Potential Hydrogen Research Articles

Aluminum-incorporation activates vanadium carbide with electron-rich carbon sites for efficient pH-universal hydrogen evolution reaction

Vanadium carbide (VC) is the greatest potential hydrogen evolution reaction (HER) catalyst because of its platinum-like property and abundant earth reserves. However, it exhibits insufficient catalytic performance due to the unfavorable interaction of reaction intermediates with catalysts. In this work, using NH4VO3 as the main raw material, the flow ratio of CH4 to Ar was accurately controlled, and a non-transition metal Al-doped into VC (100) nano-flowers with carbon hybrids on nickel foams (Al-VC@C/NF) was prepared for the first time as a high-efficiency HER catalyst by chemical vapor carbonization. The overpotential of Al-VC@C/NF catalysts in 0.5 M H2SO4 and 1 M KOH at a current density of 10 mA cm−2 are only 58 mV and 97 mV, respectively, which are the best HER performance among non-noble metal vanadium carbide based catalysts. Simultaneously, Al-VC@C/NF exhibits small Tafel slope (45 mV dec-1 and 73 mV dec-1) and excellent stability in acidic and alkaline media. Theoretical calculations demonstrate that doped Al atoms can induce electron redistribution on the vanadium carbide surface to form electron-rich carbon sites, which significantly reduces the energy barrier during the HER process. This work provides a new tactic to modulate vanadium-based carbons as efficient HER catalysts through non-transition metal doping.

Li-decorated bilayer borophene as a potential hydrogen storage material: A DFT study

Two-dimensional (2D) materials have recently attracted much attention in the field of hydrogen storage, owing to their beneficial properties such as high surface-to-volume ratio and light weight. Motivated by recent experimental developments of bilayer borophene (BL) sheets, we investigate the suitability of hydrogen storage on Li-decorated BL via density functional theory (DFT) calculations. The H2 molecules are adsorbed on BL sheet via weak physisorption. By decorating BL with Li atoms, its hydrogen storage performance has been improved. We find that Li atoms can firmly adsorb on the substrate without forming clusters. Meanwhile, the Li-decorated structure exhibits good stability, verified by molecular dynamics calculations. Remarkably, in the fully loaded case, the compound obtains a 6.08 wt% H2 content and 0.13 eV/H2 average adsorption energy, which is promising for onboard hydrogen storage. Furthermore, electronic structure analysis reveals the electrostatic nature of interactions between the H2 molecules and the protruding Li atoms on BL sheets, which originates from polarization and orbital hybridization. Overall, our results suggest that Li-decorated BL is a promising candidate for potential hydrogen storage applications, and contribute to a better understanding of bilayer materials for hydrogen storage.

Differences in Facial Skin Acidity Levels of Nurses in Sebelas Maret University Hospital, Before and After Surgical Mask Use During the COVID-19 Pandemic

Background: Indonesia has reported more than 4 million confirmed COVID-19 cases as of November 2021. This has led to an increase in the use of personal protective equipment (PPE), for example, surgical masks in hospitals, especially referral hospitals for COVID-19 patients. The Potential Hydrogen (pH) or level of acidity plays an important role in the body's physiological functions and regulates the formation of an epidermal barrier (stratum corneum). Thus, the use of surgical masks is able to influence the pH of human skin. This study aimed to determine the difference in facial skin acidity (pH) levels of nurses at Sebelas Maret University Hospital before and after surgical mask use.
 Methods: The study utilized a cross-sectional observational method and was conducted at the Sebelas Maret University Hospital, Surakarta. A total of 55 subjects were involved in this study, and each subject’s facial skin Potential Hydrogen (pH) was measured before and after surgical mask use. Subsequently, all data were analyzed with a T-test using SPSS 21.00, and a p-value <0.05 indicated statistical significance.
 Results: The results showed facial skin pH increased after surgical mask use for nurses at the Sebelas Maret University Hospital (p = 0.000).
 Conclusion: An increase in the physiological value of skin pH was observed in the nurses of Sebelas Maret University Hospital after surgical mask use.

