Energy & Fuels最新文献

The development of efficient electrocatalysts for overallwatersplitting and metal–air batteries remains challenging due tothe need to simultaneously optimize active-site stability, intermediateadsorption energetics, and catalytic performance across multiple electrochemicalreactions. In this study, density functional theory (DFT) calculationsare performed to investigate homonuclear dual-transition-metal catalystssupported on a Lindqvist-type polyoxotungstate (POT) cluster. A seriesof 23 TM₂/POT systems is systematically evaluated to establishstructure–property-activity relationships linking dual-metalcoordination, catalyst stability, electronic structure, and reactionenergetics toward the hydrogen evolution reaction (HER), oxygen evolutionreaction (OER), and oxygen reduction reaction (ORR). V₂/POT exhibits near-thermoneutral hydrogen adsorption (ΔG_H* = 0.05 eV), indicating favorable HER thermodynamics.For oxygen electrocatalysis, Au₂/POT and Ni₂/POT show promising bifunctional OER and ORR performance, with calculatedoverpotentials of 0.55 and 0.59 V for OER and 0.56 and 0.65 V forORR, respectively, together with favorable formation energies of −0.42eV (Au₂/POT) and −1.41 eV (Ni₂/POT) anddissolution potentials of 1.64 V (Au₂/POT) and 0.44 V (Ni₂/POT). The activity trends are interpreted through d-band center analysis, charge redistribution, and projecteddensity of states (PDOS). Overall, dual-metal incorporation withinthe POT framework modulates local coordination and charge redistribution,thereby tuning adsorption energetics and establishing structure–property-activityrelationships for the rational design of electrocatalysts for overallwater splitting and metal–air batteries.

Electron transport, electrolyte accessibility, and structuralstabilityare three key factors that influence hydrogen evolution reaction (HER)activity and catalyst durability. In this study, a coal gasificationslag waste-derived carbon–silica (C@SiO₂) supportwas used to prepare Ni-based HER electrocatalysts. The catalyst (rNi/C@SiO₂) was prepared through chemical reduction of Ni impregnatedin C@SiO₂, followed by hydrothermal treatment. In 1.0 MKOH, rNi/C@SiO₂ achieved an overpotential of 240 mV at10 mA cm^–2, a Tafel slope of 180.64 mV dec^–1, a charge-transfer resistance of 32.37 Ω, an electrochemicallyactive surface area of 609.75 cm², stability for 15 h at50 mA cm^–2, and only slight degradation after 1000cycles. The advantages of rNi/C@SiO₂ are attributed tothe slit-like mesoporous structure of C@SiO₂ and dominantfcc Ni(111). The hydrophilic SiO₂ and highly mesoporousstructure of C@SiO₂ enhance KOH–H₂O infiltrationin rNi/C@SiO₂. The fcc Ni(111) contributes to the reductionof charge transfer resistance, thus enhancing HER. This study hasshown a sustainable approach to use industrial waste as a catalystsupport for hydrogen production.

Clathrates are crystallinecompounds with a wide rangeof applications,particularly in the fields of storage of substances of interest (suchas hydrogen) and gas separation. In this work, molecular dynamicssimulations are used to investigate the stability of β-hydroquinone clathrates (HQ clathrates) containing guest moleculessuch as Ar, CH₄, H₂, and CO₂ in apressure range between 100 and 1000 bar. To this end, the isobaric-isenthalpic(NPH) ensemble was used, which allows the equilibriumconditions to be studied without applying artificial temperature control,providing a direct and more realistic view of the thermodynamic responseof the system. Atomistic models based on the OPLS-AA force field areused for this purpose. The results reveal a tendency for the coexistencetemperature to increase with pressure, which is more pronounced forlarger, apolar guests (Ar and CH₄) compared to smaller,polar species (H₂, CO₂). This study representsthe first application of the NPH-based methodologyto organic clathrates, demonstrating its effectiveness in studyingthe limiting thermodynamic conditions associated with phase transitions.The findings presented provide a solid theoretical framework for understandingthe dynamic behavior of HQ clathrates and open up new perspectivesfor their use in the safe and reversible storage of hydrogen.

