Visualization study of the effects of polycarboxylates on CO hydrate generation and interfacial property.

Marine carbon sequestration, with its high potential and low risk of leakage, is an attractive technology for effectively addressing global climate change and reducing greenhouse gas emissions. A current concern about marine sequestration lies in the potential negative effects of the carbon sequestration process on the marine environment. CO hydrate sequestration is considered to be one of the most stable method of sequestration, and researchers are actively searching for promoters that facilitate hydrate sequestration and are friendly to the marine environment.

Spontaneous Lifting and Self-Cleaning of Gas Hydrate Crystals.

Crystal fouling, which refers to the accumulation of precipitates on surfaces and the associated damage, is a common problem in many industrial processes. In deepwater oil and gas transportation, hydrate blockage poses as a considerable barrier. Consequently, modifying hydrophobicity of surfaces has become an increasingly focused strategy to mitigate hydrate.

An x-ray computed tomography gas hydrate in situ formation and seepage simulation device.

Nano-CT (computed tomography) technology enables high-resolution imaging and scanning of hydrate dissociation processes in porous media at submicron-scale resolution. However, due to the inability of nano-CT to withstand large torque, the traditional semiconductor cooling method cannot be used for in situ hydrate formation, resulting in the hindering of the effective operation of seepage simulators. Therefore, in this paper, a nano-CT-based in situ hydrate formation and seepage simulator are specially designed, and the torque and entanglement problems existing in traditional experimental devices can be solved by using a pipeline placed above the device and a built-in seepage line.

Hydrogen and Cushion Gas Adsorption-Desorption Dynamics on Clay Minerals.

Transitioning toward a hydrogen (H)-centric energy paradigm necessitates understanding the adsorption properties of clay minerals, essential constituents of reservoirs and caprocks, for efficient geological H storage. This study examines the adsorption characteristics of H on various clay minerals (montmorillonite, illite, chlorite, kaolinite, and sepiolite) at different temperatures and the adsorption of cushion gases (N, CH, and CO) under reservoir conditions (313.15 K, up to 10 MPa).

Pore-scale deformation characteristics of hydrate-bearing sediments with gas replacement.

Gas replacement method enables the simultaneous exploitation of natural gas and the realization of carbon capture, utilization, and storage (CCUS). Safe exploitation of hydrate-bearing sediments (HBS) has garnered significant attention, particularly concerning the engineering geological risks involved. Understanding deformation characteristics during shear after the replacement of HBS is crucial for safe and efficient exploitation.

Dependence of the formation kinetics of carbon dioxide hydrate on clay aging for solid carbon dioxide storage.

Clay-based marine sediments have great potential for safe and effective carbon dioxide (CO) encapsulation by storing enormous amounts of CO in solid gas hydrate form. However, the aging of clay with time changes the surface properties of clay and complicates the CO hydrate formation behaviors in sediments. Due to the long clay aging period, it is difficult to identify the role of clay aging in the formation of CO hydrate in marine sediments.

Investigation on multi-parameter of hydrate-bearing synthetic sediment during hydrate replacement process: A in-situ X-ray computed tomography study.

Carbon sequestration can be achieved by carbon dioxide replacement in natural gas hydrate exploitation, which reducing greenhouse gas emissions and providing an effective solution to address climate change, while simultaneously protecting the environment and promoting sustainable energy development. Gas replacement can achieve gas exploitation, gas storage, and stability enhancement simultaneously. However, time-varying microstructure evolution of the hydrate-bearing sediment (HBS) during this process remain a large amount of uncertainty.

Lattice dynamics and heat transport in zeolitic imidazolate framework glasses.

The glassy state of zeolitic imidazolate frameworks (ZIFs) has shown great potential for energy-related applications, including solid electrolytes. However, their thermal conductivity (κ), an essential parameter influencing thermal dissipation, remains largely unexplored. In this work, using a combination of experiments, atomistic simulations, and lattice dynamics calculations, we investigate κ and the underlying heat conduction mechanism in ZIF glasses with varying ratios of imidazolate (Im) to benzimidazolate (bIm) linkers.

Methane hydrate phase equilibrium considering dissolved methane concentrations and interfacial geometries from molecular simulations.

Natural gas hydrates, mainly existing in permafrost and on the seabed, are expected to be a new energy source with great potential. The exploitation technology of natural gas hydrates is one of the main focuses of hydrate-related studies. In this study, a large-size liquid aqueous solution wrapping a methane hydrate system was established and molecular dynamics simulations were used to investigate the phase equilibrium conditions of methane hydrate at different methane concentrations and interfacial geometries.

Facilitation of Hydrate Dissociation and Structural Evolution by Major Marine Anions under Static Electric Fields.

Electric fields have been proven to be capable of significantly affecting the equilibrium state of hydrates. In this study, the thermodynamic properties and structural changes of methane hydrate (MH) in various anion solutions in an electric field at 0.7 V/nm were investigated by molecular dynamics simulations.

Heat Transport in Clathrate Hydrates Controlled by Guest Frequency and Host-Guest Interaction.

The underlying mechanism of common limited lattice thermal conductivity (κ) in energy-related host-guest crystalline compounds has been an ongoing topic in recent decades. Here, the guest-triggered intrinsic ultralow κ of the representative xenon clathrate hydrate was investigated using the time domain thermoreflectance technique and theoretical calculations. The localized guest modes were observed to hybridize with acoustic branches and severely limit the acoustic κ contribution.

Monolithic MXene Aerogels Encapsulated Phase Change Composites with Superior Photothermal Conversion and Storage Capability.

