Energy & Fuels最新文献

Existing numerical methods for stagedammonia combustion incurprohibitively high computational costs, limiting their applicabilityto engineering calculations. To address this limitation, this workdevelops an engineering-oriented, nonadiabatic dynamic adaptive flamelet-generatedmanifold (DA-FGM) method within a Reynolds-averaged Navier–Stokes(RANS) framework to enable computationally efficient analysis of stagedammonia combustion. By incorporating localized heat-loss effects throughenthalpy mapping and validating against experimental and higher-fidelitynumerical results, the framework is applied to investigate oxygen-enrichedammonia swirl combustion under an axially staged configuration. Acrossoxygen enrichment levels of 21%–35%, at a fixed primary equivalenceratio of Φ_pri = 1.2 and global equivalence ratioof Φ_glob = 0.4, oxygen enrichment is found to enhanceoverall flame stabilization and modify multistage combustion behaviorthrough coupled thermo-aerodynamic effects. Thermally, increased oxygenconcentration (X_O2) promotesfuel-rich pyrolysis and accelerates the formation of H₂ intermediates that dominate subsequent stages. Aerodynamically,reduced secondary jet momentum weakens local shear levels and altersthe turbulent strain rate distribution, thereby reshaping flame stabilizationcharacteristics. Under the present protocol with constant power andfixed Φ_glob, increasing X_O2 from 21% to 35% leads to a monotonic reduction in NOemissions while increasing NH₃ and H₂ slip.This behavior arises from a competition between enhanced downstreamthermal DeNOx activity in the core flow, driven by transported NH₃ and elevated temperatures, and incomplete conversion in near-wallregions where heat loss suppresses local reactivity. The results highlightthe critical role of thermal management in sustaining high-efficiencyNH₃ combustion under oxygen-enriched conditions.

The complex ionic environment in high-salinity reservoirscan weakensurfactant adsorption at oil–water interfaces and compromiseinterfacial film stability, limiting the effectiveness of chemicalflooding systems for residual-oil mobilization. To improve the oil-displacementperformance of salt-tolerant surfactant systems, two alkyl polyethersulfonate surfactants with different alkyl chains and polyether structures(CX1 and CX2) were used to construct a mixed surfactant system. Amphiphilicallymodified MoS₂ nanosheets were introduced to investigatetheir synergistic effects on interfacial behavior, wettability alteration,emulsion stability, and enhanced oil recovery performance. The resultsshowed that the CX1/CX2 = 5:5 mass ratio exhibited favorable interfacialactivity in simulated formation water containing Ca²⁺ andMg²⁺. The addition of 0.01 wt % MoS₂ furtherreduced the interfacial tension to 1.49 × 10^–3 mN/m and increased the interfacial storage modulus and loss modulus.Meanwhile, MoS₂ addition reduced water separation, inhibiteddroplet coalescence, and improved droplet-size distribution stability.Contact-angle measurements demonstrated enhanced wettability alteration,with the contact angle decreasing from 38.87° to 28.76°after MoS₂ addition. Core-flooding experiments showed thatrepeated surfactant injection produced only 1.19% incremental oilrecovery, whereas the surfactant–MoS₂ compositesystem achieved an additional recovery of 6.10% with a final oil recoveryof 56.10%. The enhanced oil-displacement performance was attributedto the synergistic effects of interfacial film strengthening, wettabilityalteration, emulsion stabilization, and residual-oil mobilization.

The preparation, characterizationof materials, and electrochemicalperformance of trigonal W₂N thin film as the anode materialfor lithium-ion batteries have been reported. The trigonal W₂N thin film with the space group of P3̅ was synthesized bythe sputtering deposition followed by a nitridation treatment. Thefirst-principles calculations reveal that the adsorption energy ofLi⁺ on the (001) crystal plane of trigonal W₂N is −1.55 eV and the Li⁺ diffusion energy barrieris only 0.23 eV, indicating a significant kinetic superiority forrapid Li⁺ transport. The results of electrochemical testsdemonstrate that the trigonal W₂N thin-film electrode maintainsa stable specific capacity of 700 mA h g^–1 at thecurrent density of 0.1 A g^–1 after 100 cycles. Evenat the current density of 1 A g^–1, the specificcapacity is initially decreased but subsequently rebounded, finallyretaining that at 680 mA h g^–1 after 300 cycles.The results of cyclic voltammetry and ex situ XPS analyses confirmthat the lithium storage mechanism involves Li⁺ intercalation/deintercalationand a reversible conversion reaction. Owing to its high specific capacity,good cycling stability, and superior rate performance, the trigonalW₂N thin-film electrode offers a promising research directionfor high-performance anode materials of thin-film lithium-ion batteriesin the future.