Reliable monitoring of geomechanical responses is essentialforthe safe and sustainable production of gas hydrate reservoirs. Thisstudy reports the first field-scale application of distributed strainsensing (DSS) during a 10 month extended gas production test on Alaska’sNorth Slope. DSS cables installed in production and monitoring wellscontinuously captured axial and bending strain at high spatial resolution,directly linking depressurization to formation deformation. The observationsrevealed compressive strain within the hydrate-bearing interval andtensile strain in the surrounding layers, consistent with stress redistributionpreviously predicted by geomechanical simulations. After the transitionfrom electric submersible pump (ESP) to jet-pump operation, localizedbending strain became evident, suggesting possible casing–cementdeformation. Interwell measurements further demonstrated strain propagationand physically consistent attenuation away from the production well.Integrated analysis indicated that inward casing–cement deflectionduring depressurization could have a greater contribution to the measuredstrain than reservoir compaction and that plastic strain may havedeveloped in the cement where the DSS cable was embedded. This findingemphasizes the need for integrated validation with numerical simulationsand additional testing to improve the current quantitative assessmentof reservoir deformation, which remains subject to uncertainty. Overall,this study provides the first long-term, field-scale evidence of stressredistribution in hydrate-bearing sediments, establishing DSS as apromising monitoring technology and offering critical insights forreservoir simulation, geomechanical risk assessment, and the futurecommercial deployment of methane hydrate production systems.

Liquid organic hydrogen carriers (LOHCs) represent asafe and cost-effectiveresource for hydrogen storage due to reversible hydrogenation/dehydrogenationcycles. Although scarcely studied, the 1-methylnaphthalene/1-methyldecalin(1-MN/1-MD) pair could be an attractive LOHC due to its physical propertiesand because it can be obtained from waste streams of the carbochemicalindustry. However, 1-MD dehydrogenation is strongly affected by itsstereoisomeric composition, as cis- and trans-isomers exhibit differentreactivities and can undergo concurrent isomerization. In this work,the influence of individual 1-MD stereoisomers on dehydrogenationperformance was systematically investigated using two feeds enrichedin either cis- or trans-isomers. Pd- and Pt-based catalysts supportedon alumina and activated carbon were evaluated, and the effect oftemperature (250–400 °C) was studied over the most activecatalyst, Pt/Al₂O₃. Based on the experimentaldata, we hypothesized that trans-isomers promoted catalyst deactivationand coke formation, whereas cis-isomers enhanced dehydrogenation activity.This effect is also believed to influence the formation of intermediateproducts. Specifically, 1-methyltetralin, which is generated mainlyfrom cis-isomers, readily dehydrogenates to 1-methylnaphthalene (1-MN),whereas 5-methyltetralin, formed preferentially from trans-isomers,appears to promote catalyst deactivation.

As energy consumption globally keepsincreasing, refining betterand more efficient enhanced oil recovery (EOR) methods, especiallythose with surfactants, will be crucial to sustain future energy demand.Such advances will not just increase the economic viability of oilproduction but also contribute to long-term energy resource sustainability.Emulsifiers play a vital role in the oil industry by destabilizingwater-in-oil emulsions, improving the quality of oil and reducingprocessing costs. In this study, polyethylene wax was first modifiedwith maleic anhydride to obtain PE@MA. Then, in order to increasethe hydrophilicity of the PE, a ring-opening reaction was performedon the maleic anhydride rings to prepare PE@MA^–Na⁺. Then, demulsification efficiency of the prepared compoundsin W/O emulsions was studied. Pure maleic anhydride did not possessdemulsifying properties and was not effective in water dehydrationfrom oil. Polyethylene modified with maleic anhydride (PE@MA) showeda lower dehydration efficiency compared to the polyethylene wax modifiedwith maleic anhydride salt (PE@MA^–Na⁺). The optimized salt-modified demulsifier, PE@MA^–Na⁺, possessed good interfacial properties to break theasphalt films at the oil-water interface with improved water dehydration.PE@MA^–Na⁺ displayed a dehydration of≈100% at an exceptionally low dosage of 100 ppm in less than5 min at a relatively low temperature (≤50 °C). The exceptionalperformance of the PE@MA^–Na⁺ can be attributedto its high amphiphilic interfacial properties, which facilitatesinterfacial adsorption, disrupts asphaltene-stabilized layers, andsignificantly reduces the interfacial tension. In summary, the abovefindings demonstrate that the PE@MA^–Na⁺ can be an efficient and promising next-generation demulsifier forthe crude-oil dehydration.

The rapid expansion of flexible, portable, and wearable electronictechnologies has heightened the need for energy-storage systems thatprovide mechanical durability and operational safety. MOFs (MetalOrganic Frameworks) have attracted considerable attention due to theirhighly tunable porous architectures, large accessible surface areas,and abundant redox-active metal centers. In this work, a Ni intercalatedbimetallic CuCo-BDC MOF was synthesized, aiming to exploit multimetalsynergistic effects, enhance redox activity, and improve ion-transportdynamics. Structural and morphological analyses confirm that Ni incorporationpreserves the crystalline integrity and mesoporous, sheet-like architectureof the parent framework. Electrochemical investigations demonstratethat the Ni-CuCo-BDC MOF significantly enhanced charge storage behavior,achieving a high areal capacity of 82.917 μAh cm^–2 at a current density of 1 mA cm^–2 in a three-electrodeconfiguration. The assembled solid-state FES device exhibits a capacityof 13.389 μAh cm^–2, an energy density of 5.356μWh cm^–2, and a power density of 400 μWcm^–2, along with excellent mechanical flexibilityand ∼90.2% capacity retention after 5000 cycles. These outcomeshighlight the potential of the Ni-CuCo-BDC MOF as a promising energystorage candidate for wearable and portable electronics.

