodium BorohydrideACS Applied Energy Materials 2018 1 (9), 4635-4640 DOI: 10.1021/acsaem.8b00748Huff, C., Dushatinski, T., & Abdel-Fattah, T. M.. Gold nanoparticle/multi-walled carbon nanotube composite as novel catalyst for hydrogen evolution reactions. International Journal of Hydrogen Energy (2017) 42(30), 18985 18990.doi:10.1016/j.ijhydene.2017.05.226Semasko, M., Tamasauskaite-Tamasiunaite, L., Stalnioniene, I., Zieliene, A., Vaiciuniene, J., Simkunaite-Stanyniene, B., ... Norkus, E.. Hydrogen Generation via Sodium Borohydride Hydrolysis Using the Graphene Supported Platinum-Ruthenium-Cobalt Catalysts Prepared nu Microwave-Assisted Synthesis. ECS Transactions, (2015) 68(3), 37–44.doi:10.1149/06803.0037ecst Figure 1: SEM image of clusters of particles formed from graphene like sheets. These clusters range in size but are generally seen 25 microns or less Figure 1

A Novel Synthesis of Manganese Borides Supported on Multi-Walled Carbon Nanotubes As a Catalyst for the Hydrolysis of Sodium Borohydride

The current world energy crisis is concerned with the depletion of natural resources usedby power industries. Hydrogen energy produced from feedstock materials such as sodium borohydride (NaBH4) arises as a potential solution for energy demand, but it meets a challenge in finding a durable, efficient and economical catalyst.1,2 A catalyst is required to produce a usable amount of hydrogen through the hydrolysis reaction of NaBH4, due to the limitation that the procedure does not occur quickly enough on its own.2 Metal borides have been researched and applied in various industries as an effective catalyst, but the method of production appears to be costly and eco-unfriendly.3,4 In this study, manganese metal organic frame works (Mn-MOFs) and multi-walled carbon nanotubes (MWCNTs) were applied to synthesize supported manganese borides at room temperature in aqueous conditions. The MOFs have been applied in solving environmental pollution issues and enhance the catalytic effect.5 When combined with MWCNT, it further improves the stability, surface area, and reusability of the manganese borides. The reduction of Mn-MOFs leads to the formation of manganese borides on MWCNTs in the presence of NaBH4, which acts as both a reduction agent and a hydrogen feedstock material in this experiment. The physicochemical structures of the obtained composite, MnB@MWCNT was characterized via x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and inductively coupled plasma (ICP). The catalytic capability of MnB@MWCNT was tested in an aqueous solution of NaBH4 under various conditions. The catalytic ability and reusability of MnB@MWCNT was measured by a water displacement method while the activation energy was found using a plot of the Arrhenius equation which utilized various temperature trials of 283 K, 295 K and 303 K.6 Five consecutive reusability trials were performed separately in which the production of hydrogen fell from 62.12 mL to 18.44 mL by the final trial and the activation energy was ultimately calculated to be 119.86 kJ mol-1. The results of this synthesis support the idea that supported manganese borides supported over multi-walled carbon nanotubes can act as an efficient catalyst in hydrogen evolution reactions, in the presence of hydrogen feedstock materials.

Novel Synthesis of Graphene Supported Nickel Borides from Metal Organic Framework Precursors