Evaluation of Soil Suitability for Sesame (Sesamum Indicum) Farming in Gassol Local Government Area of Taraba State, Nigeria

This study evaluates the soil suitability for sesame (Sesamum indicum) farming in Gassol Local Government Area of Taraba State. The specific objectives of the study were to identify the suitable soil for sesame farming in Gassol Local Government Area of Taraba using expert Knowledge, to determine the concentration of soil nutrients for sesame farming in Gassol LGA and to compare the level of soil suitability for Sesame farming in Gassol LGA with that of FAO. The expert questionnaires were used to identify the preferred nutrients for sesame farming. The Analytic Hierarchy Process (AHP) was applied to determine the weight of the different soil nutrients by pairwise comparison matrix. The soil samples were collected from the twelve (12) political wards of the study area. The soil samples taken from each ward were air dried, crushed and sieved using a 2 mm sieve and analysed using standard soil analytical procedures at the Modibbo Adama University of Technology (MAUTECH) Yola. Soil pH was measured (soil: water ratio, 1:2) using a pH metre; total N content was determined by flame photometer. The study revealed through the pairwise comparison matrix that favourable average nitrogen in the area ranked first among the nutrients, followed by potassium, phosphorus, sulphur, electrical conductivity, organic matter, organic carbon and potential hydrogen. The Consistency Ratio (CR) of 0.05 was consistent with the experts’ judgement in determining the preference of soil nutrients for sesame farming in the Gassol area. The laboratory results indicated that potential hydrogen (6.0), electrical conductivity (0.2) and sulphur (5.5) are low in soil nutrients for farming sesame in the study area based on the Food and Agricultural Organisation (FAO 1976) standard. It further shows that organic carbon (0.5) and nitrogen (0.1) are very low in the soil for sesame farming in the study area while potassium (10.5) and organic matter (2.0) are high in the soil nutrient content of the study area. It was recommended that to ensure optimal sesame production, there is a need for awareness by farmers of the suitable site for sesame farming, and farmers need adequate knowledge of the appropriate fertiliser for sesame farming to improve the soil where the nutrients are low, It further recommends for access to farm inputs such as credit facilities, fertiliser, improve seeds and other infrastructural development for farmers.

New model of long-term changes in spatiotemporal patterns of water quality across Shatt-Al-Arab River by applying GIS technique, from 1976 to 2020

PurposeUsing a combination of the geographical information system (GIS) and the Canadian water quality index (WQI), the current study sought to provide a long-term general assessment of the water quality of the Shatt Al-Arab River (SAAR), focusing on its suitability for living organisms. Likewise, SPSS statistics was used to develop a nonlinear WQI regression model for the study area.Design/methodology/approachThe study required four decades of data collection on some environmental characteristics of river water. After that, calculate the WQI and conduct the spatial analysis. Eight variables in total, including water temperature, dissolved oxygen, potential hydrogen ions, electrical conductivity (EC), biological oxygen demand, turbidity, nitrate and phosphate, were chosen to calculate the WQI.FindingsThroughout the study periods, the WQI values varied from 55.2 to 79.83, falling into the categories of four (marginal) and three (fair), with the sixth period (2007–2008) showing the most decline. The present research demonstrated that the high concentration of phosphates, the high EC values, and minor changes in the other environmental factors are the major causes of the decline in water quality. The variations in ecological variables' overlap are a senior contributor to changes in water quality in general. Notably, using GIS in conjunction with the WQI has shown to be very effective in reducing the time and effort spent on investigating water quality while obtaining precise findings and information at the lowest possible expense. Calibration and validation of the developed model showed that this model had a perfect estimate of the WQI value. Due to its flexibility and impartiality, this study recommends using the proposed model to estimate and predict the WQI in the study area.Originality/valueEven though the water quality of the SAAR has been the subject of numerous studies, this is the only long-term investigation that has been done to evaluate and predict its water quality.

ESTUDO COMPARATIVO ENTRE MÉTODOS DE ANÁLISE DA FRENTE DE CARBONATAÇÃO EM ESTRUTURAS DE CONCRETO

Being one of the most common pathological manifestations in reinforced concrete structures, carbonation can cause numerous problems in buildings, especially reinforcement corrosion. In this dynamic, the purpose of this article is to replicate a hypothetical deducible method of testing the carbonation front in reinforced concrete structures, based on an Italian model (Carbontest), having as an exploratory descriptive objective, since the main purpose was to compare the depth of the carbonation front between the “Italian” model and the current destructible method used in Brazil, so that the theoretical and practical means for obtaining data for analysis are initially presented. For the execution of the proposed model, a prototype was produced for sample collection and, from this sample, the carbonation front was determined by the pH indicator (hydrogenion potential): phenolphthalein, which provided, in comparison to the method conventional, an average variation of 2.7%, demonstrating that the application of the method of less impact is acceptable, due to the fact that it provides less destructible effect on the structures, ease of repair of the perforation and agility of the test.

