Hydrogen Production Capacity Research Articles

Thermodynamic analysis of a plasma co-gasification process for hydrogen production using sludge and food waste as mixed raw materials

To solve the problem that sludge and food waste are easy to putrefy and cause secondary pollution to air and groundwater, this work proposes a plasma co-gasification for hydrogen model of sludge and food waste and uses experimental data to verify the model. Based on the simulation results, the effects of plasma gasification temperature and steam to feedstock ratio on the performance of sludge + food waste plasma co-gasification process are discussed by sensitivity analysis. The syngas component characteristics, energy upgrade factor and thermodynamic efficiency of each unit of the two processes are studied. The results show that the hydrogen production capacity of co-gasification process of municipal sludge + food waste is 57.43 % higher than that of the industrial sludge + food waste. The H element content in the raw material is a key factor affecting the hydrogen production in the plasma co-gasification process, while the relative balance of H2 and CO content in crude syngas is conducive to improving the hydrogen production capacity in the entire process. The exergy efficiencies of the two processes are 56.57 % and 56.77 % respectively. This study can provide a new concept for both resource utilization and harmlessness of sludge and food waste treatment.

Microporous Transport Layers Facilitating Low Iridium Loadings in Polymer Electrolyte Water Electrolyzers

Minimizing iridium content in the anodic catalyst layer (CL) of polymer electrolyte water electrolyzers (PEWE) is essential for facilitating the needed rapid scale-up of hydrogen production capacity. However, reducing the iridium loading inevitably produces thinner CLs (if not changing the catalyst itself). This can have severe effects on performance and stability, mainly due to the losses in the connectivity of the 3D structure. Microporous layers (MPLs) have the potential to improve the performance and catalyst layer utilization of PEWE cells[1], especially at low Ir-loadings since they minimize the in-plane transport length of the required species (i.e. electric and fluidic transport).In this work, we characterized the 3D structure and transport properties of typical IrO2/TiO2 core-shell PEWE catalyst layers[2] by synchrotron-based ptychographic X-ray laminography (PyXL)[3]. Furthermore, we fabricated CLs at different Ir-loadings between 2.5 – 0.1 mgIr cm-2 depositing them either on the membrane i.e. catalyst-coated membranes (CCM) or on the MPL/PTL i.e. porous transport electrode (PTE). We tested the electrodes in PEWE cells using novel MPLs and standard commercial porous transport layers (PTLs) and compared their electrochemical performance and overpotentials. We observe that ultra-low iridium loadings (0.1 mgIr cm-2) with only relatively small setbacks in performance are possible when using Pt-coated MPLs. Moreover, we correlate the electrochemical results with the 3D structure of the CL by PyXL and the MPL/CL interface by lab-based X-ray tomographic microscopy (Figure 1). Finally, we will discuss the challenges of fabricating low-loaded anodic CLs in CCM and PTE configuration and the advantages of using an MPL in both scenarios.[1] T. Schuler, J. M. Ciccone, B. Krentscher, F. Marone, C. Peter, T. J. Schmidt, F. N. Büchi, Adv. Energy Mater. 2020, 10, 1903216.[2] S. De Angelis, T. Schuler, M. Sabharwal, M. Holler, M. Guizar-Sicairos, E. Müller, F. N. Büchi, Sci Rep 2023, 13, 4280.[3] M. Holler, M. Odstrcil, M. Guizar-Sicairos, M. Lebugle, E. Müller, S. Finizio, G. Tinti, C. David, J. Zusman, W. Unglaub, O. Bunk, J. Raabe, A. F. J. Levi, G. Aeppli, Nature Electronics 2019, 2, 464.Figure 1. Surface renderings from XTM/PyXL and SEM images of porous transport electrodes (PTE, left) and catalyst-coated membranes (CCM, right) of selected samples used in this work. Figure 1

Simultaneous evaluation of criteria and alternatives method-based site selection for solar hydrogen production plant in Inner Mongolia, China

