Energy & Fuels最新文献

Salinity gradient, or “blue”, energy offers a sustainable route to convert the chemical potential difference between seawater and freshwater into electricity. Monolayer molybdenum disulfide (MoS₂) has recently emerged as a promising nanofluidic material owing to its atomic thickness, chemical stability, and tunable surface charge. Here, we investigate the scaling behavior of salinity-gradient energy harvesting using chemical vapor deposition (CVD)-grown monolayer MoS₂ membranes containing 20 nm nanopores suspended on silicon nitride substrates. Ion transport measurements were conducted in an automated diffusion cell with large reservoirs (10 L) to ensure stable bulk concentrations under KCl gradients from 10 to 1000. The generated osmotic power increases with nanopore number, rising from 84 nW (single pore) to 230 nW (four pores), corresponding to power densities of (0.1–0.3) × 10⁶ W m^–2 at low porosities (0.04–0.16%). The observed increase in current and power with rising salinity reflects surface-charge-influenced ion transport combined with high ionic flux through atomically thin nanopores. Poisson–Nernst–Planck simulations performed using experimentally relevant geometries reproduce the observed scaling trends and suggest that ionic transport through multiple nanopores can be treated as approximately additive under the present pore spacing. These findings provide fundamental insight into nanoscale ion transport and power scaling in CVD-grown MoS₂ nanopore membranes, informing the development of scalable nanofluidic blue-energy systems.

The escalating energy demand has positioned biodiesel at the forefront of the global transition toward clean energy. As transesterification is a key pathway for biodiesel production, improving its efficiency requires the development of economic and sustainable catalysts. Waste-derived carbonaceous catalysts provide economically and ecologically sustainable alternatives in this regard. This Perspective presents an extensive analysis of emerging carbonaceous catalysts, highlighting the correlation between catalyst synthesis and its compositional-structural properties. This study further deciphers the stimulant influence of surface textural properties, acid–base functionalities, and reaction parameters on the underlying transesterification mechanistic pathways across various feedstocks. Furthermore, the sustainability dimensions of the transesterification process were evaluated through life-cycle assessment and technoeconomic prospects. Advanced characterization techniques, including Extended X-ray absorption fine structure (EXFAS), transmission electron microscopy (TEM), BET, X-ray diffraction (XRD), FTIR, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Raman spectroscopy, are explained to help understand the link between the structure and catalytic activity. Previously, experimental and empirical approaches have been used to optimize transesterification. However, this study proposes the use of advanced data-driven approaches, such as artificial intelligence (AI) and machine learning (ML), for recognizing reaction mechanisms and catalyst design owing to their strong predictive and interpretable capabilities. While previous studies primarily cover conventional catalysts and AI for only parameter optimization, this review uniquely intertwines carbonaceous catalysts with transesterification by integrating catalytic mechanisms with AI and catalyst compositional descriptors.

The dynamic evolution of permeability during depressurization-driven production plays a critical role in determining the deliverability of natural gas hydrate (NGH) reservoirs. The reliability of nuclear magnetic resonance (NMR)-based permeability models fundamentally hinges on the accurate determination of the transverse relaxation time cutoff (T₂ cutoff, T_2C). However, conventional empirical approaches for T_2C determination perform poorly in fine-grained sediments and hydrate-bearing formations, posing a major bottleneck to the broader application of NMR techniques. To overcome this limitation, this study introduces a fully automated and physically interpretable framework for Automated Dual T₂ Cutoff Determination via Wavelet-Gaussian Decomposition, termed ADWD. This method combines multiscale wavelet peak detection with multilog-Gaussian spectral fitting to objectively identify clay-bound and free-fluid T_2C values. Building on these objectively derived fluid partitions, we develop a physically interpretable permeability model (K_ADWD) that integrates effective flow porosity and bound porosity to reflect pore-structure controls on fluid transport, and field validation shows that our model significantly outperforms classical Coates and SDR models in both hydrate-bearing and hydrate-free intervals. In addition, an ADWD flow-through critical transition criterion is proposed to facilitate the recognition of critical low-permeability transitions. Overall, this study overcomes the applicability limitations of traditional T_2C selection and permeability modeling, providing a more reliable petrophysical evaluation tool for assessing the development potential of NGH and other unconventional reservoirs, with strong implications for both theoretical advancement and engineering practice.

