Nanoporous Structure Research Articles

Nanopore structure and fractal characteristics of sandstone after high-temperature action

Nanopore structure and fractal characteristics of sandstone after high-temperature action

Investigating the influence of pore-widening time control in electrochemical anodization for the formation of hybrid titanium nanostructures with enhanced superhydrophobicity for improved corrosion resistance efficiency

Titanium (Ti) alloys possess remarkable strength, high-temperature stability, and processability, making them indispensable in biomaterials, aircraft engines, fuselage manufacturing, and ship propulsion shafts. However, when exposed to potential differences or minor defects in contact with other alloys, the thin natural oxide film on their surface is vulnerable to damage, leading to accelerated corrosion or diminished stability. This study investigated the morphology of the final oxide film formed with varying pore-widening (PW) process time (10–60 min with 10-minute intervals) after the anodization of Ti-Grade 4 material. The oxide films formed from the anodization and the PW process for 10 to 40 min exhibited a porous structure, while a hybrid pillar and pore structure were observed after a PW process of 50 min. As the PW time increases, the pore diameter expands, forming hybrid pillar and pore nanostructures, and superhydrophilicity is observed. After FDTS (1H, 1H, 2H, 2H-Perfluorooctyltrichlorosilane) coating, the phenomenon elucidates the transition from hydrophobicity to superhydrophobicity and the enhancement of water droplet mobility, with the lowest contact angle hysteresis measured at PW of 60 min and demonstrating improved corrosion resistance, achieving a corrosion inhibition efficiency of over 99% compared to the untreated titanium alloy surface. Notably, the structure encompassing pillar and pore features exhibits exceptional suitability for applications on material surfaces and interfacial phenomena, such as cell adhesion. Furthermore, surfaces characterized by excellent superhydrophobicity because of coating can find multifunctional applications encompassing anti-corrosion, anti-fouling, anti-icing, and self-cleaning capabilities.

Nanostructuring and oxygen-vacancy tuning to repress thermal transport and activate thermoelectric properties of green-synthesized ZnO

We introduce eco-friendly synthesized ZnO nanoparticles by using orange peel extract for thermoelectric applications. Orange peel extract plays a crucial role as a reducing and surface-stabilizing agent in the synthesis process. It significantly affects the microstructure and lattice defects governing transport properties and thermoelectric performance of polycrystalline ZnO. A comparison of the structural and thermoelectric properties between the green-synthesized ZnO (ZnO OPE) and commercial ZnO (ZnO com) is conducted. The outcomes indicate that the ZnO OPE sample exhibits a 3.5-time higher electrical conductivity than the commercial ZnO at 1073 K, which is thermally activated at more than 673 K by oxygen vacancies. Moreover, the highly porous nanostructure of the ZnO OPE sample substantially reduces thermal conductivity from 14.5 W/mK to 5.5 W/mK with increasing temperature from 300 to 1073 K. The combination of nanostructure and defect modification paves the way for thermoelectric ZnO-based materials synthesized using environmentally friendly processes.

Dealloyed Pt74Ni26 and Pt26Ni74 Electrodeposited Thin Film Electrocatalysts for Oxygen Reduction

Electrodeposition and microstructure of thin films close to Pt75Ni25 and Pt25Ni75 stoichiometry are described and their catalytic oxygen reduction reaction performance, dealloying, and strain evolution detailed. Multiple techniques are used to characterize the morphology, crystalline structure, and chemical homogeneity of the as-deposited and dealloyed films. A fine-scale percolating network of lower-density regions is evident in the as-deposited Pt74Ni26 films while the as-deposited Pt26Ni74 films are more homogenous and compact. Electrodeposition is accompanied by development of significant in-plane tensile stress that increases at more negative growth potentials to reach 1.28 GPa for as-deposited Pt26Ni74. Dealloying of the near-surface regions of Pt74Ni26 is accompanied by limited expansion or opening of the low-density regions while massive dealloying of the highly stressed Pt26Ni74 results in shrinkage, extensive cracking, and formation of a bi-continuous nanoporous structure with an average pore diameter close to 5 nm. Relative to electrodeposited Pt, the alloy films exhibit enhanced area-specific oxygen reduction reaction activity (at 0.95 V vs RHE, iR-corrected) that amounts to a factor of 3.4 for dealloyed Pt74Ni26 and 5.1 for dealloyed Pt26Ni74 while the Pt-based mass activity increased by a factor of 5.1 and 12.3, for the respective films.

Ten years of laser-induced graphene: impact and future prospect on biomedical, healthcare, and wearable technology.