In the context of achieving carbon neutrality, China's demand for renewable energy continues to grow, with the development of solar energy attracting widespread attention. Aiming at the problem that solar energy is not accessible at all times and the storage of excess power, this paper proposes a model for siting a solar hydrogen plant in Inner Mongolia based on Simultaneous Evaluation of Criteria and Alternatives (SECA). Firstly, considering the uniqueness of solar hydrogen production projects (SHPPs), we incorporate the criteria of hydrogen production capacity and local finance into the siting decision model. Secondly, the SECA method is employed to construct a nonlinear multi-objective optimization model, facilitating the direct determination of criterion weights and enhancing decision-making efficiency. Third, the convergence change of the coefficient β in the SECA method is used to rank the candidate cities by solving the optimization model to produce stable results. Finally, this study verifies the validity of the model used through sensitivity and comparative analyses. The results show that Chifeng is the best location for solar hydrogen production considering the three most important factors are hydrogen production capacity (11.7%), average humidity (12.4%) and average temperature (14.46%).

Alkali-buffering effect to increase hydrogen production on co-fermentation of citrus agroindustrial waste

Fermentation operational pH is a critical parameter for hydrogen production and aiming to improve the pH stability in the process, supplementation with buffering agents can be an alternative. The effect of two buffering agents, sodium bicarbonate (NaHCO3) and calcium carbonate (CaCO3), in hydrogen production from citrus peel waste (CPW) and citrus processing wastewater (CPWW) was evaluated, in assays carried out in batch reactors. The calcium carbonate was identified the buffering agent with the most significant positive effect on H2 production. The effect of CaCO3 concentration (1.0–4.0 g L−1) with variations in the citrus peel waste (7.0–25.0 gTVS.L−1) and citrus processing wastewater (1.0–3.0 gCOD.L−1) concentrations were evaluated through an experimental design. In the assays with CaCO3 and NaHCO3, the hydrogen production was 1099.7 mL L−1 and 517.3 mL L−1, respectively, representing an increase of 176.8 % and 30.2 % when compared to the control assay (397.4 mL L−1), and CaCO3 was identified as the best alternative for alkalinizing the process. Through experimental design assays the high importance of the adjustment between buffering capacity and substrate availability for hydrogen production was verified. Higher H2 production (940.0 mL L−1) was obtained in the assay with 2.5 g.L-1 of CaCO3, 16.0 gTVS.L-1 of CPW, 2.0 gCOD.L-1 of CPWW, and 3.5 gTVS.L−1 of inoculum sludge, resulting in a gCaCO3.g−1CHO ratio of 0.45. For the assay with the highest hydrogen production, butyric acid (1752.1 mg L−1) and acetic acid (1768.3 mg L−1) were the metabolites in the highest concentration and a relative abundance higher than 90 % of Clostridium sensu stricto was identified. A maximum energy potential of 634.91 MJ t−1 of CPW was obtained with an estimated electricity generation potential of up to 3.2 million MWh per year.

Hydrogen station location optimization coupling hydrogen sources and transportation along the expressway

The appropriate siting of hydrogen refueling stations (HRSs) can contribute to reducing hydrogen costs and promoting the widespread adoption of hydrogen fuel cell vehicles (HFCVs). This study integrates hydrogen sources and transportation, aiming to minimize the unit hydrogen cost. Two models for hydrogen station siting along the expressway are established. For the selection of feasible station siting schemes under discrete conditions, we design a screening process and algorithm Taking a specific highway section as a case study, both models are optimized, resulting in the unit hydrogen cost of 50.44 CNY/kg and 51.69 CNY/kg, respectively. Optimization verification is conducted, with percentage variances of 6.61 % and 18.77 %, respectively. Furthermore, the study delves into the impacts of different hydrogen demand, hydrogen production capacities, and the maximum allowable spacing between HRSs on station siting for both models. This research provides significant insights for hydrogen station siting along the expressway.

Progress of Algaculture technology as Biofuel

As the problem of climate change becomes more and more serious, improving the carbon emission situation will be an effective way to solve various climate problems. Algal biofuels can build a complete carbon cycle and reduce carbon emissions. In this paper, the conditions required for microalgae cultivation and how diverse factors play a role in the growth rate and yield of microalgae were reviewed. And show how different factors like pH value, illumination, temperature, medium of culture, and nutrients in the medium affect the content of different substances in the final microalgae to help breed the matching microalgae. Macroscopically, this paper introduces both open raceway ponds and photobioreactors as microalgae cultivation systems and their respective characteristics. Microalgae will produce higher lipid content and hydrogen production capacity in different acid-base environments, respectively, and provide a nitrogen-deficient environment to further increase lipid production. The two-stage hybrid system combining an open raceway pond and photobioreactor has more obvious advantages in terms of growth rate and yield.