The conversion of ethanol to 1,3-butadiene (ETB) as an economic strategy in chemical production still faces the challenge of relatively low yield of 1,3-butadiene (BD). Herein, a series of hierarchical nanosized xZnyZr/S-1 catalysts were prepared using ultrasonic-assisted crystallization followed by an incipient wetness impregnation method for the direct ETB reaction. The characterization results, including XRD, TEM, TEM-EDS, XPS, CO₂-TPD, NH₃-TPD, and Py-IR, indicate that the yield of BD is positively correlated with the nanohierarchical structure and appropriate acid–base properties as well as the synergistic effects of various active centers, and the 8Zn2Zr/S-1 catalyst with an optimal Zn/Zr mass ratio of 4:1 exhibits excellent ETB activity with an ethanol conversion of 82.9% and BD selectivity of 70.2% under mild reaction conditions (350 °C, 101.325 kPa, and 5 h^–1).

As a key parameter determining fluid flow dynamics, it is significant to determine the dynamic permeability evolution during the hydrate phase transition in consideration of media deformation for the safe and efficient development of hydrate-bearing sediments. In this work, a novel methodology of constructing unstructured hydrate-bearing networks with complex morphologies and anisotropy, respectively, in grain-coating and pore-filling hydrate pore habits coupling media deformation was proposed for the first time. After the validation, dynamic permeability evolution regularity considering media deformation was predicted and analyzed. Furthermore, the impact of parameters related to media deformation on the effective pore structure and dynamic permeability evolution was studied in detail. Results indicate that the effective permeability turns smaller, while the decline rate decreases with increasing hydrate saturation due to the difference in the number and compression degree of hydrate-occupied and unoccupied pore elements induced by media deformation. Moreover, the media deformation effect on the effective pore structure intensifies with an increase in the effective stress, a decrease in the elastic modulus, and a reduction in Poisson’s ratio, resulting in a larger decrease in the effective pore-throat radii and reduction in dynamic permeability at the same hydrate saturation. In addition, the number of hydrate-occupied pore bodies and throats grows smaller at the same increment in hydrate saturation as media deformation becomes more pronounced, leading to a slower decline rate and a smaller difference in dynamic permeability with different media deformation parameters.

To address the severe lost circulation challenges in shallow fractured formations with centimeter-scale fracture widths and vuggy structures, this study developed a novel gel plugging material (CPM series) composed of water-absorbing/swelling components (e.g., polyacrylamide), a glyoxal cross-linker, and inert skeleton materials. The sealing performance of the material was systematically evaluated. The plugging mechanism under high-pressure flushing conditions was investigated with a custom-designed simulation device capable of replicating centimeter-scale fractures. The results showed that the optimized formula CPM-2 (water absorption component at 50%, cross-linking agent at 15%, and inert material at 35%) had the best comprehensive performance. The material demonstrated a water absorption rate of 700%, retaining a swelling ratio of 580% even in a 5% brine solution. The shear strength was 2.13 MPa (5 MPa normal stress). The maximum pressure-bearing capacity of the plugging body formed by the material in the simulated wedge seam and step seam was 5.1 MPa, and the pressure-bearing capacity increased with the increase of the temperature. The plugging body formed an interpenetrating network skeleton through water absorption and swelling, exhibiting a three-stage evolution of water absorption expansion–plastic–densification strengthening during compaction. Failure in wedge-shaped fractures primarily occurred via extrusion at the outlet, while stepped fractures experienced multi-stage, step-by-step breakdown at the fracture tips. In comparison to traditional bridging materials, this gel material solves the problems of particle size mismatch and scouring failure in centimeter-scale fractures through a rapid phase transition (achieving 85% expansion within 20 min) and adaptive filling capability. The new gel material provides a new solution for managing severe lost circulation in shallow fractured reservoirs, demonstrating a significant value for engineering applications. Furthermore, with laboratory plugging experiments conducted specifically for centimeter-scale fracture widths, this study provides a theoretical basis for the engineering design of plugging operations targeting fractures of centimeter-scale width.

Phytoremediation is receiving increasing attention as an environmentally friendly remediation technique for contaminated soils, as it can target different contaminants, such as heavy metals. Phytoremediation processes produce large volumes of contaminated biomass that must be disposed of and possibly valorized. Among the possible treatments for heavy metal-contaminated biomass, a promising approach is to pyrolyze these biomasses. However, it must be considered that heavy metals can interact with the biomass pyrolysis decomposition pathways, resulting in variations in the yields and properties of pyrolysis products. In this work, the effects of lead (Pb) contamination on poplar biomass during slow pyrolysis were investigated. In particular, the focus of this paper is on the effect of the type of bonding of Pb with the biomass tissue, which is specific to the contamination type (authigenic or detrital), and on the effect of the chemical speciation of Pb. To study these aspects, poplar biomass was opportunely doped with lead acetate (Pb(CH₃COO)₂) following different procedures aimed at simulating different bonds between Pb and biomass tissues. Moreover, to study the effect of Pb chemical speciation, poplar biomass was also doped with lead nitrate (Pb(NO₃)₂). All the doped feedstocks, together with the parent biomass, were pyrolyzed under slow pyrolysis conditions at two pyrolysis temperatures (465 and 600 °C), and the obtained products, namely, biochar, bio-oil, and pyrolysis gases, were analyzed thoroughly. The obtained results show that the presence of Pb can indeed modify the pyrolysis pathways of lignocellulosic biomasses. The different bonding of Pb with biomass causes modifications in the yield of the liquid products. On the other hand, changing the Pb chemical speciation cause variations in the properties of all pyrolysis products. However, the extent of many Pb effects seems to be affected by the presence of inherent inorganics, such as alkali and alkali-earth metals (AAEMs).