Post‐synthetic modifications in metal–organic frameworks for high proton conductivity

AbstractA myriad of metal ions and organic linkers can be used to produce metal–organic frameworks (MOFs) with varied functionalities, porosities, and dimensionalities. Such diversity has garnered significant research interest, particularly in leveraging MOFs as proton conductors for fuel cells. One effective approach involves introducing guest molecules into MOF pores. These molecules serve either as proton carriers or as proton‐conducting media through potential hydrogen bonding networks. This review offers an organized overview of key methodologies historically employed to achieve superprotonic conductivity in MOFs. The article systematically categorizes these tactics into three primary groups: guest molecule encapsulation, modulation at metal‐coordination sites, and ligand functionalization. We succinctly discuss the roles of proton carriers, conducting media, and the overall MOF framework, emphasizing the significance of each strategy's application. In conclusion, we provide insights into the future development of MOFs as proton conductors, rooted in the categorization and conceptual understanding of these strategies.

Multi-criteria site selection workflow for geological storage of hydrogen in depleted gas fields: A case for the UK

Underground hydrogen storage (UHS) plays a critical role in ensuring the stability and security of the future clean energy supply. However, the efficiency and reliability of UHS technology depend heavily on the careful and criteria-driven selection of suitable storage sites. This study presents a hybrid multi-criteria decision-making framework integrating the Analytical Hierarchy Process (AHP) and Preference Ranking Organisation Method for Enrichment of Evaluations (PROMETHEE) to identify and select the best hydrogen storage sites among depleted gas reservoirs in the UK. To achieve this, a new set of site selection criteria is proposed in light of the technical and economic aspects of UHS, including location, reservoir rock quality and tectonic characteristics, maximum achievable hydrogen well deliverability rate, working gas capacity, cushion gas volume requirement, distance to future potential hydrogen clusters, and access to intermittent renewable energy sources (RESs). The framework is implemented to rank 71 reservoirs based on their potential and suitability for UHS. Firstly, the reservoirs are thoroughly evaluated for each proposed criterion and then the AHP-PROMETHEE technique is employed to prioritise the criteria and rank the storage sites. The study reveals that the total calculated working gas capacity based on single-well plateau withdrawal rates is around 881 TWh across all evaluated reservoirs. The maximum well deliverability rates for hydrogen withdrawal are found to vary considerably among the sites; however, 22 % are estimated to have deliverability rates exceeding 100 sm3/d, and 63 % are located within a distance of 100 km from a major hydrogen cluster. Moreover, 70 % have access to nearby RESs developments, with an estimated cumulative RESs capacity of approximately 181 GW. The results highlight the efficacy of the proposed multi-criteria site selection framework. The top five highest-ranked sites for UHS based on the evaluated criteria are the Cygnus, Hamilton, Saltfleetby, Corvette, and Hatfield Moors gas fields. The insights provided by this study can contribute to informed decision-making, sustainable development, and the overall progress of future UHS projects within the UK and globally.

Optimizing micro-diffusion flame energy density and stability through the application of magnetic fields: A numerical study

Ammonia, a potential hydrogen energy carrier, offers high energy density as a carbon-free fuel, yet its application in micro burners is limited by flame instability. To capitalize on this energy potential, this study innovatively employs a magnetic field to enhance micro-flame stability, marking a novel approach to harnessing the benefits of ammonia. Our investigations into micro-diffusion flames, fueled by ammonia and methane, reveal that the magnetic field not only reduces axial velocity and leading to a back-flow zone, but also directly correlates with peak temperatures and maximal heat release rates. The quenching speed limit elevates with increasing ammonia molar fraction, attributed to the reduced fuel performance. Significantly, the magnetic field broadens the flammable fraction of ammonia, suggesting an effective stabilization strategy. This research underscores the transformative potential of magnetic fields in optimizing flame properties and the energy efficiency of micro-combustion systems powered by ammonia.