The inclusion ofdetailed chemical kinetics in multidimensionalsimulations of reactive flows remains computationally very demanding.Among the techniques used to reduce the cost associated with detailedchemistry, cell agglomeration (CA) has proven particularly effectivein simulations based on the operator-splitting approach, where cellswith similar thermochemical states are grouped and integrated togetherduring the chemical step. In this work, a new methodology for theautomatic selection of clustering variables in CA is proposed basedon principal component analysis (PCA). In the proposed P(CA)² (PCA-based Cell Agglomeration) approach, the clustering is performedin a reduced space defined by the most relevant principal componentsof the thermochemical state. This removes the arbitrariness associatedwith the manual selection of temperature and species mass fractionstypically used as clustering features in conventional CA algorithms.Moreover, the PCA space is dynamically updated during the simulation,allowing the clustering procedure to adapt to the evolving thermochemicalstructure of the reacting flow. The P(CA)² methodologywas assessed on an unsteady laminar coflow diffusion flame using kineticmechanisms of increasing complexity, including a mechanism with 224species and 5939 reactions. The method was also tested on a temporallyevolving turbulent planar jet flame. The results show that P(CA)² provides accurate solutions while achieving significant computationalacceleration, with effective overall speed-ups reaching approximately70–80% of the asymptotic maximum allowed by the nonchemistryfraction of the computational cost. The proposed approach removesthe need for heuristic selection of clustering variables, providessystematic control of the solution accuracy, and can be easily integratedinto existing CFD solvers based on operator splitting. These featuresmake P(CA)² a promising tool for accelerating simulationsof reactive flows involving detailed chemical kinetic mechanisms.

Semitransparent indoor photovoltaics (IPVs) based onlayered perovskitesoffer opportunities for integrated energy harvesting, yet their structuralunderstanding and implementation remain limited. Here, we report thefirst demonstration of semitransparent thin-film photovoltaic operationusing a quasi-2D Dion–Jacobson (DJ) perovskite absorber (n= 5). Owing to the absence of crystallographic information for thisphase, density functional theory (DFT) calculations were employedto establish a structural model, which was used to interpret experimentalobservations. The optimized structure exhibits a layered frameworkwith a slight octahedral tilt and a wide bandgap with nearly directband-edge characteristics. Experimental results reveal that precursorconcentration critically governs crystallization behavior, latticestrain, and film morphology. An optimal condition yields a continuous,low-strain film with favorable semitransparent characteristics andenables corresponding device operation under indoor illumination.These findings highlight the importance of crystallization controlin DJ perovskites and provide a framework for designing semitransparentquasi-2D absorbers for IPV applications.

Theincreasing demand for oil and the need for improvedrecoverymethods have increased interest in nanoparticle–surfactant–polymersystems for enhanced oil recovery (EOR). In this study, zinc oxide(ZnO) and silica (SiO₂) nanoparticles were used with sodiumdodecylbenzenesulfonate (SDBS) and two polymers, polyethylene glycol(PEG) and carboxymethyl cellulose (CMC). The nanofluids were preparedusing high-energy ultrasonication, and their stability, rheologicalbehavior, interfacial tension (IFT), wettability, and oil recoveryperformance were studied. ZnO nanofluids showed better colloidal stabilitythan SiO₂ nanofluids. The nanofluids showed shear-thinningbehavior, and viscosity generally decreased with increasing temperatureand salinity. The effect of NaCl salinity and formation water on therheological behavior was also evaluated. FT-IR analysis indicatedchanges in the hydrocarbon-associated spectral features after oilrecovery. Wettability analysis showed a change in sandstone wettabilityfrom intermediate-wet conditions to strongly water-wet conditions.Core-flooding experiments showed additional oil recoveries of 25.92%,37.24%, 30.64%, and 30.34% OOIP for ZnO–CMC, SiO₂–CMC, ZnO–PEG, and SiO₂–PEG nanofluids,respectively. Among the tested formulations, the SiO₂–CMCsystem showed the highest additional oil recovery of 37.24% OOIP.A preliminary economic evaluation was also performed to compare theestimated preparation costs of the developed formulations. Overall,the results show that ZnO- and SiO₂-based SDBS–polymernanofluids have potential for improving oil recovery through changesin fluid properties and rock wettability.