Spin-polarization and crystal structure engineering enhanced photocatalytic H2 production and photoluminescence properties in cobalt-doped CsPbBr3

In this study, the effect of Co doping in CsPbBr3 perovskite on phase transition and photocatalytic hydrogen production under a magnetic field was studied. Square CsPbBr3 nanoparticles with a dimension of 30–40 nm have been synthesized by the hot injection method. Rietveld refinement on the XRD pattern revealed the phase transition from cubic to orthorhombic after Co doping. The addition of 3%Co to CsPbBr3 resulted in a significant hydrogen production capacity of 3500 μmol/g in 4 h, with the maximum hydrogen production rate of 1042.11 μmol/g·h in the first hour, which was 1.80 times the maximum hydrogen production rate of bare CsPbBr3 (581.66 μmol/g·h). Notably, the photocatalytic H2 production of 3%Co: CsPbBr3 perovskite is significantly enhanced by applying an external magnetic field. Under the magnetic field of 2 T, the hydrogen production capacity of Co: CsPbBr3 increased to 5300 μmol/g in 4 h, with the maximum hydrogen production rate of 1828.36 μmol/g·h in the first hour, being 3.14 times the maximum hydrogen production rate of CsPbBr3 without magnetic field. The corresponding mechanism is systematically investigated by a vibrating-sample magnetometer, Electron paramagnetic resonance, UV–visible absorption, and photoluminescence spectra. The photocurrent and EIS were applied to investigate the charge-transfer kinetics of Co–CsPbBr3. The excellent photocatalytic H2 production efficiencies are because the doping of magnetic Co into highly polarized orthorhombic CsPbBr3 increased the number of spin-polarized photo-generated carriers while applying magnetic field provided spin polarization and more electron transport channels, suppressing the recombination efficiency of electrons and holes. Manipulating spin-polarized electrons in highly polarized orthorhombic photocatalytic semiconductors provides an effective strategy to boost photocatalytic H2 production efficiencies.

Multi-criteria thermoeconomic optimization of a geothermal energy-driven green hydrogen production plant coupled to an alkaline electrolyzer

Among the various technologies for hydrogen production, the renewable energy driven water electrolysis has emerged as a favorable method. In this respect, the present research proposes and analyses a novel and efficient medium-temperature driven geothermal system for green hydrogen production. An alkaline electrolyzer is deployed for hydrogen production which is powered by a double flash steam geothermal power cycle. To boost the power generation (and hence the hydrogen production amount) the double flash cycle is equipped with a self-superheating process, which superheats the saturated vapor at turbine inlet without using another external heat source. Thermodynamic evaluations, based on exergy concept, along with economic analysis are carried out to assess the hydrogen production amount, plant exergy efficiency and total cost rate, and the unit hydrogen price. In order to represent a comprehensive investigation of the plant performance, parametric analyses along with single- and multi-criteria optimizations were conducted. The results revealed that, for 1kg/s of geothermal brine, the capacity of hydrogen production of the proposed plant is ∼1.5−3kg/h under various operating conditions. It is found that, under multi-objective optimum operating conditions, the plant yields 12.63% exergy efficiency and its total cost rate is calculated to be 10.42 $/h. However, if the plant is to be optimized for maximum exergy efficiency, the value of 14.25% is achievable which will result in increment of total cost rate to 11.97 $/h.

