Hydrogen Generation Rate Research Articles

The evaluation of hydrogen production via a geothermal-based multigeneration system with 3E analysis and multi-objective optimization

In this study, a novel geothermal-based multigeneration system is designed and evaluated in energy, exergy and economic (3E) analyses. Besides 3E analyses, multi-objective optimization has been assessed to reach the highest exergetic effectiveness and the lowest total cost rate. To evaluate the designed plant, thermodynamic balance equations are assigned to all sub-systems found in the design. These equations are solved by using Engineering Equation Solver (EES) software. According to the analyses' results, with base parameters, total power production is 1951 kW, the hydrogen generation rate is 0.0015 kg/s, and the whole energy and exergy efficiencies are 59.53% and 53.17%. The economic analysis performed for the multigeneration system indicates that the total cost rate is 186 $/h, and the levelized energy cost is 0.102 $/kWh. These results indicate that the designed geothermal-based multigeneration system performs better than a single-generation plant in terms of efficiency and cost.

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.

Study on the integrity of prolonged steam oxidized clad column quenched at various reflood rates

An unmitigated loss of coolant flow accident degrades the decay heat removal from the reactor core. Because of this situation, the temperature of the clad column escalates. The steam surrounding the cladding causes an exothermic oxidation reaction between the cladding surface and steam at elevated temperatures typically above 700 °C. Under such a scenario, the fire fighting water injects into the core to reduce the accident severity and arrest the clad temperature escalation. Usually, violent heat exchanges happen between the clad column and cold water during the late reflood quenching event. Furthermore, the expansion and subsequent shrinkage of the clad column could be structurally constrained. Thus, the oxidized clad column may be exposed to unchecked thermal shock during the reflood quenching of a severely heated core, causing clad failure or fracture.In this study, a 2x2 square lattice arrangement of the zircaloy-4 cluster is selected for the experiment. This is to study the quenching behaviour of the cluster prolonged heated (1150⁰ C- 1250⁰C) clad column in steam media, simulating late phase injection of DEC-A scenario. The bottom reflooding is carried out at flow rates between 3 and 10 L per minute, typical to a light water reactor SAMG action. This study explores the qualitative structural integrity of the clad column. The analytical hydrogen generation is also estimated for all cases using the Baker and Just correlation. The experimentally measured transient hydrogen generation rate agrees well with the analytical prediction. The maximum amount of equivalent cladding reacted is 27 % during heating. A renewed enhanced oxidation leads to a drastic shoot-up in the hydrogen concentration during the reflood quenching. Nevertheless, the maximum hydrogen shoot-up remains the same irrespective of the reflood rates. The clad column in each test case has failed during reflooding.

Modification of Electrospun CeO2 Nanofibers with CuCrO2 Particles Applied to Hydrogen Harvest from Steam Reforming of Methanol.

Hydrogen is the alternative renewable energy source for addressing the energy crisis, global warming, and climate change. Hydrogen is mostly obtained in the industrial process by steam reforming of natural gas. In the present work, CuCrO2 particles were attached to the surfaces of electrospun CeO2 nanofibers to form CeO2-CuCrO2 nanofibers. However, the CuCrO2 particles did not readily adhere to the surfaces of the CeO2 nanofibers, so a trace amount of SiO2 was added to the surfaces to make them hydrophilic. After the SiO2 modification, the CeO2 nanofibers were immersed in Cu-Cr-O precursor and annealed in a vacuum atmosphere to form CeO2-CuCrO2 nanofibers. The CuCrO2, CeO2, and CeO2-CuCrO2 nanofibers were examined by X-ray diffraction analysis, transmission electron microscopy, field emission scanning electron microscopy, scanning transmission electron microscope, thermogravimetric analysis, and Brunauer-Emmett-Teller studies (BET). The BET surface area of the CeO2-CuCrO2 nanofibers was 15.06 m2/g. The CeO2-CuCrO2 nanofibers exhibited hydrogen generation rates of up to 1335.16 mL min-1 g-cat-1 at 773 K. Furthermore, the CeO2-CuCrO2 nanofibers produced more hydrogen at lower temperatures. The hydrogen generation performance of these CeO2-CuCrO2 nanofibers could be of great importance in industry and have an economic impact.