Protonexchange membrane fuel cells (PEMFCs) deployedin aviation,underwater, and space applications encounter different combinationsof environmental and mission constraints. These include altitude-dependentoxygen supply, flight-load transients, closed reactant loops, constrainedheat rejection, and gravity-dependent two-phase transport. The resultingchanges in reactant supply, water–thermal balance, and degradationcomplicate system integration. Intelligent methods can support rapidmodeling, state estimation, health management, and constrained control,yet their applicability depends on the operating environment and validationevidence. This review connects environment-specific mechanisms withmodeling and deployment requirements, distinguishing three evidencelevels: direct studies under representative extreme conditions, studiesreproducing individual relevant stressors, and transferable methodsestablished under conventional PEMFC conditions. The synthesis identifiesgaps in data representativeness, cross-domain generalization, physicalconsistency, uncertainty assessment, and closed-loop validation. Anintegrated physics–data–decision framework is then proposedto connect environment-aware modeling, state and health estimation,risk-aware control, and staged validation. Its purpose is to guidemethod selection and identify the evidence needed for reliable onboardoperation in aerial, underwater, and space systems.

Modelbiomass-derived syngas provides a controlled multicomponentfeed for evaluating CH₄ and CO₂ conversion underconditions representative of the principal gaseous components of biomassgasification gas. In this study, an integrated catalytic membranedesign was developed, in which a CeO₂–Ni@SiO₂ core–shell catalyst was incorporated into a denseH₂-separating Ni membrane for the conversion of CH₄ and CO₂ in model biomass-derived syngas. The tailoringof the fine SiO₂ shell not only improved the reducibilityand accessibility of Ni active species but also mediated the mesoporousdiffusion channel for controlled transport of gaseous reactants. Coupledwith in situ H₂ removal through the Ni membrane, the core–shellcatalyst achieved CH₄ and CO₂ conversions of91.6% and 52.8% at 750 °C, respectively, corresponding to increasesof more than 50% and 25% compared with the fixed-bed counterpart.In addition, stable operation with negligible carbon deposition wasmaintained for approximately 200 h. This work demonstrates that theCeO₂–Ni@SiO₂ coupled Ni membrane reactorprovides an effective strategy for the controlled conversion of modelbiomass-derived syngas and simultaneous H₂ recovery.

Electrochemicalreduction of CO₂ to high-value C₂₊ productsrepresents a promising route for achieving a sustainablecarbon cycle, yet its practical application is hindered by intrinsicchallenges in catalyst design, reaction pathways, and carbonate precipitation,which affect the efficiency, selectivity, safety, and lifespan ofelectrolyzers. This review systematically reorganizes the CO₂-to-C₂₊ electrocatalysis literature around an explicitfour-dimension × four-scale matrix (4D × 4S), where thefour dimensions are materials engineering (I), confinement/tandem(II), microenvironment/interface regulation (III), and reactor/operation(IV), and the four scales are electronic structure, atomic-to-molecularreaction network, mesoscopic transport, and device-reactor performance.This review draws on representative experimental and computationalstudies in CO₂-to-C₂⁺ electrocatalysisrather than attempting an exhaustive catalog. We have the followingmain conclusions: (i) atomic-site design shall cooptimize with mesoscaleconfinement and microenvironment to achieve higher selectivity atindustrial current densities; (ii) membrane-electrode-assembly lifetime,not peak performance, is the central bottleneck for C₂₊ commercialization, with salt precipitation and cation crossoveras the dominant failure modes²; (iii) several materialclasses (atomically defined paired sites, conductive MOFs/COFs, etc.)can maintain high Faraday efficiency of their respective specificC₂₊ products at industrial current densities, but eachfaces a characteristic trade-off (e.g., lifetime vs. selectivity)that no single optimization strategy can resolve; (iv) Cross-scaletheoretical–experimental closure, enabled by operando spectroscopy,machine-learning surrogates, and physics-informed neural networks,is the most promising direction for accelerating the field. The 4D× 4S matrix provides a reusable scaffold for designing and evaluatingthe next generation of C₂₊ electrocatalysts and electrolyzers,with standardized operando datasets and community-accepted validationprotocols as the immediate priorities. We expect that CO₂-to-CO will be the realistic first commercial target, with C₂₊ products as a longer-term goal contingent on substantialcatalyst and membrane innovation.