The inherently intermittent feature of solar energy requires reliable energy conversion and storage systems for utilizing the most abundant solar energy. Phase change materials are potential solutions to store a large amount of heat produced by solar light. However, few of the phase change materials have the ability to efficiently convert solar energy into heat; additionally, phase change materials need to be encapsulated in porous substrates for enhancing their leaking resistance and photo-to-thermal performance.

Clay nanoflakes and organic molecules synergistically promoting CO hydrate formation.

Carbon dioxide (CO) reduction is an urgent challenge worldwide due to the dramatically increased CO concentration and concomitant environmental problems. Geological CO storage in gas hydrate in marine sediment is a promising and attractive way to mitigate CO emissions owning to its huge storage capability and safety. However, the sluggish kinetics and unclear enhancing mechanisms of CO hydrate formation limit the practical application of hydrate-based CO storage technologies.

Three-body aggregation of guest molecules as a key step in methane hydrate nucleation and growth.

Gas hydrates have an important role in environmental and astrochemistry, as well as in energy materials research. Although it is widely accepted that gas accumulation is an important and necessary process during hydrate nucleation, how guest molecules aggregate remains largely unknown. Here, we have performed molecular dynamics simulations to clarify the nucleation path of methane hydrate.

Promoting Effect of Common Marine Cations on Hydrate Dissociation and Structural Evolution under a Static Electric Field.

Natural gas hydrate, a potential energy resource, is attracting worldwide attention. In this study, we propose a new method of hydrate dissociation which uses seawater and electrostatic fields (SE method) cooperatively. The hydrate molecular dissociation mechanism of gas hydrate is a key issue in studying the kinetic properties of gas hydrate using the SE method.

Fractal analysis on CO hydrate-bearing sands during formation and dissociation processes with NMR.

Injecting CO into submarine sediments to form hydrates is one of the potential methods of CO sequestration. The transition behavior of CO hydrates in porous media is of great practical significance. In this work, CO hydrate formation/dissociation in porous media was monitored in real time by a low-field magnetic resonance (MR) system, and a series of dynamic fractal dimensions of the pore space occupied by converted water during the hydrate formation/dissociation process were obtained based on the transverse relaxation time (T) distributions.

Effects of ice and supercooled water on the metastability of methane hydrate: DSC analysis and MD simulations.

Methane hydrate (MH) has been viewed as a potential abundant clean energy resource worldwide. Its related technologies play important roles in applications of gas and energy storage, flow assurance of natural gas pipelines Unlike the well-researched stability and decomposition of MH at temperatures above 273 K, the metastability of MH below the ice freezing point, the anomalous slow decomposition out of thermodynamically stable regions, remains to be unravelled. Studies regarding the influences of ice and supercooled water (SW) on the metastable properties of MH led to varied conclusions, the as-proposed self-preservation effect and metastable MH-SW-gas equilibrium.

Magnetically Recyclable -SO-Coated Nanoparticles Promote Gas Storage via Forming Hydrates.

Efficient gas enrichment approaches are of great importance for the storage and transportation of clean energy and the sequestration of carbon dioxide. Of special interest is the regulated gas hydrate-based method; however, its operation requires adequate additives to overcome the low-storage capacity issue. Thus, this method is not economically feasible or environmentally friendly.

Kinetic process of upward gas hydrate growth and water migration on the solid surface.

Gas hydrates have gained great interest in the energy and environmental field as a medium for gas storage and transport, gas separation, and carbon dioxide sequestration. The presence of small doses of surfactants in the aqueous phase has been reported to enhance hydrate formation; however, the underlying mechanisms remain poorly understood. Thus, in situ high-resolution X-ray computed tomography measurements were performed to monitor the upward water migration and the resulting hydrate nucleation and growth.

Molecular behavior of hybrid gas hydrate nucleation: separation of soluble HS from mixed gas.

Soluble HS widely exists in natural gas or oil potentially corroding oil/gas pipelines. Furthermore, it can affect the hydrate formation condition, resulting in pipeline blockage; the nucleation mechanism from mixed gas including HS is still largely unclear. Molecular dynamics simulations were performed to reveal the effects of different initial mixed HS/CH compositions on the hydrate nucleation and growth process.

Evidence of Guest-Guest Interaction in Clathrates Based on Raman Spectroscopy and Density Functional Theory.

Isotopes are ideal substances for studying the intermolecular interactions in clathrates by replacing the atoms without destroying the geometry structure. When methane (CH) in the spatially homogeneous methane hydrate was replaced with deuterated methane (CD), it showed a previously unrecognized strong anharmonic effect, identified by the Raman peak located at 1952.78 cm.

Fast Peel-Off Ultrathin, Transparent, and Free-Standing Films Assembled from Low-Dimensional Materials Using MXene Sacrificial Layers and Produced Bubbles.

Ultrathin, transparent, and free-standing films assembled from low-dimensional nanomaterials (LDMs) are promising for various applications, including transparent heaters and membranes. However, the intact separation of the assembled films, especially those with controlled ultrathin thickness from deposited substrates, is a tremendous challenge, particularly for fast peeling off via self-detaching. Herein, we propose a versatile method to rapidly peel off ultrathin assembled LDM films, including three types of carbon nanotubes, vermiculite, Ag nanowires, and carbon nanotube@graphene, by dissolving the MXene interlayer from the layer-by-layer filtered MXene/LDM Janus films using diluted H O .

Molecular simulations on the stability and dynamics of bulk nanobubbles in aqueous environments.

Nanobubbles have attracted significant attention due to their unexpectedly long lifetimes and stabilities in liquid solutions. However, explanations for the unique properties of nanobubbles at the molecular scale are somewhat controversial. Of special interest is the validity of the Young-Laplace equation in predicting the inner pressure of such bubbles.