Search Results (857)

Hydrogen production is increasingly vital for global decarbonization but remains a water- and energy-intensive process, especially in arid regions. Despite growing attention to its climate benefits, limited research has addressed the environmental impacts of water sourcing. This study employs a life cycle assessment (LCA) approach to evaluate three water supply strategies for hydrogen production: (1) seawater desalination without brine treatment (BT), (2) desalination with partial BT, and (3) freshwater purification. Scenarios are modeled for the United Arab Emirates (UAE), Australia, and Spain, representing diverse electricity mixes and water stress conditions. Both electrolysis and steam methane reforming (SMR) are evaluated as hydrogen production methods. Results show that desalination scenarios contribute substantially to human health and ecosystem impacts due to high energy use and brine discharge. Although partial BT aims to reduce direct marine discharge impacts, its substantial energy demand can offset these benefits by increasing other environmental burdens, such as marine eutrophication, especially in regions reliant on carbon-intensive electricity grids. Freshwater scenarios offer lower environmental impact overall but raise water availability concerns. Across all regions, feedwater for SMR shows nearly 50% lower impacts than for electrolysis. This study focuses solely on the environmental impacts associated with water sourcing and treatment for hydrogen production, excluding the downstream impacts of the hydrogen generation process itself. This study highlights the trade-offs between water sourcing, brine treatment, and freshwater purification for hydrogen production, offering insights for optimizing sustainable hydrogen systems in water-stressed regions. Full article

This study investigates the effects of samarium (Sm) promotion on the catalytic activity of 5 weight percent Ni catalysts for partial oxidation of methane (POM)-based hydrogen production supported on a Si-Al mixed oxide (10SiO₂+90Al₂O₃) system. Several 5% Ni-based catalysts supported on silica–alumina was used to test the POM at 600 °C. Sm additions ranged from 0 to 2 wt.%. Impregnation was used to create these catalysts, which were then calcined at 500 °C and examined using BET, H₂-TPR, XRD, FTIR, TEM, Raman spectroscopy, and TGA methods. Methane conversion (57.85%) and hydrogen yield (56.89%) were greatly increased with an ideal Sm loading of 1 wt.%, indicating increased catalytic activity and stability. According to catalytic tests, 1 wt.% Sm produced high CH₄ conversion and H₂ production, as well as enhanced stability and resistance to carbon deposition. Nitrogen physisorption demonstrated a progressive decrease in pore volume and surface area with the addition of Sm, while maintaining mesoporosity. At moderate Sm loadings, H₂-TPR and XRD analyses showed changes in crystallinity and increased NiO reducibility. Sm incorporation into the support and its impact on the ordering of carbon species were indicated by FTIR and Raman spectra. The optimal conditions to maximize H₂ yield were successfully identified through optimization of the best catalyst, and there was good agreement between the theoretical predictions (87.563%) and actual results (88.39%). This displays how successfully the optimization approach achieves the intended outcome. Overall, this study demonstrates that the performance and durability of Ni-based catalysts for generating syngas through POM are greatly enhanced by the addition of a moderate amount of Sm, particularly 1 wt.%. Full article

The mechanism by which voltage-gated ion channels open and close has been the subject of intensive investigation for decades. For a large class of potassium channels and related sodium channels, the consensus has been that the gating current preceding the main ionic current is a large movement of positively charged segments of protein from voltage-sensing domains that are mechanically connected to the gate through linker sections of the protein, thus opening and closing the gate. We have pointed out that this mechanism is based on evidence that has alternate interpretations in which protons move. Very little literature considers the role of water and protons in gating, although water must be present, and there is evidence that protons can move in related channels. It is known that water has properties in confined spaces and at the surface of proteins different from those in bulk water. In addition, there is the possibility of quantum properties that are associated with mobile protons and the hydrogen bonds that must be present in the pore; these are likely to be of major importance in gating. In this review, we consider the evidence that indicates a central role for water and the mobility of protons, as well as alternate ways to interpret the evidence of the standard model in which a segment of protein moves. We discuss evidence that includes the importance of quantum effects and hydrogen bonding in confined spaces. K⁺ must be partially dehydrated as it passes the gate, and a possible mechanism for this is considered; added protons could prevent this mechanism from operating, thus closing the channel. The implications of certain mutations have been unclear, and we offer consistent interpretations for some that are of particular interest. Evidence for proton transport in response to voltage change includes a similarity in sequence to the H_v1 channel; this appears to be conserved in a number of K⁺ channels. We also consider evidence for a switch in -OH side chain orientation in certain key serines and threonines. Full article