Since its introduction in 2014, laser-induced graphene (LIG) from commercial polymers has been gaining interests in both academic and industrial sectors. This can be clearly seen from its mass adoption in various fields ranging from energy storage and sensing platforms to biomedical applications. LIG is a 3-dimensional, nanoporous graphene structure with highly tuneable electrical, physical, and chemical properties. LIG can be easily produced by single-step laser scribing at normal room temperature and pressure using easily accessible commercial level laser machines and materials. With the increasing demand for novel wearable devices for biomedical applications, LIG on flexible substrates can readily serve as a technological platform to be further developed for biomedical applications such as point-of-care (POC) testing and wearable devices for healthcare monitoring system. This review will provide a comprehensive grounding on LIG from its inception and fabrication mechanism to the characterization of its key functional properties. The exploration of biomedicals applications in the form of wearable and point-of-care devices will then be presented. Issue of health risk from accidental exposure to LIG will be covered. Then LIG-based wearable devices will be compared to devices of different materials. Finally, we discuss the implementation of Internet of Medical Things (IoMT) to wearable devices and explore and speculate on its potentials and challenges.

Graphdiyne‐Supported Metals and Metal Compounds: Synthesis, Applications, and Future Prospects

AbstractGraphdiyne (GDY) is a 2D carbon allotrope that has become increasingly prevalent among the family of carbon materials. GDY has advantages of high specific surface area and unique sp‐ and sp2‐hybridized carbon atom networks, is endowed with naturally adjustable bandgap, uniformly nanoporous structure, rapid carrier mobility activated by inhomogeneous π orbitals, and accessible on/off rations. These advantages, coupled with the direct binding ability of metal atoms resulting from sp‐hybridization, enable GDY to be applied across various research fields, especially as a substrate to support and further improve the performances of metals and metal compounds. Though many studies have considered the applications of GDY‐supported metals and metal compounds, a comprehensive introduction of synthesis and applications is deficient. Nonetheless, a discussion considering these diverse studies is essential to attract the attention of researchers and promote the development of new perspectives. In this review, a basic understanding of GDY and a thorough introduction to the synthesis and applications of GDY‐supported metals and metal compounds are presented. The review considers nanoparticles, nanoclusters, and dual and single atoms, and concurrently catalogues these in specific application domains. Moreover, future challenges and the development potentials of GDY‐supported materials are discussed to provide different perspectives and ideas.

Tinospora cordifolia-assisted synthesis of silver ferrite nanoparticles: a multifunctional approach to photocatalytic degradation of reactive blue-13 dye, anti-bacterial efficacy, and antioxidant properties

Tinospora cordifolia-assisted synthesis of silver ferrite nanoparticles: a multifunctional approach to photocatalytic degradation of reactive blue-13 dye, anti-bacterial efficacy, and antioxidant properties

Pompon Mum-like SiO2/C Nanospheres with High Performance as Anodes for Lithium-Ion Batteries

SiO2 has a much higher theoretical specific capacity (1965 mAh g−1) than graphite, making it a promising anode material for lithium-ion batteries, but its low conductivity and volume expansion problems need to be improved urgently. In this work, pompon mum-like SiO2/C nanospheres with the sandwich and porous nanostructure were obtained by using dendritic fibrous nano silica (DFNS) and glucose as matrix and carbon source, respectively, through hydrothermal, carbonization and etching operations. The influence of SiO2 content and porous structure on its electrochemical performance was discussed in detail. The final results showed that the C/DFNS-6 with a SiO2 content of 6 wt% exhibits the best electrochemical performance as a negative electrode material for lithium-ion batteries due to its optimal specific surface area, porosity, and appropriate SiO2 content. C/DFNS-6 displays a high specific reversible capacity of 986 mAh g−1 at 0.2 A g−1 after 200 cycles, and 529 mAh g−1 at a high current density (1.0 A g−1) after 300 cycles. It also has excellent rate capability, with a reversible capacity that rises from 599 mAh g−1 to 1066 mAh g−1 when the current density drops from 4.0 A g−1 to 0.2 A g−1. These SiO2/C specific pompon mum-like nanospheres with excellent electrochemical performance have great research significance in the field of lithium-ion batteries.