As the worlds supply of fossil fuels dwindles, more and more research is being conducted to find a reliable alternative energy source. One promising source of energy is hydrogen, which is not only the most abundant element in the universe, but when burned as a fuel source produces only water as a biproduct. The main issue preventing hydrogen from being utilized as a fuel source is the storage. Hydrogen primarily exists as a gas and must be stored in compressed tanks. These tanks run the risk of explosions, so work is being done to produce hydrogen gas over time with a hydrogen feedstock material (HFM). Sodium borohydride (NaBH4) is an HFM that contains 10.8% hydrogen by weight and readily reacts with water to produce hydrogen gas.1 This reaction occurs slowly and needs a catalyst to make its hydrogen production viable. In the past, work has been done with precious metal catalysts and metal catalyst support on carbon materials.2,3 The goal of this study was to explore a novel method of synthesizing nickel borides supported on graphene (NiB@G). NiB@G was formed by the reduction of a metal organic framework precursor (NiMOF-5@GO) at room temperature (RT 295K). Both NiMOF-5@GO and NiB@G were characterized using Powder X-Ray Diffraction (PXRD), Scanning Electron Mircroscopy (SEM, Figure 1), Energy Dispersive X-Ray Spectroscopy (EDS), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). NiB@G was additionally characterized with Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and tested for its catalytic ability at temperatures of 283K-303K. This product showed an excellent activation energy of 49 kJ mol-1 compared to previous work with nickel, cobalt, and raney-nickel catalysts.4 This product also showed good stability, performing well after multiple uses of the same catalyst. A novel method of producing an efficient catalyst for the hydrolysis of sodium borohydride will help scientists move forward in the mass production of hydrogen fuel.Works Cited: Schlesingehr H.I.; Brown, H.C.; Finholt A.E.; Gilbreath J.R.; Hoekstra H.R.; Hyde E.L.; Sodium Borohydride, Its Hydolysis and its Use as a Reducing Agent in the Generation of Hydrogen; Chem. Soc., (1953), 75 (1), pp 215–219Clay Huff, Julia M. Long, Austin Heyman, and Tarek M. Abdel-Fattah Palladium Nanoparticle Multiwalled Carbon Nanotube Composite as Catalyst for Hydrogen Production by the Hydrolysis of Sodium BorohydrideACS Applied Energy Materials 2018 1 (9), 4635-4640 DOI: 10.1021/acsaem.8b00748Huff, C., Long, J. M., Aboulatta, A., Heyman, A., & Abdel-Fattah, T. M. Silver Nanoparticle/Multi-Walled Carbon Nanotube Composite as Catalyst for Hydrogen Production. ECS Journal of Solid State Science and Technology (2017) 6(10), M115–M118. doi:10.1149/2.0051710jssKaufman, C. M., & Sen, B. (). Hydrogen generation by hydrolysis of sodium tetrahydroborate: effects of acids and transition metals and their salts. Journal of the Chemical Society, Dalton Transactions, 1985 (2), 307. doi:10.1039/dt9850000307 Figure 1: SEM images at 50 microns of the graphene support for the nickel borides. The clear presence of graphene like sheets is seen in the image with conglomerates of sheets have dimensions of much larger than 50 microns Figure 1

The coralline cobalt oxides compound of multiple valence states deriving from flower-like layered double hydroxide for efficient hydrogen generation from hydrolysis of NaBH4

Efficient hydrogen storage, transportation and generation are key-technology for future hydrogen economy. Sodium borohydride (NaBH4) stands out as promising hydrogen energy carrier with merits of high volumetric density and environmentally benign hydrolysis products. Flower-like layered double hydroxide α-Co(OH)2 with intercalation of B species was synthesized via hydrothermal crystallization method using sodium tetraphenylboron as source of B and alkaline, which makes it different from the previous supporting materials. Pure or mixed cobalt oxides with different valence states containing B (CoO/B, Co3O4/B, Co+CoO/B, CoO+Co3O4/B) were subtly prepared via controlling calcination temperature, time and atmosphere for sodium borohydride hydrolysis. Coral-like CoO+Co3O4/B displayed superior hydrogen generation rate (6478 mlH2·min−1·g−1metal) with arrhenius activation energies of 41.14 kJ/mol for NaBH4 hydrolysis in alkaline solutions compared to those reported pure precious metals. The out-standing catalytic performance of CoO+Co3O4/B may be attributed to electron transfer among cobalt oxide. DFT calculation indicates NaBH4 hydrolysis undergoes a reaction path on CoO+Co3O4 surface with lower relative energies.

Metal-Organic Framework (MOF)-Derived Electron-Transfer Enhanced Homogeneous PdO-Rich Co3 O4 as a Highly Efficient Bifunctional Catalyst for Sodium Borohydride Hydrolysis and 4-Nitrophenol Reduction.