On the hazards of proton exchange membrane (PEM) water electrolysis systems using system theoretic process analysis (STPA)

Green hydrogen energy is environmentally sustainable and critical to achieving a carbon-neutral society. Among several water electrolysis technologies, the proton exchange membrane water electrolysis (PEMWE) system, when integrated with renewable energy sources (RES), is seen as a promising green hydrogen production method. PEMWE is especially preferred for high-pressure operation, which decreases the energy usage and cost associated with hydrogen compression. However, it also poses significant operational risks, such as component reliability under dynamic operation, potential hydrogen leakage due to overpressure or component failure, possible hydrogen-oxygen mixtures in the system, and other unanticipated operational challenges. To fully understand the PEMWE system’s operational risk and facilitate risk management, this study conducts a systematic risk analysis using the System Theoretic Process Analysis (STPA) method, involving component failure, system design, human and organizational factors. Combined with the automated and dynamic nature of the system, salient issues during the dynamic operation of the PEMWE system, such as control reliability, component communication reliability and thermal runaway risk, are identified semi-quantitatively. This research is expected to provide a case for STPA research in the highly automated and socio-technical process industry. The findings are expected to offer valuable insights into the safety and reliability of the PEMWE system, providing engineers with technical guidelines for safer system designs, operations, and risk engineering applications, while delivering systematic strategies for risk management. Consequently, a more reliable PEMWE system could lead to the efficient utilization of fluctuating RES.

Synthesis of Ni and Mg MOF-derived carbons for potential hydrogen storage applications

The synthesis of a Ni-trimesic acid (Ni-BTC) metal–organic framework (MOF) under ambient conditions followed by pyrolysis yields a porous MOF-derived carbon (MDC) doped with elemental Ni, appropriate for hydrogen storage applications. The same methods cannot be used for the synthesis of Mg-BTC MOF and its MDC as the reactivity of Mg towards BTC is not sufficient to prevent competing reactions, and Mg is oxidized to MgO during pyrolysis, preventing hydrogen storage via the formation of MgH2.

The Influence of Hydrogen on Structural and Magnetic Transformations in RMn2Hx Hydrides with Laves Phase C15 and C14 Structures—A Review

Laves phases crystallize in simple structures and are very common intermetallic phases that can form from combinations of elements throughout the periodic table, giving a huge number of known examples. A special feature of AB2 or AB5 phases is the ability to absorb hydrogen. This study attempts to collect, systematize and summarize the knowledge about RMn2Hx (R: Tb, Gd, Ho, Dy, Er, Sm, Nd and Y) hydrides available in the literature that is mainly related to structural and magnetic transformations. Due to the enormous wealth of data, the analysis focused on hydrides with x < 4.5 H/f.u., i.e., hydrides obtained at relatively low pressure (less than a few bars). The hydrides obtained in this way can be treated as potential hydrogen stores, which undoubtedly accounts for their current attractiveness.

Crystal Structure, Hirshfeld Surface Analysis, and Biological Activities of Schiff-Base Derivatives of 4-Aminoantipyrine.

