Free Hydrogen Production Research Articles

Perspectives on CO2-Free Hydrogen Production: Insights and Strategic Approaches

Perspectives on CO₂-Free Hydrogen Production: Insights and Strategic Approaches

Solar-driven Pt free hydrogen production and successive degradation of sulfasalazine using CuO/ZnO binary nanocomposites: Reaction kinetics and determination of reaction parameters using response surface methodology

BackgroundApproaches for sustainable, green, and expensive catalyst-free hydrogen production have not been explored extensively. Moreover, during photocatalysis, a lot of material gets wasted due to a lack of proper optimization of the reaction parameters to remove the toxic industrial effluents. MethodsHere in this study, we present the green synthesis of CuO/ZnO nanocomposites from the ethanolic crude extract of Oxystelma esculentum. The synthesized photocomposites were systematically characterized by Fourier transform infrared spectroscopy, zeta potential, x-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. The performed analyses provided useful insights into identifying important functional groups, size, morphology, elemental composition, crystallinity, and defects in the synthesized photocomposites. Significant FindingsAfter characterization, the nanocomposites were evaluated for photocatalytic sulfasalazine (SSZ) degradation and hydrogen production. The response surface methodology (RSM) was employed to optimize SSZ's photocatalytic degradation. The optimized values of reaction parameters for the photocatalytic degradation of SSZ comprise pH = 4.06, SSZ dose = 47.75 mg/L, CuO/ZnO dose = 44.42 mg, and temperature = 23.60 °C. The rates observed in the hydrogen production (1136 µmolh-1g-1) were obtained without costly co-catalyst. The optimized values for hydrogen production include photocatalyst dosage = 50 mg, pH = 7, and time = 5 hours. These features signify the efficient separation of charge carriers between synthesized nanocomposites, resulting in exquisite activities.

Carbon encapsulated CdTe nanorods to execute the enhanced and photo corrosion free hydrogen production

We present carbon-encapsulated CdTe nanorods synthesized through a well-established hydrothermal method. The impact of varying weight percentages of carbon on CdTe nanorods has been explored. XRD, HR-TEM, XPS, Raman and UV-Vis characterization techniques are used to examine the physicochemical and optical properties of prepared compounds. The loading of the carbon layer can be regulated by varying the quantity of sucrose utilized during the synthesis process. The optimized photocatalyst exhibits a superior rate of hydrogen evolution at 247.7 mmol. h−1. g−1cat compared to bare CdTe nanorods. Here, the carbon layer serves a dual purpose as a photocorrosion inhibitor and facilitates electron tunneling for surface reactions. This combined effect of carbon on CdTe is responsible for the observed improvement in the hydrogen evolution rate. As the loading of carbon varies, the activity is aligning closely with the light penetration effect in photocatalysis. Furthermore, we investigated the durability of the optimized photocatalyst, revealing that it retains 89 % of its initial activity even after five cycles. After the activity experiments, essential characterizations such as XRD, Raman and XPS were also analyzed, and the solar to H2 conversion efficiency was computed.

Evaluation of highly active and stable SiO2 supported Fe-based catalysts for the catalytic methane decomposition into COx free hydrogen and CNTs

Catalytic methane decomposition is believed to be an economic and environmental friendly route for the production of COx free hydrogen and high quality carbon nanotubes. However, the development of active and stable catalysts remains a significantly challenging research topic. This study focuses on the development of highly active and stable silica-supported Fe-based catalysts for the thermal decomposition of methane into hydrogen and high quality carbon nanotubes. A series of Fe/SiO2 catalysts with varying Fe loading in the range between 25 wt% and 100 wt% were synthesized by the solution combustion synthesis (SCS) method. The synthesized catalysts were characterized by various bulk sensitive and surface sensitive analytical tools, such as SEM, XRD, HRTEM, BET and Raman spectroscopy. All supported catalysts exhibited comparatively high activity than the unsupported 100 wt% Fe (denoted as 100F) catalyst which was the least active. Moreover, the catalytic activity in terms of methane conversion, methane decomposition rate, growth activities as well as carbon yields increased with an increase in the Fe loading. At an operating temperature of 650 °C and a GHSV of 8000 h−1, the 75FS catalyst, with a composition of 75 wt%Fe/SiO2, demonstrated the highest methane decomposition rate of 0.75gCH4/g-cat.h among the investigated catalysts. Additionally, after achieving initial stability at about 120 min, this catalyst remained active throughout testing on stream for 900 min. TEM and SEM analysis of the spent catalyst showed that the supported 75FS catalyst produced multi-walled carbon nanotubes with uniform diameters of 28 nm and with Id/Ig ratio of 0.454 whereas the unsupported 100F catalyst mainly produced graphene sheets.