Developing a bifunctional catalyst with low cost and high catalytic performance in NaBH4 hydrolysis for H2 generation and selective reduction of nitroaromatics will make a significant impact in the field of sustainable energy and water purification. Herein, a low-loading homogeneously dispersed Pd oxide-rich Co3 O4 polyhedral catalyst (PdO-Co3 O4 ) with concave structure is reported by using a metal-organic framework (MOF)-templated synthesis method. The results show that the PdO-Co3 O4 catalyst has an exceptional turnover frequency (3325.6 molH2 min-1 molPd -1 ), low activation energy (43.2 kJ mol-1 ), and reasonable reusability in catalytic H2 generation from NaBH4 hydrolysis. Moreover, the optimized catalyst also shows excellent catalytic performance in the NaBH4 selective reduction of 4-nitrophenol to 4-aminiphenol with a high first-order reaction rate of approximately 1.31 min-1 . These excellent catalytic properties are mainly ascribed to the porous concave structure, monodispersed Pd oxide, as well as the unique synergy between PdO and Co3 O4 species, which result in a large specific surface area, high conductivity, and fast solute transport and gas emissions.

Bacterial cellulose derived carbon as a support for catalytically active Co–B alloy for hydrolysis of sodium borohydride

The fast release of hydrogen from borohydride is highly desired for a fuel cell system. However, the generation of hydrogen from borohydride is limited by the low activity and low stability of the catalyst. Herein, a highly active catalyst is synthesized through a simple one-step chemical reduction using bacterial cellulose (BC) derived carbon as a support for the active Co–B alloy. The morphology and microstructure of the BC/Co–B nanocomposite are characterized by SEM, TEM, XRD, and BET adsorption analysis. The BC/Co–B possesses high surface area (125.31 m2 g−1) high stability and excellent catalytic activity for the hydrolysis of NaBH4. Compared with unsupported Co–B nanocomposite or commercial carbon supported Co–B, the BC/Co–B nanocomposite shows greatly improved catalytic activity for the hydrolysis of NaBH4 with a high hydrogen generation rate of 3887.1 mL min−1 g−1 at 30 °C. An activation energy of 56.37 kJ mol−1 was achieved for the hydrolysis reaction. Furthermore, the BC/Co–B demonstrated excellent stability. These results indicate that the BC/Co–B nanocomposite is a promising candidate for the hydrolysis of borohydrides.

As a highly efficient reduced graphene oxide-supported ternary catalysts for the fast hydrogen release from NaBH4

In this study, reduced graphene oxide (rGO)-based Co–Cu–B nanocatalysts were produced to catalytic efficiency of hydrogen (H2) generation from sodium borohydride (NaBH4) hydrolysis reaction. The characterization was achieved by X-ray diffraction, field emission scanning electron microscope (S-4800) and energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectroscopy. Co–Cu–B(5%(wt))/rGO trimetallic nanoparticles provide an initial H2 production rate of 13,000 mL g−1 min−1 (3%(wt) NaBH4), turnover frequency 4013 h−1 and activation energy (Ea) 36.76 kJ mol−1 at room temperature that shows higher catalytic activity than most of the recently reported noble metal based on a heterogeneous catalyst that is used in the reaction of hydrolytic dehydrogenation of NaBH4. The excellent hydrolysis performance of Co–Cu–B(5%(wt))/rGO can be attributed to both synergistic effect and high surface area of rGO. The improvement of effective and inexpensive Co–Cu–B(5%(wt))/rGO catalysts enhances the applicability of NaBH4 as chemical H2 safekeeping equipment that can be used in the H2 fuel cell industry.