Recent advances in small-angle scattering techniques for MOF colloidal materials

This paper reviews the recent progress of small angle scattering (SAS) techniques, mainly including X-ray small angle scattering technique (SAXS) and neutron small angle scattering (SANS) technique, in the study of metal-organic framework (MOF) colloidal materials (CMOFs). First, we introduce the application research of SAXS technique in pristine MOFs materials, and review the studies on synthesis mechanism of MOF materials, the pore structures and fractal characteristics, as well as the spatial distribution and morphological evolution of foreign molecules in MOF composites and MOF-derived materials. Then, the applications of SANS technique in MOFs are summarized, with emphasis on SANS data processing method, structure modeling and quantitative structural information extraction. Finally, the characteristics and developments of SAS techniques are commented and prospected. It can be found that most studies on MOF materials with SAS techniques focus mainly on nanoporous structure characterization and the evolution of pore structures, or the spatial distribution of other foreign molecules loaded in MOFs. Indeed, SAS techniques take an irreplaceable role in revealing the structure and evolution of nanopores in CMOFs. We expect that this paper will help to understand the research status of SAS techniques on MOF materials and better to apply SAS techniques to conduct further research on MOF and related materials.

In-situ growth of 3D amorphous Ni-Co-Mn phosphate on 2D Ti3C2Tx nanocomposite for commercial-level hybrid energy storage application

To overcome the limited electronic conductivity and capacity of single and binary transition metal phosphates (TMPs), highly electrochemical active materials and rational structural design of ternary TMPs composite are urgently required. In this study, we successfully synthesized an amorphous 3D Ni-Co-Mn phosphate@2D Ti3C2Tx (MXene) nanocomposite (NCMP series) through the electrodeposition method. The amorphous Ni-Co-Mn phosphate effectively restricts the self-accumulation of MXene nanosheets, resulting in the development of a porous nanostructure. This structure exposes more active sites, expands the ion transport path, and enhances the conductivity of the Ni-Co-Mn phosphate@Ti3C2Tx material. Owing to the synergistic effect offered by Ni-Co-Mn phosphate and MXene nanocomposite, the anchored Ni-Co-Mn phosphate@Ti3C2Tx (NCMP-5) electrode delivers an elevated capacity of 342 mAh/g (1230 C/g) at 5.0 A/g, surpassing the pristine Ni-Co-Mn phosphate (NCMP-4, 260 mAh/g) and MXene (33.3 mAh/g). Moreover, a hybrid solid-state supercapacitor (HSSC) device is assembled with NCMP-5 as a cathode and reduced graphene oxide (rGO) as an anode within a polymer gel (PVA-KOH) electrolyte. Notably, the fabricated HSSC device displays a supreme specific capacity of 27.5 mAh/g (99 C/g) and a high (volumetric) energy density of 22 Wh/kg (3.6 Wh/cm3) at a power density of 0.80 kW/kg (0.13 kW/cm3) for 1.0 A/g. Moreover, the HSSC device retains 95.4 % of its initial capacity even after 10,000 cycles. Importantly, the operational potential window of two serially connected HSSC devices approaches +3.2 V, enabling different colored commercial light-emitting diodes (LEDs) to be efficiently illuminated. Eventually, the remarkable supercapacitive characteristics of the 3D@2D amorphous Ni-Co-Mn phosphate@MXene nanocomposite make it an attractive choice for advanced electroactive materials in upcoming hybrid energy storage technologies.

Nanoporous NiPt alloy by dealloying of amorphous NiZrPt metallic glass for alkaline hydrogen evolution reaction

The development of high-performance and low-cost alkaline hydrogen precipitation catalysts is critical for the large-scale application of hydrogen energy. In this work, the nanoporous alloy catalysts were synthesized by dealloying melt-spun NiZrPt ribbons. The optimal sample after dealloying shows excellent HER performance in alkaline medium, with a small overpotential of 15 mV to deliver 10 mA cm−2 and a low Tafel slope of 20 mV/dec. The material characterization reveals that the incorporation of Ni modulates the electronic structure of Pt. After selective dealloying of Zr and Ni, a Pt-enriched nanoporous structure was formed on the catalyst surface. Meanwhile, the remaining Ni sites acted as synergistic sites to activate the Pt sites, which allowed for better hydrogen adsorption energy and faster kinetics of the catalytic reaction. Besides, the favorable mechanical flexibility of the material makes it potential for self-supporting electrode. This work presents a way to prepare low-Pt efficient catalysts by amorphous alloy dealloying.