A Review on Research and Technology Development of Green Hydrogen Energy Systems with Thermal Management and Heat Recovery

This paper presents a review of recent research and development progress on green hydrogen energy systems and associated thermal management and waste heat recovery technologies. First, hydrogen production methods are briefed. Second, various electrolysis systems used for carbon free hydrogen production from renewable and nuclear resources are discussed. Then, hydrogen utilization using proton-exchange fuel cells is scrutinized. Next, hydrogen energy systems integrated with metal hydride energy storage are elaborated. A focus of this review is on thermal management and process intensification technologies for hydrogen energy systems and integrated metal hydride hydrogen storage technologies. Various process and heat transfer enhancement techniques for heat removal and utilization are presented. Advanced cooling technologies for hydrogen energy systems such as two-phase and boiling for cooling, microchannels for heat removal, CO2 air conditioner and using nanofluids for heat removal are discussed. Finally, heat recovery technologies in green hydrogen energy systems are summarized. This review has also identified future research and technology development needs for green hydrogen energy utilization, thermal management, and heat recovery systems.

Promotion effects of different methods in COx-free hydrogen production from ammonia decomposition

Ammonia can be decomposed to produce exclusively hydrogen and nitrogen so that it could function as a means for hydrogen storage.

Y-Doped BaCeO3 Perovskite-Supported Ru Catalysts for COx-Free Hydrogen Production from Ammonia: Effect of Strong Metal–Support Interactions

The development of highly efficient Ru-based catalysts for NH3 decomposition is necessary to enable the utilization of NH3 as a COx-free H2 carrier. Modulation of the interactions between the basic support materials and Ru particles significantly enhances the performance of Ru-based catalysts for NH3 decomposition. In this study, the strong metal–support interaction (SMSI) interface between the BaCeO3 perovskite support and Ru particles was controlled by yttrium (Y) doping in the range of 0–20 mol %. The substitution of Y3+ into Ce4+ sites improved the reducibility of the support for the removal of lattice oxygen atoms, which promoted the formation of the SMSI interface between the mobile oxygen-deficient suboxide supports and Ru particles. The Ru catalysts supported on Y-doped BaCeO3 exhibited superior activity compared to undoped and other representative Ru catalysts. Moreover, the SMSI shell encapsulating the Ru particles improved the stability of the Y-doped Ru catalyst. This comprehensive study demonstrates that the enhancement in catalytic performance is attributable to facilitated N2 desorption, which is the rate-limiting step for NH3 decomposition over Ru-based catalysts, via the formation of the SMSI interface. These research findings show that the control of the SMSI interface is a promising strategy for designing highly active catalysts to be used in NH3 decomposition.

Synthesis of Yttrium Doped Barium Zirconate/Cerate Electrolyte Materials and Densification Using Conventional and Cold-Sintering Processes