Synergistic catalytic biomass-H2O gasification for H2 production and biochar etching mechanism: Experimental and DFT studies

Biomass-H2O gasification facilitated by multi-metal synergistic catalysis for H2 production. Oxygen transfer, carbon dissolution, lateral/vertical etching mechanism, and hydrogen production capacity of biomass self-contained K and added Ni catalytic gasification were studied through biomass loaded with K and Ni pyrolysis, biochar gasification experiments, and DFT calculations. The H2 yield from KNi catalytic gasification was 67.09 mmol/g (increased by 13.51%). Driven by *OH, K migrates and transforms from the inside of the carbon matrix to form active sites (CK), increasing carbon defects (40–50%) and reactivity. The vertical etching ability of Ni on biochar is enhanced from outside to inside (forming NiC and CK to reduce carbon dissolution energy barrier) and the gasification reaction rate is increased. The competition between the strong attraction of Ni on OH and the van der Waals force of K on OH leads to a 7.7% increase in the energy barrier of the rate-determining step (H transfer). The work enhances the understanding of the multi-metal catalytic gasification of rich H2 and provides a foundation for developing catalytic gasification technology.

Steam reforming of methane over nickel-aluminum spinel-derived catalyst

Despite steam reforming of methane (SRM) has been the dominant way to produce hydrogen in industrial owing to its large hydrogen production capacity, easy accessibility of feedstocks and relative low cost, the development of high-efficient catalysts is still of great significance. In this work, we report the synthesis, characterizations and evaluation of Nickel-aluminum spinel (NiAl2O4) catalyst in SRM reaction. Compared with Ni/γ-Al2O3 catalyst prepared by impregnation, NiAl2O4 presents higher methane conversion. Virous of characterizations exhibit NiAl2O4 possesses higher distribution of Ni and smaller Ni nanoparticle size, which is one of advantages for its high activity. Another vital reason is the generation of oxygen vacancies in spinel during the reduction, which is beneficial for the activation of water. Moreover, NiAl2O4 catalyst shows extremely stability without obvious deactivation in 160 h. This study illustrates that the construction of catalyst with high activity and stability via NiAl2O4 spinel and reals its high activity origination.

Enhancing biohydrogen production by peanut shell carrier assisted fermentation at different hydraulic retention time

The microbial immobilization and suitable hydraulic retention time (HRT) are conducive to maintain the biomass for further prompting the hydrogen production efficiency. In this study, peanut shell was employed as carriers to investigate the hydrogen production enhancement and the promotion mechanism at different HRTs with plastic pellet carrier as control. Both of the over-acid phenomenon and the operational stability decreasing occurred when HRT was shorter or longer than 6 h (HRT = 2 h, 4 h, or 8 h) in this study. When peanut shell was used as carrier, the maximum H2 yield of 1.7 L and H2 production rate of 0.58 L/L/d were obtained at HRT of 6 h, which were nearly 20 % and 15 % higher than that of plastic pellet as carriers, respectively. The hydrogen production system with peanut shell as carriers had better hydrogen production capacity and immobilized effect, since peanut shell provided a supplementary substrate for the growth and metabolism of hydrogen producing bacteria, and buffered the acidity of the system. This study provided an application for immobilization technology and the industrialization of bio-hydrogen production.

Interfacial Charge Transfer Effects of MoS2/α-Fe2O3 Nano-Heterojunction and Efficient Photocatalytic Hydrogen Evolution under Visible-Light Irradiation.

Researchers have made efforts to develop high-productivity photocatalysts for photocatalytic hydrogen production to reduce the problem of a lack of energy. Bulk semiconductor photocatalysts mainly endure particular limitations, such as low visible light application, a quick recombination rate of electron-hole pairs, and poor photocatalytic efficiency. The major challenge is to improve solar-light-driven heterostructure photocatalysts that are highly active and stable under the photocatalytic system. In this study, the proposed nano-heterojunction exhibits a great capacity for hydrogen production (871.2 μmol g-1 h-1), which is over 8.1-fold and 12.3-fold higher than that of the bare MoS2 and bare α-Fe2O3 samples, respectively. It is demonstrated that the MoS2/α-Fe2O3 heterojunction gives rise to an enhanced visible light response and accelerated photoinduced charge carrier separation. This work provides an improved visible light absorption efficiency and a narrowed energy band gap, and presents a "highway" for electron-hole pairs to promote transfer and inhibit the combination of photoinduced charge carriers for the utilization of nano-heterojunction photocatalysts in the field of hydrogen production.