Electrochemical Surface Nanostructuring of Ti47Cu38Fe2.5Zr7.5Sn2Si1Ag2 Metallic Glass for Improved Pitting Corrosion Resistance

Ti‐based bulk metallic glasses are envisioned for human implant applications. Yet, while their elevated Cu content is essential for a high glass‐forming ability, it poses biocompatibility issues, necessitating a reduction in near‐surface regions. To address this, surface treatments that simultaneously generate protective and bioactive states, based on nanostructured Ti and Zr‐oxide layers are proposed. An electrochemical pseudo‐dealloying process using the bulk glass‐forming Ti47Cu38Fe2.5Zr7.5Sn2Si1Ag2 alloy is defined. Melt‐spun ribbons are immersed in hot concentrated nitric acid solution, monitoring the anodic polarization behavior. From the current density transient measurements, together with surface studies (field‐emission scanning electron microscopy, transmission electron microscopy, and Auger electron spectroscopy), the surface reactions are described. This nanostructuring process is divided into three stages: passivation, Cu dissolution, and slow oxide growth, leading to homogenous nanoporous and ligament structures. By tuning the applied potential, the pore and ligament sizes, and thickness values are adjusted. According to X‐ray photoelectron spectroscopy, these nanoporous structures are Ti and Zr‐oxides rich in hydrous and nonhydrous states. In a simulated physiological solution, for those treated glassy alloy samples, complete suppression of chloride‐induced pitting corrosion in the anodic regime of water stability is achieved. This high corrosion resistance is similar to that of clinically used cp‐Ti.

Influence of electrolytic plasma spatial distribution on nanoporous structure etching on 4H-SiC surface

Single-crystal SiC nanoporous structure has important applications in the field of micro electromechanical systems, chemical sensors and biomedical devices. However, SiC exhibits a strong chemical inertness due to the short interatomic distance and high binding energy, making it significantly challenging to fabricate nanoporous structure. Electrolytic plasma-assisted chemical etching (EPACE) based on electrochemical anodic oxidation and high-activity electrolytic plasma etching is an ideal method for SiC nanoporous structure etching. In which, the spatial distribution of electrolytic plasma has an important impact on EPACE performance, such as etching efficiency and stability. In order to analyze the impact mechanism, this paper studies EPACE in tool electrode mounting posture of vertical and horizontal types by visual observation, real-time recording of voltage-current waveforms during processing, and the morphology analysis of SiC nanoporous structure after etching. It can be found that in the vertical etching type, EPACE can proceed stably because the workpiece immersion depth is greater than the bubble accumulation thickness. However, in the horizontal etching type, bubbles accumulate seriously between the workpiece and the liquid surface, which may cause bubble cavitation and abnormal discharge, leading to damage to the etching surface. The etching current in the vertical etching type is about 1.3 times that of the horizontal etching type, indicating that the bubble mass transfer in the vertical etching type is faster and the etching impedance is smaller, which is beneficial to improve the etching efficiency and obtain a uniform nanoporous structure. Finally, a SiC nanoporous layer with a thickness of 10.6 μm was prepared at etching time t = 50 min in vertical etching type, and the etching efficiency was 212 nm/min. In addition, the prepared nanoporous structure (nanofiber) was connected to the SiC substrate, indicating that it has a good bonding strength.

Flexible Aerogel Materials: A Review on Revolutionary Flexibility Strategies and the Multifunctional Applications.

The design and preparation of flexible aerogel materials with high deformability and versatility have become an emerging research topic in the aerogel fields, as the brittle nature of traditional aerogels severely affects their safety and reliability in use. Herein, we review the preparation methods and properties of flexible aerogels and summarize the various controlling and design methods of aerogels to overcome the fragility caused by high porosity and nanoporous network structure. The mechanical flexibility of aerogels can be revolutionarily improved by monomer regulation, nanofiber assembly, structural design and controlling, and constructing of aerogel composites, which can greatly broaden the multifunctionality and practical application prospects. The design and construction criterion of aerogel flexibility is summarized: constructing a flexible and deformable microstructure in an aerogel matrix. Besides, the derived multifunctional applications in the fields of flexible thermal insulation (flexible thermal protection at extreme temperatures), flexible wearable electronics (flexible sensors, flexible electrodes, electromagnetic shielding, and wave absorption), and environmental protection (oil/water separation and air filtration) are summarized. Furthermore, the future development prospects and challenges of flexible aerogel materials are also summarized. This review will provide a comprehensive research basis and guidance for the structural design, fabrication methods, and potential applications of flexible aerogels.