Facilitated charge transfer in ZnIn2S4@CuInP2S6 heterojunctions towards efficient photocatalytic H2 generation

Accelerating charge separation and migration in semiconductor photocatalysts is the key for acquiring high performance in the photocatalytic hydrogen generation reaction. In this work, a new ZnIn2S4/CuInP2S6 hetero-structured system (ZIS/CIPS) is designed and constructed. Owing to the presence of face-to-face hetero-interface with high charge-transport capability, the photocatalytic hydrogen generation rate of ZIS/CIPS dramatically enhanced (76.2 μmol h−1) under the visible-light irradiation, which is up to 13 and 190 times compared to that of ZnIn2S4 and CuInP2S6 (CIPS), respectively.

Photocatalytic overall water splitting hydrogen production over ZnCdS by spatially-separated WP and Co3O4 cocatalysts

Loading suitable oxidation and reduction cocatalysts on sulfide semiconductor photocatalysts for H 2 and O 2 production reaction still remain a great challenge. Herein, we present a simple physical mixing strategy to load reduction cocatalyst WP and oxidation cocatalyst Co 3 O 4 co-modification ZnCdS (WP–Co/ZCS) with excellent photocatalytic water splitting activity. The co-modification of the double auxiliary catalysts can efficiently accelerate the separation of photocarriers, enhance the reaction kinetics and significantly advance the photocatalytic activity. The maximum hydrogen evolution rate of 21.44 mmol g -1 h -1 is attained over 10% WP-Co/ZCS photocatalyst, which is about 6.5 folds higher than bare ZnCdS, and a high photostability is also obtained. Meanwhile, a notable quantum efficiency of 27.6% at 420 nm and solar-hydrogen conversion efficiency (STH) of 1.57% are achieved, which is significantly surpassing many reported ZnCdS-based photocatalysts. Remarkably, an efficient and stable photocatalytic overall water splitting activity are achieved with hydrogen and oxygen generation rates of 61 μmol g -1 h -1 and 32.5 μmol g -1 h -1 for 10% WP-Co/ZCS, respectively. This work provides a new idea for designing oxidation and reduction dual-catalysts on ZnCdS nanoparticles to advance photocatalytic hydrogen generation performance and achieve pure water splitting. An efficient WP/Co 3 O 4 /ZnCdS dual cocatalysts photocatalytic system was constructed for overall water splitting. The highest photocatalytic H 2 production rate of 21.44 mmol g -1 h -1 is achieved over 10% WP-Co/ZnCdS with a high AQE of 27.6% at 420 nm. And the solar-hydrogen conversion efficiency (STH) is up to 1.57% for 10% WP-Co/ZnCdS. Remarkably, an efficient and stable photocatalytic overall water splitting activity are achieved with hydrogen and oxygen generation rates of 61 μmol g -1 h -1 and 32.5 μmol g -1 h -1 for 10% WP-Co/ZCS, respectively. • An efficient WP/Co 3 O 4 /ZnCdS dual cocatalysts photocatalytic system was constructed. • Photocatalytic H 2 production rate of 21.44 mmol g -1 h -1 is achieved over 10% WP-Co/ZnCdS with a high AQE of 27.6% at 420 nm. • The solar-hydrogen conversion efficiency (STH) is 1.57% for 10% WP-Co/ZnCdS. • Matching of HER/OER via WP and Co 3 O 4 can actualize the overall water splitting. • Photocatalytic overall water splitting for H 2 /O 2 generation rates are 61/32.5 μmol g -1 h -1 over 10% WP-Co/ZCS.

Heterointerface Engineering of ZnO/CdS Heterostructures through ZnS Layers for Photocatalytic Water Splitting.

Solar-driven water splitting to produce clean and renewable hydrogen offers a green strategy to address the energy crisis and environmental pollution. Heterostructure catalysts are receiving increasing attention for photocatalytic hydrogen generation. ZnO/ZnS/CdS and ZnO/CdS heterostructures have been successfully designed and prepared according to two different strategies. By introducing a heterointerface layer of ZnS between ZnO and CdS, a Z scheme charge-transfer channel was promoted and achieved superior photocatalytic performance. A highest hydrogen generation rate of 156.7 μmol g-1 h-1 was achieved by precise control of the thickness of the heterointerface layer and of the CdS shell. These findings demonstrated that heterostructures are promising catalysts for solar-driven water splitting, and that heterointerface engineering is an effective way to improve the photocatalytic properties of heterostructures.