Highly active and stable CeO2 supported nickel-complex catalyst in hydrogen generation

Cerium oxide supported 5-Amino-2,4-dichlorophenol-3,5-ditertbutylsalisylaldimine-Nickel complex for the first time was used to produce H2 from hydrolysis of sodium borohydride. Cerium oxide supported Nickel complex catalyzed hydrolysis system was studied depend on temperature, concentration of sodium hydroxide, amount of Cerium oxide supported Ni complex catalyst, concentration of Ni complex and concentration of sodium borohydride. Cerium oxide supported Ni(II) complex display highly effective catalytic activity in sodium borohydride hydrolysis reaction. The obtained Cerium oxide supported Ni(II) complex catalyst was characterized by using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscope, Transmission Electron Microscope, Brunauer-Emmett-Teller Surface Area Analysis, X-Ray Diffraction Analysis techniques. The catalyst stability was tested, even the fifth recycle the catalytic activity was maintained at 100%. Additionally the proposed Cerium oxide supported-Ni (II) complex catalyzed sodium borohydride hydrolysis mechanism was determined carefully. The experimental results showed that Cerium oxide supported Ni (II) complex catalyst accelerate sodium borohydride hydrolysis with 43,392 and 19,630 mL H2 gcat−1 min−1 hydrogen production rates at 50 °C and 30 °C respectively and 20,587 kJ mol−1 activation energy.

Hydrogen Generation upon Nanocatalyzed Hydrolysis of Hydrogen-Rich Boron Derivatives: Recent Developments.

ConspectusProduction of hydrogen from nonfossil sources is essential toward the generation of sustainable energy. Hydrogen generation upon hydrolysis of stable hydrogen-rich materials has long been proposed as a possibility of hydrogen disposal on site, because transport of explosive hydrogen gas is dangerous. Hydrolysis of some boron derivatives could rapidly produce large amounts of hydrogen, but this requires the presence of very active catalysts. Indeed, late transition-metal nanocatalysts have recently been developed for the hydrolysis of a few hydrogen-rich precursors.Our research group has focused on the improvement and optimization of highly performing Earth-abundant transition-metal-based nanocatalysts, optimization of remarkable synergies between different metals in nanoalloys, supports including positive synergy with nanoparticles (NPs) for rapid hydrogen generation, comparison between various endo- or exoreceptors working as homogeneous and heterogeneous supports, mechanistic research, and comparison of the nanocatalyzed hydrolysis of several boron hydrides.First, hydrogen production upon hydrolysis of ammonia borane, AB (3 mol H2 per mol AB) was examined with heterogeneous endoreceptors. Thus, a highly performing Ni@ZIF-8 nanocatalyst was found to be superior over other Earth-abundant nanocatalysts and supports. With 85.7 molH2·molcat-1·min-1 at 25 °C, this Ni nanocatalyst surpassed the results of previous Earth-abundant nanocatalysts. The presence of NaOH accelerated the reaction, and a remarkable pH-dependent "on-off" control of the H2 production was established. Bimetallic nanoalloys Ni-Pt@ZIF-8 showed a dramatic volcano effect optimized with a nanoalloy containing 2/3 Ni and 1/3 Pt. The rate reached 600 molH2·molcat-1·min-1 and 2222 molH2·molPt-1·min-1 at 20 °C, which much overtook the performances of both related nanocatalysts Ni@ZIF-8 and Pt@ZIF-8. Next, hydrogen production was also researched via hydrolysis of sodium borohydride (4 mol H2 per mol NaBH4) using nanocatalysts in ZIF-8, and, among Earth-abundant nanocatalysts, Co@ZIF-8 showed the best performance, outperforming previous Co nanocatalysts. For exoreceptors, "click" dendrimers containing triazole ligands on their tripodal tethers were used as supports for homogeneous (semiheterogeneous) catalysis of both AB and NaBH4 hydrolysis. For both reactions, Co was found to be the best Earth-abundant metal, Pt the best noble metal, and Co1Pt1 the best nanoalloy, with synergistic effects. Based on kinetic measurements and kinetic isotope effects for all of these reactions, mechanisms are proposed and the hydrogen produced was further used in tandem reactions. Overall, dramatic triple synergies between these nanocatalyst components have allowed hydrogen release within a few seconds under ambient conditions. These nanocatalyst improvements and mechanistic findings should also inspire further nanocatalyst design in various areas of hydrogen production.