To achieve energy transition, hydrogen and carboxylic acids have attracted much attention due to their cleanliness and renewability. Anaerobic fermentation technology is an effective combination of waste biomass resource utilization and renewable energy development. Therefore, the utilization of anaerobic fermentation technology is expected to achieve efficient co-production of hydrogen and carboxylic acids. However, this process is fundamentally affected by gas–liquid mass transfer kinetics, bubble behaviors, and system partial pressure. Moreover, the related studies are few and unfocused, and no systematic research has been developed yet. This review systematically summarizes and discusses the basic mathematical models used for gas–liquid mass transfer kinetics, the relationship between gas solubility and mass transfer, and the liquid-phase product composition. The review analyzes the roles of the headspace gas composition and partial pressure of the reaction system in regulating co-production. Additionally, we discuss strategies to optimize the metabolic pathways by modulating the gas composition and partial pressure. Finally, the feasibility of and prospects for the realization of hydrogen and carboxylic acid co-production in anaerobic fermentation systems are outlined. By exploring information related to gas mass transfer and system pressure, this review will surely provide an important reference for promoting cleaner production of sustainable energy. Full article

Hydrogen is a promising zero-carbon fuel for internal combustion engines; however, the geometric optimization of injectors for low-pressure direct-injection (LPDI) systems under lean-burn conditions remains underexplored. This study presents a high-fidelity optimization framework that couples a validated computational fluid dynamics (CFD) combustion model with a surrogate-assisted multi-objective genetic algorithm (MOGA). The CFD model was validated using particle image velocimetry (PIV) data from non-reacting flow experiments conducted in an optically accessible research engine developed by Sandia National Laboratories, ensuring accurate prediction of in-cylinder flow structures. The optimization focused on two critical geometric parameters: injector hole count and injection angle. Partial indicated mean effective pressure (pIMEP) and in-cylinder NO_x emissions were selected as conflicting objectives to balance performance and emissions. Adaptive mesh refinement (AMR) was employed to resolve transient in-cylinder flow and combustion dynamics with high spatial accuracy. Among 22 evaluated configurations including both capped and uncapped designs, the injector featuring three holes at a 15.24° injection angle outperformed the baseline, delivering improved mixture uniformity, reduced knock tendency, and lower NO_x emissions. These results demonstrate the potential of geometry-based optimization for advancing hydrogen-fueled LPDI engines toward cleaner and more efficient combustion strategies. Full article

This work addresses for the first time the effect of anode serpentine channel depth on Methanol Electrolysis Cells (MECs) and Direct Methanol Fuel Cells (DMFCs) for improving performance of both devices. Anode plates with serpentine flow fields of 0.5 mm, 1.0 mm and 1.5 mm depths are designed and tested in single-cells to compare their behaviour. Performance was evaluated through methanol crossover, polarization and power density curves. Results suggest shallower channels enhance mass transfer efficiency reducing MEC energy consumption for hydrogen production at 40 mA∙cm⁻² by 4.2%, but increasing methanol crossover by 30.3%. The findings of this study indicate 1.0 mm is the best depth among those studied for a MEC with 16 cm² of active area, while 0.5 mm is the best for a DMFC with the same area with an increase in peak power density of 14.2%. The difference in results for both devices is attributed to higher CO₂ production in the MEC due to its higher current density operation. This increased CO₂ production alters anode two-phase flow, partially hindering the methanol oxidation reaction with shallower channels. These findings underscore the critical role of channel depth in the efficiency of both MEC and DMFC single-cells. Full article