Compared to high temperature SOEC usually based on Yttrium stabilized Zirconia electrolytes, intermediate temperature PCEC allows the production of water free hydrogen and a better chemical stability. Proton conducting perovskite specific materials, such as Barium Indates1, Zirconate or Cerates2 are nearly commercial electrolytes for such devices.This study focuses on the synthesis the characterization and the densification of the BaZr1-xCexY0.1O3- δ 3 powder. At intermediate temperature and under humid atmosphere, hydration process allows diffusion of protonic charges. Such electrolyte material combines a low thermal expansion coefficient and a high protonic conductivity. Two specific stoichiometry’s have been studied, Cerium rich BaZr 0.3 Ce 0.6 Y0.1O3- δ (BZCY361) and Zirconium rich BaZr 0.7 Ce 0.2 Y0.1O3- δ (BZCY721). BZCY361 shows at 550°C, a conductivity level of 2.10- 2 S.cm- 1. However, despite its high protonic conductivity, the cerium rich phase is not stable at high temperature and is torn apart in presence of carbon dioxide.BaZr1-xCexY0.1O3- δ powder has been synthetized by combustion reaction based on nitrate precursors and glycine as organic complexing/fuel agent. The fuel/oxidizer (nitrates) ratio, which is a key parameter4, has been optimized in order to obtain the best purity and crystallinity. The powder is then milled and calcined. The single-phase electrolyte powder is conventionally shaped into pellets and densified A minimal temperature of 1600°C is necessary to obtained a density of 90-95%. In order to reduce the sintering temperature, an intermediate sintering step called "Cold Sintering Process"5 (CSP) has been investigated. In this technic, derived from the hydrothermal method, BCZY powder mixed with a small volume of liquid phase (3-30 wt%) is simultaneously pressed (at 50 to 500 MPa) and heated during a short time period (1-60 min) at low temperatures (100-200°C), leading to dense pellets.In regards to design a complete cell based on this electrolyte, EIS has been performed under hydrogen and air atmosphere. The electrochemical measurements of the samples provided by the different protocols and stoichiometry’s have been compared in order to determine the impact of the CSP and stoichiometry parameters on the ionic conductivity of the material.Acknowledgment: This study, included in the PhD of P. Castellani, was made possible with support from the Franco German ANR-BMBF project (Grant No. ANR-19-ENER-0003-12 [1] Quarez, Eric, Samuel Noirault, Annie Le Gal La Salle, Philippe Stevens, et Olivier Joubert. « Evaluation of Ba2(In0.8Ti0.2)2O5.2−n(OH)2n as a Potential Electrolyte Material for Proton-Conducting Solid Oxide Fuel Cell ». Journal of Power Sources 195 (15), 4923-27 (2010) [2] Thabet, K., Le Gal La Salle, A., Quarez, E., and Joubert, O. “Protonic-Based Ceramics for Fuel Cells and Electrolyzers,” Solid Oxide-Based Electrochemical Devices, Elsevier, pp. 91–122 (2020) [3] Thabet, K., Devisse, M., Quarez, E., Joubert, O., and Le Gal La Salle, A. “Influence of the Autocombustion Synthesis Conditions and the Calcination Temperature on the Microstructure and Electrochemical Properties of BaCe0.8Zr0.1Y0.1O3− δ Electrolyte Material,” Solid State Ionics, 325, pp. 48–56, (2018) [4] Varma, A., Mukasyan, A. S., Rogachev, A. S., and Manukyan, K. V., “Solution Combustion Synthesis of Nanoscale Materials,” Chem. Rev., 116(23), pp. 14493–14586 (2016) [5] Guo, H., Baker, A., Guo, J., and Randall, C. A., “Cold Sintering Process: A Novel Technique for Low‐Temperature Ceramic Processing of Ferroelectrics,” J. Am. Ceram. Soc., 99(11), pp. 3489–3507 (2016) Figure 1

Synthesis of Yttrium Doped Barium Zirconate/Cerate Electrolyte Materials and Densification Using Conventional and Cold-Sintering Processes

Compared to high temperature solid oxide electrolysis cell, usually based on Yttrium stabilized Zirconia electrolytes, intermediate temperature proton conducting electrolysis cell, allows the production of water free hydrogen and a better chemical stability. Proton conducting perovskite materials, such as Barium Indates, Zirconates or Cerates are nearly commercial electrolytes for such devices. At intermediate temperature and under humid atmosphere, hydration process allows diffusion of protonic charges. Such electrolyte material combines a low thermal expansion coefficient and a high protonic conductivity. and The Zirconium rich material BaZr0.7Ce0.2Y0.1O3-δ that shows a conductivity around 10-2 S.cm-1 at 500°C will be compared to the Cerium rich BaZr0.3Ce0.6Y0.1O3-δ material that shows conductivities around 10-4 S.cm-1 at the same temperature.