Eight Schiff bases, synthesized by the reaction of 4-aminoantipyrine with different cinnamaldehydes, were studied in the solid state by using vibrational spectroscopy (IR) and X-ray diffraction techniques. The analysis was extended to the solution phase through ultraviolet-vis, fluorescence spectroscopy, and cyclic voltammetry. Finally, the crystal structures of four compounds (3b, 3d, 3g, and 3h) were determined and studied. In addition to the experimental study, theoretical calculations using the semiempirical method PM6/ZDO were performed to understand better the compound's molecular properties, UV-vis, and infrared spectra. The primary difference is the angular conformation of the terminal phenyl rings around the corresponding linking C-N and C-C σ-bonds. Furthermore, as a result of extended bonding, the > C=N- azomethine group-containing Cpyr-N=(CH)-(CR)=(CH)-Cbz chain (with R=H for 3b, 3d, and 3h, and R=CH3 for 3g) is planar, nearly coplanar, with the mean plane of the pyrazole ring. Hirshfeld surface (HS) analysis was used to investigate the crystal packing and intermolecular interactions, which revealed that intermolecular C-H···O and C-H···N hydrogen bonds, π···π stacking, and C-H···π and C=O···π interactions stabilize the compounds. The energy contributions to the lattice energies of potential hydrogen bonds were primarily dispersive and repulsive. All derivatives were tested in vitro on LPS-stimulated mouse macrophages to assess their ability to suppress the LPS-induced inflammatory responses. Only a slight reduction in the level of NO production was found in activated macrophages treated with 3h. Additionally, the derivatives were tested for antimicrobial activity against several clinical bacteria and fungi strains, including three biofilm-forming microorganisms. Nevertheless, only Schiff base 3f showed interesting antibacterial activities with minimum inhibitory concentration (MIC) values as low as 15.6 μM against Enterobacter gergoviae. On the other hand, Schiff base 3f and, to a lesser extent, 3b and 3h showed antifungal activity against clinical isolates of Candida. The lowest MIC value was for 3f against Candida albicans (15.6 μM). It is interesting to note that the same Schiff bases exhibit the highest activity in both biological evaluations.

Impact of nano-scale cavities on hydrogen storage and retention in yttrium hydride

In situ synchrotron high-energy x-ray diffraction experiments and detailed transmission electron microscopy (TEM) characterization were conducted on as-fabricated and neutron-irradiated yttrium hydrides. The high-resolution synchrotron x-ray diffraction revealed minor α yttrium and major δ yttrium hydride phases in all specimens. Specimens were subject to heat treatments (heating-cooling cycles), and the intensity of α yttrium partially and completely disappeared in as-fabricated and neutron-irradiated specimens, respectively. The disappearance of α yttrium was unforeseen because hydrogen was expected to leave δ phase, causing an increase in α yttrium diffraction peak intensity. This observation indicated a surplus of hydrogen in the specimens where it was odd for hydride-forming early transition metal elements. The subsequent through-focus TEM characterization discovered nanometric cavities in both as-fabricated and neutron-irradiated yttrium hydride specimens for the first time. Two types of cavities were identified as fabrication-caused and irradiation-induced. The fabrication-caused cavities were associated with regions having linear deformation features, interfaces, and inclusions. The irradiation-induced cavities were observed as being formed isolated in the yttrium hydride phase. The presence of such nanometric cavities was considered as potential hydrogen storage pockets where the overall hydrogen storing capacity of yttrium hydride would be enhanced.

The role of transition metal doping in enhancing hydrogen storage capacity in porous carbon materials

Porous carbon materials with high specific surface area are potential hydrogen storage materials. However, due to the weak van der Waals forces between the material and H2, hydrogen can generally be stored only at a cryogenic temperature under high hydrogen pressure. To solve this problem, in this work, ZIF-8-derived porous carbon material (PCM) modified with transition metals (PCM-TMs, TM: Mn, Fe, Ni) was prepared to investigate the role of TM doping. The developed PCM-TMs have a high specific surface area (up to 1363 m2/g) and pore volume (up to 0.77 cm3/g). Experimental results show that PCM-TMs exhibit higher hydrogen storage capacity, usable capacity, and hydrogen uptake capacity per specific surface area compared to PCM. In addition, PCM-TMs have a higher isosteric heat of adsorption (Qst) than PCM, which suggests that TM doping enhances the interaction between H2 and carbon materials. Theoretical calculations further indicate that this interaction is a nearly weak chemisorption force (∼9.32 kJ/mol). Notably, Mn-doped porous carbon material (PCM-Mn) exhibits a hydrogen storage capacity of ∼3.45 wt% (20.44 g/L) at 77 K under 35 bar-H2. Even at 253 K under 50 bar-H2, the capacity can reach ∼1.41 wt% (8.34 g/L). The hydrogen uptake capacity per specific surface area for PCM-Mn reaches 1.03 × 10-3 wt% / m2·g-1 at 253 K under 50 bar-H2, which is 1.5 times larger than that of PCM. Under proper operating conditions, such as loading at 77 K and 35 bar-H2, and discharging at 253 K and 2 bar-H2, PCM-Mn can achieve a usable capacity of at least 19.30 g/L. The hydrogenation kinetics curves reveal that PCM-Mn can store 1.39 wt%-H2 (8.25 g/L) under 12 MPa H2 at 298 K, while it is only 0.88 wt% (5.53 g/L) for PCM at the same condition. This work provides valuable insight into improving the hydrogen storage performance of hydrogen storage materials of physisorption.