Underground hydrogen storage (UHS) in carbonate and siliceous formations presents a promising solution for managing intermittent renewable energy. However, experimental data on hydrogen–rock interactions under representative subsurface conditions remain limited. This study systematically investigates mineralogical and petrophysical alterations in dolomite, calcite-rich limestone, and quartz-dominant siliceous cores subjected to high-pressure hydrogen (100 bar, 70 °C, 100 days). Distinct from prior research focused on diffraction peak shifts, our analysis prioritizes quantitative changes in mineral concentration (%) as a direct metric of reactivity and structural integrity, offering more robust insights into long-term storage viability. Hydrogen exposure induced significant dolomite dissolution, evidenced by reduced crystalline content (from 12.20% to 10.53%) and accessory phase loss, indicative of partial decarbonation and ankerite-like formation via cation exchange. Conversely, limestone exhibited more pronounced carbonate reduction (vaterite from 6.05% to 4.82% and calcite from 2.35% to 0%), signaling high reactivity, mineral instability, and potential pore clogging from secondary precipitation. In contrast, quartz-rich cores demonstrated exceptional chemical inertness, maintaining consistent mineral concentrations. Furthermore, Brunauer–Emmett–Teller (BET) surface area and Barrett–Joyner–Halenda (BJH) pore distribution analyses revealed enhanced porosity and permeability in dolomite (pore volume increased >10×), while calcite showed declining properties and quartz showed negligible changes. SEM-EDS supported these trends, detailing Fe migration and textural evolution in dolomite, microfissuring in calcite, and structural preservation in quartz. This research establishes a unique experimental framework for understanding hydrogen–rock interactions under reservoir-relevant conditions. It provides crucial insights into mineralogical compatibility and structural resilience for UHS, identifying dolomite as a highly promising host and highlighting calcitic rocks’ limitations for long-term hydrogen containment. Full article

Prion diseases such as chronic wasting disease involve the conformational conversion of the cellular prion protein (PrP^C) into its misfolded, β-rich isoform (PrP^Sc). While chemical denaturants such as guanidine hydrochloride (GdnHCl) and urea are commonly used to study this process in vitro, their distinct molecular effects on native and misfolded PrP conformers remain incompletely understood. In this study, we employed 500 ns all-atom molecular dynamics simulations and essential collective dynamics analysis to investigate the differential effects of GdnHCl and urea on a composite PrP^C/PrP^Sc system, where white-tailed deer PrP^C interfaces with a corresponding PrP^Sc conformer. GdnHCl was found to preserve interfacial alignment and enhance β-sheet retention in PrP^Sc, while urea promoted partial β-strand dissolution and interfacial destabilization. Both denaturants formed transient contacts with PrP, but urea displaced water hydrogen bonds more extensively. Remarkably, we also observed long-range dynamical coupling across the PrP^C/PrP^Sc interface and between transiently bound solutes and distal protein regions. These findings highlight distinct, denaturant-specific mechanisms of protein destabilization and suggest that localized interactions may propagate non-locally via mechanical or steric pathways. Our results provide molecular-scale insights relevant to prion conversion mechanisms and inform experimental strategies using GdnHCl and urea to modulate misfolding processes in vitro. Full article