Decarbonization of Former Lignite Regions with Renewable Hydrogen: The Western Macedonia Case

For lignite intense regions such as the case of Western Macedonia (WM), the production and utilization of green hydrogen is one of the most viable ways to achieve near zero emissions in sectors like transport, chemicals, heat and energy production, synthetic fuels, etc. However, the implementation of each technology that is available to a respective sector differs significantly in terms of readiness and the current installation scale of each technology. The goal of this study is the provision of a transition roadmap for a decarbonized future for the WM region through utilizing green hydrogen. The technologies which can take part in this transition are presented, along with the implementation purpose of each technology, and the reasonable extension that each technology could be adopted in the present context. The WM region’s limited capacity for green hydrogen production leads to certain integration scenarios, with regards to the required hydrogen, electrolyzer capacities, and required power, whereas an environmental assessment is also presented for each scenario.

Hydrogen production by visible light photocatalysis with Chl@g-C3N4/Ti3C2Tx S-scheme heterojunction

Sustainable conversion of solar energy to hydrogen energy by photocatalytic splitting of water through the use of semiconductor photocatalytic materials is considered to be a promising and sustainable alternative proposal to replace conventional fossil fuels. However, efficient solar-driven photocatalytic hydrogen production has remained a great challenge due to the prevailing problems of existing semiconductor photocatalytic materials. It is shown that constructing heterostructures is a very powerful way to improve the photocatalytic hydrogen production capacity of composites under visible light. Therefore, in this work, an organic heterojunction structure based on chlorophyll (Chl) molecules and graphitic carbon nitride (g-C3N4) is reported and exploited for efficient solar energy-driven photocatalytic hydrogen evolution reaction (HER). Meanwhile, noble metal-free photocatalysts were successfully constructed with Ti3C2Tx MXene nanosheets through a simple stepwise complexation process of Chl, g-C3N4, and Ti3C2Tx for the achievement of HER for the photocatalytic decomposition of water. The results show that the optimal Chl@g-C3N4/Ti3C2Tx organic heterojunction composite has a remarkably advanced HER performance of 131 μmol/h/gcat, as compared with the traditional Chl@Ti3C2Tx and g-C3N4/Ti3C2Tx composites. The results provide new ideas for exploring MXene based catalysts for highly efficient conversion of solar energy.

Enhanced morphological maintenance and redox stability by dispersing nickel ferrite into silica matrix for chemical looping hydrogen production via water splitting

Chemical looping hydrogen production (CLHP) is widely regarded as a clean and efficient route for high purity hydrogen production. However, a huge barrier is how to avoid serious deactivation caused by sintering and agglomeration of oxygen carriers. A novel fabrication process of highly dispersing NiFe2O4 into silica matrix is proposed. The oxygen carriers of NiFe2O4 completely dispersed over silica matrix (NFSM) are successfully synthesized. The characterizations, hydrogen production capacity and cycle redox performance of oxygen carriers are further investigated. The results illustrate that NiFe2O4 active components are homogeneously dispersed on the silica matrix without any impurities. NFSM demonstrates the highest reactivity with CO as well as the greatest hydrogen production of 296 mL/g due to the strong confinement effect of silica matrix and good particle dispersion. The porous silica matrix offers large amounts of channels for the lattice oxygen transport and effectively prevents Fe and Ni cations outward migration to particle surface, which actually inhibits the larger clusters and sintering. NFSM can keep stable hydrogen production of approximately 290 mL/g during the cyclic experiments. Briefly, the innovation method of embedding active component into well-established silica matrix supports contributes to the enhanced anti-sintering properties and redox stability of oxygen carriers.

Capacity configuration optimization for green hydrogen generation driven by solar-wind hybrid power based on comprehensive performance criteria