Methane pyrolysis: CO 2 ‐free production of hydrogen from natural gas

Methane pyrolysis: CO ₂ ‐free production of hydrogen from natural gas

Enhanced methane decomposition over transition metal-based tri-metallic catalysts for the production of COx free hydrogen

In this study, COx-free hydrogen production via methane decomposition was studied over Cu–Zn-promoted tri-metallic Ni–Co–Al catalysts. The catalysts have been prepared by the constant pH co-precipitation method, and the nominal Ni metal loading was fixed at 50 wt % along with other metals at 10 wt% each. The catalyst activity for methane decomposition reaction was examined in a reactor between 400 °C and 700 °C and at atmospheric pressure. Different techniques such as N2-physisorption, X-ray diffraction, H2-TPR SEM, TEM, ICP-MS, TGA, and Raman spectroscopy were applied to characterize the catalysts. The relation between the catalyst composition and their catalytic activity has been investigated. The controlled synthesis has resulted in a series of catalysts with a high surface area. Ni–Co–Cu–Zn–Al was the most active and productive catalyst. Various characterizations indicate that the promotional effects of Cu–Zn interaction were the critical factor in catalysts' activity and stability. Ni–Co–Cu–Zn catalyst gave the highest methane conversion of 85% at 700 °C. Zn addition improves the stability of the catalyst by retaining the active metal size during the decomposition reaction. The catalyst was active for 80 h of stability study. The rapid deactivation of the Ni–Co catalyst was due to the sintering of the catalyst at 650 °C. Moreover, carbon species accumulated during the methane decomposition reaction depend on the catalysts' composition. Zn promotes the growth of reasonably long and thin carbon nanotubes, whereas the diameter of carbon nanotubes on unpromoted catalysts was large.

Ultrasound-assisted decoration of CuOx nanoclusters on TiO2 nanoparticles for additives free photocatalytic hydrogen production and biomass valorization by selective oxidation

• Ultrasound-assisted ultra-wet (US-UWet) impregnation synthetic method is presented. • Mixed cupric and cuprous oxides nanoclusters (< 4 nm) were decorated on TiO 2 P25. • The nanocomposite showed H 2 formation capability under low power UV irradiation. • The additive free oxidation of biomass derived model platform chemicals was studied. • Nanocomposite revealed higher selectivity comparing to P25 for HMF and BnOH oxidation. The herein presented ultrasound-assisted ultra-wet (US-UWet) impregnation synthetic approach was followed in order to avoid the drawbacks of the conventional wet impregnation synthesis. The goal was to homogeneously decorate the surface of the TiO 2 nanoparticles with nanometric sized (< 4 nm) clusters of mixed cupric and cuprous oxides. The physicochemical features of the nanocomposite (TiO 2 CuO x ) were determined by high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and Diffuse reflectance (DR) spectroscopy. TiO 2 CuO x showed an enhanced and continuous capability to generate molecular hydrogen upon low power ultraviolet irradiation. The benchmark commercial TiO 2 P25 did not reveal any H 2 formation under these conditions. TiO 2 CuO x presented also a high efficiency for the additives-free selective partial oxidation of two well established biomass derived model platform chemicals/building blocks, 5-hydroxymethylfurfural (HMF) and benzyl alcohol (BnOH) to the value-added chemicals 2,5-diformylfuran (DFF) and benzyl aldehyde (PhCHO), respectively. The nanocomposite showed higher DFF and PhCHO yield compared to P25.

COx-free hydrogen production via ammonia decomposition over mesoporous Co/Al2O3 catalysts with highly dispersed Co species synthesized by a facile method.

Transition metals have been considered as potential catalysts for ammonia decomposition to produce COx-free hydrogen for fuel cells. However, the facile synthesis of transition metal catalysts with small size active species, high porosity and good structural stability is still a challenge in catalytic NH3 decomposition. Herein, mesoporous Co/Al2O3 catalysts with various cobalt contents were synthesized by a facile modified sol-gel method. The catalyst 15CoAl with 15 at% cobalt content realizes the optimal catalytic NH3 decomposition performance. 92% NH3 conversion at 600 °C is achieved with a gaseous hourly space velocity (GHSV) of 24 000 cm3 gcat-1 h-1 and a hydrogen formation rate of 33.9 mmol gcat-1 min-1 at 600 °C is maintained after a 120 h long-duration stability test. Uniform small cobalt particles with high dispersion are well embedded into the skeleton of the mesoporous Al2O3 matrix. The aggregation of active cobalt species during the high temperature reaction can be effectively prevented by the mesoporous Al2O3 matrix due to the strong interaction between them, thus ensuring a good catalytic performance for ammonia decomposition.