Biochar has demonstrated effectiveness in environmental remediation. However, the physicochemical properties of biochar change with natural aging, which potentially impacts its efficacy. This study was designed to evaluate the effects of aged biochar (at 1% and 5% rates) on the growth of Chinese cabbage, greenhouse gas emission, and Cd remediation in soils. Canada goldenrod (Solidago canadensis L.) feedstock biochar was subjected to three artificial aging processes (freeze–thaw cycle, dry–wet cycle, and hydrogen peroxide oxidation) to prepare aged biochar. Results showed that aging significantly altered properties and structure of biochar. Biochar addition had no effect on CH₄ emissions, but it decreased cumulative N₂O emission (all treatments) and increased cumulative CO₂ emission (only the pristine biochar at 5% application rate). Aged biochar showed no effect on microbial life strategy and Shannon index. However, PB-5% application shifted the life history strategies of A-strategists (resource acquisition microbe) towards Y-strategists (high-yield microbe) such as Proteobacteria, Gemmatimonadota, Bacteroidota, Firmicutes and Actinobacteriota, which partially attributed to the enhanced soil CO₂ emission. Aged biochar reduced plant uptake Cd and soil available Cd concentrations by up to 36.6% and 34.0%, respectively, ascribing to improved soil physicochemical properties and functional bacterial abundance. Full article

Ammonia is increasingly recognised as a promising carbon-free fuel and hydrogen carrier due to its high hydrogen content, ease of liquefaction, and existing global infrastructure. However, its direct utilisation in combustion systems poses significant challenges, including low flame speed, high ignition temperature, and the formation of nitrogen oxides (NO_X). This review explores catalytic ammonia cracking as a viable method to enhance combustion through in situ hydrogen production. It evaluates traditional catalytic burner designs originally developed for hydrocarbon fuels and assesses their adaptability for ammonia-based applications. Special attention is given to ruthenium- and nickel-based catalysts supported on various oxides and nanostructured materials, evaluating their ammonia conversion efficiency, resistance to sintering, and thermal stability. The impact of the main operational parameters, including reaction temperature and gas hourly space velocity (GHSV), is also discussed. Strategies for combining partial ammonia cracking with stable combustion are studied, with practical issues such as catalyst degradation, NO_X regulation, and system scalability. The analysis highlights recent advancements in structural catalyst support, which have potential for industrial-scale application. This review aims to provide future development of low-emission, high-efficiency catalytic burner systems and advance ammonia’s role in next-generation hydrogen energy technologies. Full article

The removal of partially hydrogenated fats, as well as the substitution of saturated fats with healthier alternatives, has become increasingly common due to their well-established association with adverse health effects. As a result, the demand for alternative formulations in the food industry has driven the development of a promising emerging technology: oleogels. Oleogels are a semi-solid material made by trapping liquid oil within a three-dimensional network formed by structuring agents. Within this context, this study aimed to develop and characterize margarines prepared with oleogels formulated from extra virgin olive oil, coconut oil, starch, and beeswax at varying concentrations. The proposed oleogel-based formulations exhibited a high melting temperature range and lower enthalpy. Although lipid oxidation levels differed between the commercial and oleogel-based margarines, they remained within acceptable limits. A significant difference in color was observed, with the oleogel formulations imparting a slight greenish hue compared to the commercial margarine. In terms of microstructure, the commercial margarine presented smaller and more uniformly distributed water droplets. Oleogel-based margarines demonstrated technological feasibility. Considering consumers’ growing interest in food innovation and health-conscious products, olive oil-based oleogel margarines represent a promising alternative, particularly due to the nutritional benefits associated with olive oil. Full article

In this study, we address the need for sustainable and scalable synthesis routes for hydrogen storage materials by developing a FeTi alloy in which vanadium (V) partially substitutes for titanium (Ti). The alloy was synthesized using mechanical alloying, compaction, and post-annealing, employing industrial-grade Fe and Ti powders and an alternative to pure vanadium, i.e., ferrovanadium (Fe–V). X-ray diffraction (XRD) analysis of the mechanically alloyed mixture revealed the partial formation of a Fe(V) solid solution, along with residual Ti. Subsequent compaction and annealing at 1000 °C led to the formation of the FeTi(V) phase, accompanied by two minor secondary phases, Fe₂Ti and Fe₂Ti₄O. A maximum phase yield of 90% for FeTi was achieved after 48 h of annealing. The novelty of this work lies in the demonstration of a sustainable and economical synthesis approach for V-substituted FeTi alloys using industrial-grade raw materials, offering a potential reduction in the carbon footprint compared with conventional melting techniques. Full article