Simulation of high temperature fuel rod bundle behavior during the QUENCH-06 experiment using CINEMA code

The CINEMA code has been developed to secure the ability to analyze severe accidents in nuclear power plants with a Korean domestic computer code. As part of the code validation, the current work simulated the QUENCH-06 experiment with the CINEMA. Calculation results from CINEMA were compared to the experimental results and numerical results of SPACE and SCDAP/RELAP5. CINEMA overestimated the bundle temperatures near the test section entrance, as observed in the SPACE and SCDAP/RELAP5 calculation due to an underestimation of the thermal conductivity of argon-filled ZrO2 fiber insulation. The hydrogen generation rate was overestimated by the CINEMA because of the high bundle temperature at the upper part, where CINEMA is unable to model extreme heat loss through the shroud without insulation. The CINEMA results demonstrated good agreement with the experimental data, validating that the CINEMA is capable of simulating high temperature fuel rod behavior before and during the reflood phase.

Improved Hydrogen Generation of Al-H2O Reaction by BiOX (X = Halogen) and Influence Rule.

In this work, three additives BiOX (BiOI, BiOBr, and BiOF) for Al-H2O reaction have been synthesized using chemical methods. SEM analysis shows that the structure of BiOF is nanoparticles, while BiOBr and BiOI have flower-like structures composed of nanosheets. Then, Al-BiOI, Al-BiOBr, and Al-BiOF composites have been prepared using the ball milling method. The effect of halogen ions on the performance of hydrogen generation from Al hydrolysis has been explored. The results indicate that the conversion yields of Al-BiOBr, Al-BiOI, and Al-BiOF for hydrogen generation are 96.3%, 95.3%, and 8.9%, respectively. In particular, the maximum hydrogen generation rate (MHGR) of Al-BiOI is as high as 3451.8 mL g-1 min-1, eight times higher than that of Al-BiOBr. Furthermore, the influence rule of BiOX (X = F, Cl, Br, and I) on Al-H2O reaction has been studied using density functional theory. The results illustrate that HI can be more easily adsorbed on the Al surface as compared with HF, HCl, and HBr. Meanwhile, the bond length between halogen ions and the Al atom increased in the order of F-, Cl-, Br-, and I-. Therefore, the dissociation of I- from the Al surface becomes easier and will expose more active sites to enhance the reaction activity of Al. In summary, the BiOI has the most favorable performance to Al-H2O reaction.

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.

Boosting charge separation of CeO2–MnO2 nanoflake with heterojunctions for enhanced photocatalytic hydrogen generation

Herein, we report about the synthesis and tuning of a highly conductive CeO2–MnO2 composite with cubic fluorite CeO2 and tetragonal MnO2 for industrial photocatalytic hydrogen generation. Specific nanoflake morphology and enhanced electron transfer during photo-excitation of the composite are tailored by fine tuning of the composition and synthesis parameters. The tuned composite (1:1 CeO2–MnO2) with heterojunctions results in the enhanced photoresponse characteristics due to low band gap energy (2.4 eV), low electron-hole recombination rate, increased electron lifetime (7.92 ns) and efficient electron transfer ability. The composite exhibits enhanced rate of photocatalytic hydrogen generation (540 μmol h−1) under visible light irradiation during long term analysis with excellent stability and reusability, competent to commercial grade photocatalysts.

Silicon nanoparticles for oral administration of molecular hydrogen

Medical use of hydrogen gas (H2) has been given increasing attention over the past 15 years with numerous clinical trials for a variety of indications. The biological activity of H2 includes antioxidant properties and thereby the ability to neutralize damaging reactive oxygen species (ROS). Administration of hydrogen as a medical gas is limited by the poor water solubility and by the flammability of H2 in air. Therefore, nanocarriers have been investigated for safer and more efficient administration of hydrogen. Silicon particles are suggested for oral administration with the ability to undergo a redox reaction with water to produce H2in vivo. The purpose of this work was to investigate the hydrogen generating abilities of silicon particles synthesized by centrifugal chemical vapor deposition (cCVD). High hydrogen generation rates up to 1310 ml/g at physiological pH 7.4 (82 % yield) were observed. An in vitro model of oral administration showed that pretreatment in artificial gastric juice did not affect hydrogen generation. Thus, the cCVD silicon particles seem to be suitable for in vivo hydrogen generation. A surface carbon coating or addition of surfactants or albumin hindered hydrogen generation. The addition of egg white reduced hydrogen generation but did not block it.