Green hydrogen generation driven by solar-wind hybrid power is a key strategy for obtaining the low-carbon energy, while by considering the fluctuation natures of solar-wind energy resource, the system capacity configuration of power generation, hydrogen production and essential storage devices need to be comprehensively optimized. In this work, a solar-wind hybrid green hydrogen production system is developed by combining the hydrogen storage equipment with the power grid, the coordinated operation strategy of solar-wind hybrid hydrogen production is proposed, furthermore, the NSGA-III algorithm is used to optimize the system capacity configuration with the comprehensive performance criteria of economy, environment and energy efficiency. Through the implemented case study with the hydrogen production capacity of 20,000 tons/year, the abandoned energy power rate will be reduced to 3.32% with the electrolytic cell average load factor of 64.77%, and the system achieves the remarkable carbon emission reduction. In addition, with the advantage of connect to the power grid, the generated surplus solar/wind power can be readily transmitted with addition income, when the sale price of produced hydrogen is suggested to 27.80 CNY/kgH2, the internal rate of return of the system reaches to 8% which present the reasonable economic potential. The research provides technical and methodological suggestions and guidance for the development of solar-wind hybrid hydrogen production schemes with favorable comprehensive performance.

Solid Oxide Cell Technology for Power Generation, Hydrogen Production and Energy Storage

The progress in maturation of solid oxide cell technology has led to development of new applications that would explode its presence in many areas, far beyond power generation. The solid oxide cell technology has the potential to have a formidable presence in production of hydrogen and, eventually, long duration storage of electric power.Following the successful operation of a 200 kW SOFC system under a project supported by Department Energy/NETL, FuelCell Energy (FCE) is pursing the development of SOC based plant configurations from subMW to electrolysis, and further, to energy storage.Multi-faceted evolution of the technology has been underway since the earlier demonstration of SOFC power plant. FCE has developed state-of-the-art lightweight Compact SOFC Architecture (CSA) stacks that are packaged in compact modules with adaptability for use in a variety of configurations and capacities. The CSA stacks can operate directly on a variety of fuels - natural gas, biogas, and hydrogen- without any modification. FCE’s existing fuel cell pilot manufacturing line for CSA cells and stacks includes robotics and automation such as cell screen printing, interconnect subassembly, seal application, QC, as well as stack assembly and conditioning. Via a design for manufacturing approach, as well as focus on minimization of raw material, recent detailed cost studies show a path to low factory stack production cost (<100/kW) at high volumes (1,000 MW/year). The large market existing for power generation equipment, in the range of 200-300kW, is a significant driver for development of high efficiency SOFC products that would easily cater to early-adopters prior to wide-spread acceptance. The accelerated interest in hydrogen as the fuel source will widen the market for SOFC deployment even more. Under a project supported by DOE, FCE is working on design of MW-class SOFC power plants as future extension of the subMW SOFC plant products.FCE is developing a first-of-a-kind 250kW Solid Oxide Electrolyzer Cell (SOEC) system with the hydrogen production capacity of 150kg/day. The overarching goal of the project is to verify that the integration of Solid Oxide Electrolysis Cell (SOEC) systems within nuclear plants will maximize the plants’ efficiency and flexibility and will increase their revenue by switching between electric power generation and hydrogen production. Hybrid nuclear-hydrogen production operations are expected to help the present and future nuclear plants diversify and increase profitability.The 250kW SOEC system is planned to be demonstrated and operated at Idaho National Laboratory (INL). The project will culminate in verification and validation testing and solidify SOEC technology as a low cost and efficient means for hydrogen production integrated within the nuclear power plant environment. The SOEC system will be interfaced with a High-Level front-end Controller (HLC) simulating communications from a nuclear plant and the electric grid. The HLC will determine an optimized hydrogen production schedule to meet all contractual obligations, while maximizing revenue from the integrated operations.FCE is also developing energy storage systems based on the Company’s Solid Oxide Fuel Cell (SOFC) technology. Reversible Solid Oxide Fuel Cell (RSOFC) technology is suitable for medium to long-duration energy storage achieving high round trip electric efficiencies near 70% (electricity-in to electricity-out) at an expected levelized cycle cost of ≤ $0.05 / kWh-cycle.FCE is currently conducting operational tests of an RSOFC prototype system to accomplish the of validation and verification of engineering/pilot-scale RSOFC technology in a relevant environment. A bread-board pilot demonstration system is being utilized to verify cell materials and stack design improvements as well as to validate power electronics and system control strategies that will be utilized for optimization of efficiency, transient response, and lifetime characteristics.