Prospects for hydrogen fuel cell vehicles to decarbonize road transport

This paper explores the role of hydrogen fuel cell vehicles (HFCVs) in helping to meet global climate goals of limiting long-term greenhouse gas (GHG) emissions to 1.5 °C. Employing the GREET Model and data from the International Energy Agency (IEA), the study comprehensively compares the full fuel-cycle emission profiles of HFCVs and battery electric vehicles (BEVs). The paper conducts an in-depth examination of the interplay between the carbon intensity of the electric grid and the resulting GHG emissions within the context of refueling HFCV vehicles via electrolyzers, and the analysis draws a comparison to BEVs charged using the same electric grid. The study finds that while emissions for BEVs increase, emissions for HFCVs are significantly larger when HFCVs are refueled from retail outlets producing hydrogen via electrolysis from grid electricity—a finding that was not previously reached in the current literature. The research underscores that countries operating electric grids characterized by high GHG emissions or lacking robust pathways to emission reduction would face suboptimal outcomes by adopting HFCVs powered by hydrogen sourced from distributed grid electricity generation. The gCO2e/mi for BEVs and HFCVs are also calculated when the electricity is produced from renewable energy resources. When electricity is derived from renewable energy sources, it becomes evident that the gCO2e/mi for both HFCVs and BEVs converge towards ‘zero’. The emission metric of gCO2e/mile for a HFCV refueled with the hydrogen produced from natural gas via steam methane reforming (SMR) without carbon capture utilization and storage (CCUS), stands at 105 gCO2e/mile, whereas in the absence of CCUS, it escalates notably to 247 gCO2e/mile, an approximate 150% increase in stark contrast to CCUS inclusion. This quantitative portrayal serves to underscore the substantial potential for curtailing carbon footprints achievable through the integration of CCUS, thereby amplifying its significance within the realm of hydrogen-based transportation and the broader purview of climate change mitigation endeavors. In order to provide a comprehensive perspective, the study delves into the examination of hydrogen production pathways and associated costs for the years 2021, 2030, and 2050. The forecasted supply costs are elucidated, particularly in relation to the potential hydrogen supply originating from variable renewable energy (solar PV and wind) sources and from CCUS-equipped hydrogen production facilities (considering the project pipeline of projects upto 2030). These factors are of substantial importance in shaping the hydrogen supply landscape and subsequently influencing the adoption of HFCVs in the market. The study also examines the cost implications of hydrogen delivery for varying transportation distances (for 2030), acknowledging their important role in the broader context. The challenges posed by the integration of variable renewable energy sources are also addressed, along with the imperative for effective energy storage solutions. This discourse unfolds within the overarching framework of the energy transition, prominently characterized by the ascendancy of solar PV and wind energy. The intricate interplay of these aspects assumes a critical role in shaping the trajectory of future hydrogen supply dynamics over the medium and long term.

A methodological framework for geospatial modelling of hydrogen demand in cities

Urban energy system planning is vital for cities shifting towards a more sustainable and integrated energy system. Hydrogen is considered one of the most promising solutions in future energy systems. Previous work on hydrogen energy systems predominantly analysed hydrogen models on a national level or only parts of the mobility sector. This indicates a research gap for geospatial models that include multiple sectors in which hydrogen can be used. These models can be used to support decision-making processes around the hydrogen economy in cities. This study presents a holistic model addressing the geospatial modelling of hydrogen demand in urban areas. It proposes a method that integrates a variety of open source data, including geodata, earth observation data and energy data to estimate hydrogen demand top down for the industrial feedstock (steel, ammonia, organic chemistry), process heating, and mobility (buses, trucks, trains, airplanes, ships) sectors. The proposed method can also be extended to different sectors. The method is validated by modelling the hydrogen demand in all German cities and benchmarking it with national studies. This study’s results are within the same range as the results of national studies. For this paper, the method is applied for two case studies in Freiburg im Breisgau and Frankfurt am Main. Applying this method in urban areas shows potential hydrogen demand hotspots in these areas. The model’s results help policymakers and industry stakeholders make informed decisions about the development of hydrogen infrastructure and facilitate the adoption of hydrogen as a low-carbon energy carrier. Future research could explore the temporal aspects of hydrogen demand and the spatial influence of hydrogen demand on future hydrogen production facilities such as electrolysers.