CO2-Free Hydrogen Production by Catalytic Pyrolysis of Hydrocarbon Feedstocks in Molten Ni–Bi

The catalytic decomposition of methane, propane, benzene, and crude petroleum was investigated between 900 and 1000 °C in molten metal bubble column reactors. The conversion to gas phase products a...

Electromagnetic and chemical numerical coupling method in bubbly liquid metal flows for optimization of carbon dioxide free production of hydrogen

Electromagnetic and chemical numerical coupling method in bubbly liquid metal flows for optimization of carbon dioxide free production of hydrogen

Influence of space velocity and catalyst pretreatment on COx free hydrogen and carbon nanotubes production over CoMo/MgO catalyst

The influence of catalyst pretreatment and space velocity in methane decomposition into COx-free hydrogen and carbon nanotubes were investigated over CoMo/MgO catalyst. The reduction of catalyst before methane decomposition leads to a hydrogen production without significant formation of COx (concentration lower than 5 ppm after 25 min of reaction) suitable for its use in fuel cells. However, a high hydrogen space velocity in the pretreatment increased the rate of catalyst deactivation. The CO and CO2 formation rates showed a common trend for all conditions tested: there was a high initial rate and, after 2 min of reaction, there was a lower stabilized rate. The increase in methane space velocity increased the hydrogen formation rate and the degree of carbon nanotubes graphitization. However, it strongly decreases methane conversion, as expected. The use of low hydrogen space velocity, 0.25 h−1, in catalyst pretreatment and high methane space velocity, 8 h−1, in reaction step, provided the highest hydrogen yield and well-structured carbon nanotubes.

振興賞 太陽光発電電力によるCO2フリー水素製造システムの計画・制御手法の開発

振興賞 太陽光発電電力によるCO2フリー水素製造システムの計画・制御手法の開発

Investigation of the 3D hydrogen distribution in zirconium alloys by means of neutron tomography

Abstract The fuel rod claddings in nuclear light water reactors are made of zirconium alloys. Corrosion of these alloys during operation and in particular high temperature oxidation during nuclear accidents results in the production of free hydrogen. The cladding can absorb this hydrogen. It affects the mechanical properties of the cladding material. Hydrogen embrittlement of these materials provides the risk of brittle fracture of the cladding by thermo-shock during emergency cooling. At KIT the behaviour of cladding materials under different hypothetical nuclear accident scenarios was investigated. One focus was on hydrogen absorption and distribution/re-distribution in the alloys. The hydrogen distribution was determined mainly by neutron tomography. Examples for the determination of the 3D hydrogen distribution in cladding tubes after loss of coolant accident simulation tests are given and discussed.

MgFe and Mg–Co–Fe mixed oxides derived from hydrotalcites: Highly efficient catalysts for COx free hydrogen production from NH3

Mg–Fe Layered Double Hydroxide (LDH) with M2+: M3+ 3:1 stoichiometric ratio was synthesized and employed as catalyst precursor for COx-free hydrogen production from ammonia. The resulting catalyst showed good catalytic activity. A series of Mg/Co–Fe layered double hydroxides were synthesized by replacing Mg2+ with Co2+ without disturbing M2+:M3+ ratio. The influence of nature and extent of Co(II) substitution on structure, morphology and surface properties were studied. A systematic study was carried out using these materials as catalyst precursors for ammonia decomposition. BET, XRD, TPR, XPS, CO2-TPD and TEM techniques were used to characterize the synthesized catalysts. These Fe-based catalysts are highly active, highly stable and not promoting any stable surface nitridation during the ammonia decomposition reaction. Among all catalysts, the Mg3Co3Fe2 catalyst showed the highest activity i.e. 100% conversion at 6,000 h−1 and 60% at 50,000 h−1 space velocities at 550 °C. The registered superior catalytic activity was result of the formed specific catalyst's properties like high surface area, high surface Co and Fe atomic concentration and suitable basicity. These Fe-based materials are, cost-effective, easily synthesize and highly stable, thus attractive for large-scale operation.

4-1-2 CO2フリー低温熱化学水素製造に関する研究

4-1-2 CO2フリー低温熱化学水素製造に関する研究