In this study, a series of nonaqueous deep eutectic solvents(DESs)with dual amino sites were facilely constructed, among which the optimalDES (AEtMImBr: MEA (1:5)) achieved a CO₂ capture capacityof 0.204 g/g at 333.15 K and 1 bar. Moreover, this DES maintainedstable performance after eight absorption–desorption cyclesand under humid conditions with 10 wt % water addition. Finally, theformation of the DES and the CO₂ absorption process atthe molecular level were investigated via both experimentaland theoretical approaches.

Supercritical carbon dioxide (ScCO₂) fracturingis animportant stimulation technology for enhancing coalbed methane production,and microfracture evolution directly affects the seepage capacityof coal reservoirs. To reveal the evolution and transformation mechanismof ScCO₂-induced microfractures under true triaxial stressconditions, fracturing experiments were conducted under two horizontalstress-difference conditions and different injection flow rates. Imageprocessing was used to analyze the distribution, structure, connectivity,and complexity of microfractures. The results showed that microfracturesexhibited clear anisotropy after ScCO₂ fracturing. Themaximum horizontal stress direction (σ_H) had thehighest fracture connectivity and complexity and dominated fracturenetwork development, whereas the minimum horizontal stress direction(σ_h) was mainly characterized by simple and isolatedmicrofractures, and the vertical principal stress direction (σ_v) showed transitional characteristics. Under the higher horizontalstress-difference condition, fracture directionality became stronger,and complex microfractures were mainly concentrated in the σ_H direction, providing more favorable conditions for seepagepathway development. Connectivity and fractal analyses further showedhigher connected microfracture area, intersection count, and fractaldimension in the σ_H direction. Injection flow rateand the principal-stress configuration jointly affected microfractureevolution. Under a low stress difference, increasing injection flowrate enhanced fracture connectivity and complexity. Under a high stressdifference, fracture evolution first increased and then became limited,with fluid-driven effects becoming more pronounced at higher injectionflow rates. SEM observations showed microfracture formation and propagation,mineralized interface detachment, and local closure. T-shaped connectionspromoted the connection between natural fractures and new microfractures,forming a multiscale fracture network. These results provide a basisfor microfracture transformation and seepage capacity enhancementin coal reservoirs by ScCO₂ fracturing.

Photoelectrochemical (PEC) CO₂ reduction ishinderedby sluggish kinetics, poor selectivity, and competing hydrogen evolution.Herein, a g-C₃N₄/Ag-melamine coordination polymer(AgM-CP) heterostructure is developed to enhance CO₂ conversionperformance. Incorporation of Ag modulates the electronic structure,improves light absorption, and promotes selective syngas productionwithout forming liquid byproducts. The catalyst achieves a total currentdensity of 52 mA cm^–2, with ca. 15 mA cm^–2 attributed to CO₂ reduction at −1.48 V vs RHE.Under illumination, a maximum CO generation rate of (269.0 ±13.4) μmolcm^–2h^–1 is achieved,with a higher CO/H₂ ratio at −0.88 V, which declinesat more negative potentials. The I–V curve for g-AM collected under chopped illumination exhibitsa moderate photocurrent density of 0.07 mA cm^–2 at−0.88 V vs RHE. Reduction of Ag⁺ partially consumeselectrons, slightly lowering Faradaic efficiency. The g-AM exhibitsimpressive applied bias photon-to-current efficiency of ca. (1.75± 0.1) % at −1.08 V vs RHE. Interfacial wettability andlocal CO₂/H₂O concentrations govern activity;Tafel analysis shows first electron transfer limits, while low charge-transferresistance enhances CO production at lower bias.