In this study, the thermal degradation of high-density polyethylene (HDPE) microplastics was investigated to obtain and characterize the liquid fraction generated by vacuum pyrolysis, assessing its potential for energy valorization as an alternative fuel. The methodology included thermo-chemical characterization and mathematical modeling of HDPE based on thermogravimetric analyses conducted at heating rates of 5, 10, 15, 20, and 25 °C min^–1, differential scanning calorimetry (DSC), and vacuum pyrolysis performed under the following operational conditions: 550 °C, −100 mmHg, and a residence time of 90 min. The resulting oily liquid product was characterized by gas chromatography–mass spectrometry (GC-MS) and by high-resolution mass spectrometry (HRMS) using direct infusion with electrospray ionization and atmospheric pressure chemical ionization sources. The DTG and DSC results indicated that the onset of thermal degradation of the HDPE molecular chains occurred at approximately 500 °C. The comparison between experimental and predicted data demonstrated good agreement, validating the applicability of these methods for modeling the thermal degradation kinetics. The GC-MS analysis revealed that the liquid fraction is composed mainly of hydrocarbons, particularly alkanes (saturated chains) and alkenes (unsaturated chains). Furthermore, HRMS analysis confirmed, through Van Krevelen diagrams, that the liquid product is highly heterogeneous, exhibiting a predominance of linear and saturated alkanes similar to those found in light oils. Minor contributions from O_x[H] and N_xO_y[H] classes were also detected, likely associated with impurities and highly condensed aromatic species formed via aromatization and polycondensation reactions during pyrolysis.

To investigate the deformation characteristics of nondiagenetic hydrate under depressurization, this study conducted triaxial tests systematically controlling hydrate saturation (S_h), sediment matrix, depressurization procedure, and effective axial stress (σ₁′). Gas production and axial deformation were monitored in real time, revealing the settlement deformation characteristics of nondiagenetic hydrate-bearing sediments under multifactor control. The results show: (1) The hydrate decomposition process is characterized by three stages: “undecomposed, rapidly decomposed, continuously decomposed”. (2) Increased S_h significantly enhanced total gas production and axial deformation. Conversely, coarser sediment matrix particles significantly reduced axial deformation while exerting negligible influence on total gas yield. (3) Larger depressurization magnitudes intensified settlement deformation. However, drastic temperature drops could trigger secondary hydrate formation and redissociation, reducing dissociation efficiency. (4) Lower σ₁′ reduced the amount of deformation. As dissociation is primarily governed by thermodynamic phase equilibrium, variations in stress have a limited impact on total gas production. These results elucidate the critical influence of reservoir matrix properties and depressurization strategies on gas production and deformation in nondiagenetic hydrate reservoirs, providing a theoretical basis for their safe exploitation.

The current challenge of storing energy has become more critical than ever, particularly with the emergence of intermittent renewable energy resources. Deep eutectic solvents (DESs) have become promising multitasking agents for a wide spectrum of energy-related applications. Among these, energy storage is currently regarded as a simultaneously challenging and yet a promising research area, aiming to maximize energy harvesting from renewable sources. Polymer-inspired DESs (PIDESs) and polymeric-based DESs (PDESs) represent novel opportunities for electrochemical energy storage and conversion (EESC) technologies, as their fundamental functionalities offer an intriguing pathway for developing next-generation EESC systems with high performance, a wide electrochemical window, and extended lifespan. This review sheds light on the recent applications of PIDESs and PDESs in EESC devices, including fuel cells, Li-, Al-, Zn-, Na-, and Mg-based batteries, and supercapacitors. It additionally identifies current gaps and how exploiting these neoteric agents can maximize device efficiency and facilitate controlled design. Finally, this review outlines the future potential of PIDESs and PDESs and their significance in this rapidly evolving field. To the best of our knowledge, this is the first review that encompasses the roles of PIDESs and PDESs in energy storage systems.