Technology Development for Hydrogen Production Using Nuclear Energy

Nuclear energy is a low-carbon energy source which can provide both electricity and high-temperature heat. Nuclear-based hydrogen production offers a unique opportunity to mitigate carbon emissions. Canadian Nuclear Laboratories (CNL) has been actively developing technologies for nuclear hydrogen production. This poster will highlight CNL’s capability and achievements on the Cu-Cl thermochemical process (CNL trademarked as HCuTECTM) and Solid oxide electrolysis (SOE).HCuTECTM has four main steps in the process: Electrolysis, Separation, Hydrolysis and Thermolysis. The maximum temperature of the HCuTECTM process is 530 oC, which is lower than other thermochemical processes and makes its coupling with some small modular reactors and the supercritical water nuclear reactor ideal since these reactors can supply heat above 600 oC. CNL has extensively studied these individual steps and demonstrated an integrated laboratory system (shown in Figure 1) with a hydrogen production capacity of 100 g/d. CNL is interested in scaling up the process with industrial partners.SOE is also being researched and advanced for hydrogen and clean fuel production at CNL. Current effort is focused on the materials development for oxygen conducting cells. Several CNL cells were made with in-house materials and tested on single cell stations. Preliminary results of CNL cells showed very promising performance for hydrogen production. In the meantime, CNL is assessing the economic benefit of different options to integrate SOE with high-temperature nuclear reactors for both hydrogen and clean fuel production. Figure 1

Thermochemical production of green hydrogen using ferrous scrap materials

Thermochemical water splitting is one of the methods to produce green hydrogen. In this study, metal scrap is used to split water by thermochemical process in a packed-bed reactor. Hydrogen production conditions are optimized by varying the particle size of the metal wastes in the range of 250 μm to greater than 1000 μm and the temperatures from 900 °C to 1200 °C. The maximum yield of hydrogen obtained is ∼500 mL of H2 per gram of the scrap sample. This study demonstrates that the discarded metal wastes can be utilized as feed-materials for thermochemical production of green hydrogen. The process has good conversion efficiency and is a promising solution for both metal waste management and the production of green hydrogen. Medium size metal particles show higher hydrogen production capacity compared to both smaller (<250 μm) and larger (600–1180 μm) size particles.

Isolation and characterization of Enterococcus faecalis isolate VT-H1: A highly efficient hydrogen-producing bacterium from palm oil mill effluent (POME)

Facultative hydrogen-producing bacteria hold immense potential for fermentative hydrogen and valuable metabolite production. In this study, a mesophilic hydrogen-producing bacterium was isolated from palm oil mill effluent (POME) and identified as Enterococcus faecalis isolate VT-H1 using hybrid sequencing technologies. Our investigation encompassed the growth of the isolate and its capacity for hydrogen and volatile fatty acid (VFA) production. The results revealed that optimal growth occurred when glucose was utilized at 37 °C and initial pH of 7.0, resulting in a final OD600 of 2.58. The isolate demonstrated exceptional hydrogen production capabilities, achieving a maximum cumulative hydrogen yield of 2.22 mol-H2/mol-glucose at 30 °C and pH 7.0, outperforming previously reported E. faecalis strains by 5.84-fold. Kinetic analysis revealed favorable parameters for hydrogen production at 30 °C, with maximum hydrogen production (Hm = 2.63 mol-H2/mol-glucose), maximum hydrogen production rate (Rm = 0.03 mol-H2/mol-glucose·h), and lag-phase time (LPT = 18.34 h). Additionally, E. faecalis isolate VT-H1 exhibited significant butyric acid production (63.0 mM) alongside acetic acid (7.0 mM). Genome analysis unveiled the presence of key enzymes associated with hydrogen production, including formate hydrogen lyase (FHL) complex with formate dehydrogenase subunit alpha (FDH-α), bidirectional [NiFe] hydrogenase, NADH-dependent oxidoreductase subunit E, and NADH-quinone oxidoreductase subunit F. Moreover, genes associated with butyric acid production were also identified. These findings highlight the potential of E. faecalis isolate VT-H1 as a promising candidate for sustainable hydrogen and VFA production. Its unique characteristics, distinct genetic profile, and exceptional hydrogen and VFA production capabilities bring exciting opportunities for future biotechnological applications and further research to optimize and scale-up its potential for industrial use.