Site and capacity selection for on-site production facilities in a nationwide hydrogen supply chain deployment plan

The Republic of Korea intends to establish a nationwide hydrogen supply chain (HSC) infrastructure to promote the adoption of hydrogen fuel cell vehicles. As the hydrogen demand for mobility may be higher than the estimated production capacity of existing facilities, additional on-site hydrogen refueling stations (HRSs) are required. To address infrastructure deployment problems, a two-stage (demand and supply stages) optimization approach is proposed based on mixed-integer linear programming models. The maximal covering location and p-median models at the demand stage determine the location and chargers of the HRSs and the demand allocation to the stations. At the supply stage, the supply model determines the installation of additional on-site production facilities for the deployed HRSs and the supply allocation to the stations by minimizing the installation and transportation costs. We estimated high-resolution demand data using public sources and utilized investigated supply data from reputable institutions representing the hydrogen economy in the Republic of Korea. The proposed approach provides realistic HSC infrastructure deployment plans, satisfying over 90% of the hydrogen demand in the years 2025 and 2030. Additionally, a sensitivity analysis indicated the effects of various parameters on the deployment plan, including the demand coverage and the need for additional on-site HRSs to address potential hydrogen supply shortages.

Practical mutual transformation of azobenzene and hydrazobenzene using porous BN supported Cu nanoparticles as a redox catalyst

Azobenzene and hydrazobenzene compounds are essential intermediates for synthesizing pharmaceuticals and dyes. Meanwhile, the hydrazobenzene/azobenzene couple is a potential hydrogen storage system when both the dehydrogenation of hydrazobenzene and the hydrogenation of azobenzenes can be achieved under mild reaction conditions. In this work, we report an entirely mutual transformation of azobenzene and hydrazobenzene under very mild conditions using porous BN supported Cu nanoparticles (Cu/PBN) as the catalyst for the first time. Direct oxidative dehydrogenation reaction proceeded in the open air with the removal of molecular hydrogen as the by-product and a wide range of hydrazobenzenes readily undergoes dehydrogenation, resulting in an excellent yield of the corresponding azobenzene.

Hydrogen-Driven Microbial Redox Reactions in Deep Geosystems

In the subsurface, biotic and abiotic processes can generate and consume hydrogen. Hydrogen has a low reduction potential and is thus a highly energetic electron donor when involved in sulfate, carbon dioxide or ferric iron reduction. Although known as important drivers for the deep biosphere, the contributions of different processes to hydrogen turnover in different geosystems still are not well understood. In context with the ongoing transformation to renewable energy resources, underground H2 storage (UHS) in deep porous or salt cavern systems came into focus. In situ microbial and geochemical reactions that consume H2 are highly relevant topics in deep biosphere research, and also are still a major uncertainty during UHS. Consequently, we studied the potential microbial hydrogen oxidation rates – combined with the possible production of metabolic products like H2S, acetic acid or CH4 - in formation fluids from natural gas fields and salt caverns, thereby considering the importance of in situ pressure and temperature conditions, fluid chemistry and mineral composition. In addition, more defined experiments were conducted with selected pure cultures representing important metabolic groups of deep biosphere microorganisms. Several original formation fluids showed immediate H2 consumption. Microorganisms oxidized hydrogen at relevant in situ pressure conditions (up to 100 bar) and tolerated dynamically changing pressure and temperature conditions. The microbial hydrogen oxidation rate was strongly dependent on H2 partial pressures and the availability of e.g., sulfate as a terminal electron acceptor. High-throughput sequencing of 16S rRNA gene amplicons indicated hydrogen oxidation by sulfate reducing bacteria to be the presumed process in the studied porous rock reservoir fluids. In addition, hydrogen turnover by methanogenic and acetogenic as well as iron-reducing microorganisms was investigated. Also, the importance of biotic reactions in relation to abiotic hydrogen turnover processes at mineral surfaces will be discussed.