The adsorption of the drug gemcitabine on nucleobases was investigated using a dispersion-corrected density functional theory (DFT) study. The planar structure of complexes is more stable than those with stacked and buckle-angled configurations. The complexes were found to possess at least two intermolecular hydrogen bonds. The binding energy and interaction energy are both negative, with the highest values observed for the gemcitabine–guanine and the lowest in the gemcitabine–thymine complex. The complex formation was found to be an enthalpy-driven process. Pyrimidine nucleobases have a lower enthalpy of formation than purine nucleobases. The computed HOMA and NICS values on the gemcitabine–nucleobase complexes show a substantial increase compared to the pristine nucleobases. An MESP analysis of the complexes shows a directional interaction and electron density shift between the gemcitabine and the nucleobases. A QTAIM analysis indicates that the intermolecular hydrogen bonds have a partial covalent character. The computed bond energy demonstrates that intermolecular NH⋅⋅⋅N bonds are more potent than other bonds. An energy decomposition analysis using the DLPNO−CCSD(T) method indicates that the complexes exhibit a substantial electrostatic attraction, and dispersion contributes the least towards the system stability. The intermolecular bonds are stronger than the intramolecular bonds in the drug–nucleobase complexes. The strength of intramolecular bonds is determined by the deformation of the gemcitabine ring during the complex formation. Full article

In this study, a novel anode-supported solid oxide fuel cell (SOFC) comprising a Bi₂O₃-doped NiO-ScSZ anode and an ScSZ electrolyte was successfully fabricated via a low-temperature co-sintering process at 1300 °C. The incorporation of 3 wt% Bi₂O₃ effectively promoted the sintering of both the anode support and electrolyte layer, resulting in a dense, gas-tight electrolyte and a mechanically robust porous anode support. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the formation of phase-pure, highly crystalline ScSZ with an optimized microstructure. Electrochemical performance measurements demonstrated that the fabricated cells achieved excellent power density, reaching a peak value of 0.861 W cm⁻² at 800 °C under humidified hydrogen fuel conditions. The cells maintained stable performance under dry methane operation, with a maximum power density of 0.624 W cm⁻² at 800 °C, indicating resistance to carbon deposition. Gas chromatographic analyses further revealed that the Bi₂O₃-doped NiO-ScSZ anode facilitated earlier and more stable electrochemical oxidation of methane-derived species compared with the conventional NiO-YSZ system, even under conditions of an elevated methane partial pressure. These findings demonstrate that Bi₂O₃ co-doping, combined with low-temperature co-sintering, provides an effective approach for fabricating high-performance intermediate-temperature SOFCs with enhanced structural integrity and electrochemical stability. The developed methodology presents a promising pathway toward achieving cost-effective and durable SOFC technologies. Full article

The electrochemical oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) coupled with water electrolysis for green hydrogen production is a promising strategy to address energy crises and environmental pollution. Despite the suitable adsorption energy for HMF due to their partially filled d-band electronic structures, Ni- or Co-based oxides/hydroxides still face challenges in insufficient activity and stability. In this study, a porous heterogeneous nickel cobalt oxide/hydroxide growth on nickel foam (NF), which is defined as NF@NiCo-H/O, was developed via immersion in concentrated alkali solution. Compared with the single-component NiCo oxides, the NF@NiCo-H/O catalyst exhibits a lower application potential of only 1.317 V, 1.395 V, and 1.443 V to achieve current densities of 20, 50, and 100 mA cm⁻², respectively, in an alkaline solution containing HMF. Additionally, it demonstrates rapid reaction kinetics with a Tafel slope of 27.6 mV dec⁻¹ and excellent cycling stability. Importantly, the presence of more high-valent Ni³⁺-O species on the catalyst surface contributes to its exceptional selectivity for 2,5-furandicarboxylic acid (86.7%), Faradaic efficiency (93.1%), and conversion rate (94.4%). This catalyst provides some theoretical guidance for the development of biomass electrooxidation catalysts for sustainable energy and chemical production. Full article