N-doped carbon layer promoted charge separation/transfer in WP/g-C3N4 heterostructures for efficient H2 evolution and 4-nitrophenol removal

Monodispersed WP nanoparticles were encapsulated in nitrogen-doped carbon (NC) layers via thermal polymerization at high temperature. The intimate interface between WP and NC accelerated charge transfer and elevated the electroconductivity. As-prepared WP@NC nanocomposites revealed enhanced electrocatalytic hydrogen evolution reaction (HER) activities in both of acidic and alkaline electrolytes with Tafel slopes of 73 and 85 mv/dec, respectively. Furthermore, WP@NC nanocomposites instead of noble metal co-catalysts were loaded on superior thin g-C3N4 nanosheets (CN) by thermal polymerization at different temperature. In the case of without Pt, the photocatalytic hydrogen generation rate of CN/WP@NC heterojunctions prepared using optimized conditions reached 1217.6 μmol g−1 h−1, which was ∼196 folds of pure g-C3N4 nanosheets. This is ascribed to that N-doped carbon layers on WP improved the separation and transfer efficiency of photogenerated charge carriers. Interestingly, the carbon layers improved the chemical stability and corrosion resistance to ensure enhanced photocatalytic hydrogen generation in simulated seawater. In addition, the sample revealed outstanding light-assisted elimination capability of 4-nitrophenol (4-NP) because of the selective hydrogenation reaction to 4-aminophenol and photodegradation reaction of 4-NP. Under visible light irradiation, the removal efficiency using CN/WP@NC reached 99% within 10 min. The kinetic constant (0.443 min−1) was 17.8 times of that of g-C3N4 nanosheets. This work supplied an efficient method to fabricate bi-functional noble-metal-free catalyst towards clean energy production and environment remediation.

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 .

Efficient photocatalytic H2 production and ofloxacin degradation based on heterodimensional Z-scheme P-C3N4/MIL-88A(Fe) heterojunctions

The production of effective photocatalyst to generate H2 and eliminate pollutants is still a challenge. A simple solvothermal approach is demonstrated for synthesizing a coupled P-C3N4/MIL-88A(Fe) composite wherein two-dimensional phosphorus-doped g-C3N4 nanosheets are attached to three-dimensional MIL-88A. The P-CN/MIL-88A composite shows superior photocatalytic ability with a high hydrogen generation rate of 34.53 mmol/(g·h) and an ofloxacin degradation rate of 95.6%. The H2 evolution rate of the composite is approximately 38.3 times that of bulk g-C3N4 (B-CN). The enhancement mechanisms resulting in high efficiency and adaptability are attributed to the Z-scheme (2D/3D) P-CN/MIL-88A heterojunction, which has unique synergistic interface properties, good photoinduced electron mobility, and good electron-hole pair separation ability. This work provides insights into the design of 2D/3D heterostructure photocatalysts for highly efficient and simultaneous photocatalytic H2 production and antibiotic degradation.

A novel nanoporous Mg-Li material for efficient hydrogen generation

• Nanoporous Mg-Li material is successfully prepared for the first time. • This material can deliver 962 ml g −1 H 2 in 15 min at 0 °C and in 3 min at 50 °C. • The advances come from the nanoporous structure and the addition of li element. • The growth mechanism of the nanoporous Mg-Li material is proposed. Hydrogen generation material is a new kind of energy material that can supply hydrogen by reacting with water and is drawing more and more attention with the development of hydrogen economy. In this study, a novel nanoporous magnesium-lithium material prepared by a physical vapor deposition method exhibits an excellent hydrogen generation property. It generates hydrogen efficiently and quickly with saltwater, reaching a hydrogen generation amount of 962 mL g −1 and hydrogen generation rates of 60 mL g −1 min −1 , 109 mL g −1 min −1 , 256 mL g −1 min −1 and 367 mL g −1 min −1 at 0 °C, 25 °C, 35 °C and 50 °C, respectively. The nanoporous magnesium-lithium material is composed of a solid solution phase with a magnesium-lithium atomic ratio of 17:3. By synchrotron radiation analysis, the sizes of the nanopores are in the range of 100 nm ∼ 600 nm with an average size of 280 nm, and the porosity is calculated to be ∼42.4%. The improved hydrogen generation property is attributed to the nanoporous structure with a high specific surface area, and the addition of lithium element which acts as active sites in hydrogen generation process.

Electronic transfer enhanced coral-like CoxP loaded Ru nanoclusters as efficient catalyst for hydrogen generation via NaBH4 hydrolysis

The slow kinetics of NaBH4 hydrolysis to generate hydrogen can be effectively improved by designing the composite catalysts of precious metals and transition metals, while their micro-combined structure still needs to be improved. Herein, the coral-like CoxP with high specific surface area is fabricated by ZIF-67 in-situ etching, annealing, phosphating and loading in turns, 1.5 nm Ru nanocluster species are uniformly loaded on the skeleton surface of CoxP, and there is the strong electronic effect between Ru and CoxP. By further adjusting the loading of Ru, the optimized Ru3.4@CoxP catalyst has lower activation energy (32.8 kJ mol−1) than CoxP, and displays higher turnover frequency (606molH2min−1molRu−1) and hydrogen generation rate (4551mLmin−1gcatalyst−1) than the comparative and most reported similar catalysts during NaBH4 hydrolysis. Furthermore, After five cycles, the catalytic activity of Ru3.4@CoxP is only reduced by 25.6%. The excellent catalytic activity is due to the micro-nano structure with high specific surface area and the synergistic effect between Ru and Co species providing more catalytic active sites, which is the precise and controllable design method for developing noble metal/transition metal composite catalyst.

ZIF-67 and Cobalt-based@heteroatom–doped carbon nanomaterials for hydrogen production and dyes removal via adsorption and catalytic degradation

Metal-organic frameworks (MOFs) are promising catalysts for producing clean energy and environmental-based applications. This paper reported one-pot encapsulation of guest molecules, e.g., thiourea (TU) and D-Glucose-6-phosphate disodium salt dihydrate (G6P-Na2), into zeolitic imidazolate frameworks (ZIF-67), denoted as S@ZIF-67 and P@ZIF-67, respectively. The organic guest molecules offered the synthesis of cobalt-based materials (e.g., Co3O4, CoP, and CoS), embedded heteroatoms (P, N, and S) via carbonization. The materials were tested for hydrogen generation via sodium borohydride (NaBH4) hydrolysis. ZIF-67, S@ZIF-67, and P@ZIF-67 displayed maximum hydrogen generation rates (HGRmax) of 27,273, 24,000, and 60,000 mLH2 gcat−1 min−1, respectively, using 20 mg of the catalyst and 0.2 wt.% of NaBH4 at 60 °C. The materials were also investigated as potential catalysts for the adsorption and catalytic degradation of water pollutants such as organic dyes, e.g., methyl orange (MO) and Congo red (CR), with degradation efficiency of 100% and 99% in a short time (30–60 min).

In situ evolved defective TiO2 as robust support for CoB-catalyzed hydrolysis of NaBH4

Sodium borohydride (NaBH4) has been proposed to be a realizable hydrogen supplier for proton-exchange membrane fuel cell. Cobalt boride (CoB) is one of the most promising non-precious metal-based catalysts toward NaBH4 hydrolysis. In this work, we develop a facile method to synthesize defects-rich TiO2 supported CoB nanoparticles (CoB/TiO2-x). In this CoB/TiO2-x, an electronic metal-support interaction is induced by transferring electrons from the defective TiO2 to CoB to form electron-rich CoB particles, facilitating the hydrolysis of NaBH4. The as-synthesized CoB/TiO2-x catalyst shows a good catalytic performance with hydrogen generation rate of 3070 mL min−1 gCo−1 and activation energy of 57.03 kJ mol−1.

Catalytic hydrolysis of sodium borohydride for hydrogen production using phosphorylated silica particles.

Hydrolysis of sodium borohydride (NaBH4) offers substantial applications in the production of hydrogen but requires an inexpensive catalyst. Herein, silica (SP) and phosphorylated silica (SP-PA) are used as a catalyst for the generation of hydrogen from NaBH4 hydrolysis. The catalyst is prepared by sol-gel route synthesis by taking tetraethyl orthosilicate as the precursor of silica whereas phosphoric acid served as the gelation and phosphorylating agent. The prepared catalyst is characterized by FT-IR spectroscopy, XRD, SEM, and EDAX. The hydrogen generation rate at SP-PA particles (762.4mLmin-1g-1) is higher than that of silica particles (133mLmin-1g-1 of catalyst). The higher catalytic activity of SP-PA particles might be due to the acidic functionalities that enhance the hydrogen production rate. The kinetic parameters(activation energy and pre-exponential factor) are calculated from the Arrhenius plot and the thermodynamic parameters (enthalpy, entropy, and free energy change) are evaluated using the Erying plot. The calculated activation energy for NaBH4hydrolysis at SP-PA catalyst is 29.92kJ.mol-1 suggesting the high catalytic activity of SP-PA particles. The obtained entropy of activation (ΔS‡ = - 97.75 JK-1) suggested the Langmuir-Hinshelwood type associative mechanism for the hydrolysis of NaBH4at SP-PA particles.