Enhanced charge transfer via NH2-MIL-125@ NH2/H-MIL-125 hetero-frameworks for photocatalytic H2 evolution

The efficient transfer of photogenerated carriers is essential to the photocatalytic H2 evolution. Herein, we designed and synthesized a kind of novel NH2-MIL-125@NH2/H-MIL-125 hetero-frameworks with nanopore structure to drive efficient charge transfer for photocatalytic H2 evolution. Single-ligand NH2-MIL-125 (NM) and dual-ligand NH2/H-MIL-125 (NHM), which have similar composition, structure and well-matched energy band, were selected as the core and shell to prepare the NM@NHM hetero-framework as a proof-of-principle system. The hetero-framework strategy is proposed to intensify the charge transfer and thus enhance the photocatalytic activity. The H2 evolution rate of optimal NM@NHM hetero-framework can reach 2.25 mmol g−1 h−1 under visible light, much higher than pristine NM (0.726 mmol g−1 h−1) and NHM (1.27 mmol g−1 h−1). Such high performance can be attributed to the hetero-framework structure consisting of NM and NHM with similar composition and structure, which reduces the interfacial resistance in the charge transfer, thus facilitating the photocatalytic H2 evolution. Our work may provide a new strategy for the rational design of high-performance photocatalysts.

Confined Water Dynamics in the Scaffolds of Polylactic Acid.

Resorbable polylactic acid (PLA) ultrathin fibers have been applied as scaffolds for tissue engineering applications due to their micro- and nanoporous structure that favor cell adhesion, besides inducing cell proliferation and upregulating gene expression related to tissue regeneration. Incorporation of multiwalled carbon nanotubes into PLA fibers has been reported to increase the mechanical properties of the scaffold, making them even more suitable for tissue engineering applications. Ideally, scaffolds should be degraded simultaneously with tissue growth. Hydration and swelling are factors related to scaffold degradation. Hydration would negatively impact the mechanical properties since PLA shows hydrolytic degradation. Water absorption critically affects the catalysis and allowance of the hydrolysis reactions. Moreover, either mass transport and chemical reactions are influenced by confined water, which is an unexplored subject for PLA micro- and nanoporous fibers. Here, we probe and investigate confined water onto highly porous PLA microfibers containing few amounts of incorporated carbon nanotubes by Fourier transform infrared (FTIR) spectroscopy. A hydrostatic pressure was applied to the fibers to enhance the intermolecular interactions between water molecules and C=O groups from polyester bonds, which were evaluated over the wavenumber between 1600 and 2000 cm-1. The analysis of temperature dependence of FTIR spectra indicated the presence of confined water which is characterized by a non-Arrhenius to Arrhenius crossover at T0 = 190 K for 1716 and 1817 cm-1 carbonyl bands of PLA. These bands are sensitive to a hydrogen bond network of confined water. The relevance of our finding relies on the challenge detecting confined water in hydrophobic cavities as in the PLA one. To the best of our knowledge, we present the first report referring the presence of confined water in a hydrophobic scaffold as PLA for tissue engineering. Our findings can provide new opportunities to understand the role of confined water in tissue engineering applications. For instance, we argue that PLA degradation may be affected the most by confined water. PLA degradation involves hydrolytic and enzymatic degradation reactions, which can both be sensitive to changes in water properties.

Heterogeneity of Micro- and Nanopore Structure of Lacustrine Shales with Complex Lamina Structure

Thin sections, AIM-SEM, MICP, and nitrogen adsorption were performed on laminated and layered shales to characterize their complex pore and fracture structure. Combining the MICP model with the FHH model, this work proposes a new fractal method for lacustrine shales with complex lamina structure. The fractal characteristics presented four zones, representing the heterogeneity of fractures, macropores, mesopores, and micropores. The pores and fractures of shale have strong heterogeneity. Laminated shale has strong heterogeneity in mesopores and moderate heterogeneity in micropores. Layered shale has strong heterogeneity in fractures and moderate heterogeneity in micropores. The lamina structure and content of organic and mineral composition has a great influence on heterogeneity. The mineral laminae in laminated shale change frequently; lamellation fractures are mainly developed, and the structures are similar. Layered shales develop fractures between layers and structural fractures; the structural differences are significant. Macropores are mostly interparticle pores between quarts with similar structures. The wider lamina thickness of layered shale provides sufficient crystallization space for minerals, so the mesopores of layered shale are more homogeneous. Micropores are less developed, mainly consisting of intraparticle pores between clay minerals, which are complex but similar in structure in the two types of shale. The heterogeneity of mesopores and micropores is not conducive to hydrocarbon migration. Fractures and macropores need to be connected with meso–micropores to form a transport system. So, mesopores and micropores play decisive roles in hydrocarbon migration. Based on the above understanding, this paper points out that hydrocarbon in laminated shale with more carbonate minerals and a high thermal evolution degree has better availability.

In situ fabrication of transition metal phosphide tree-like nanostructure for energy-saving hydrogen production coupled via urea oxidation reaction

Substituting the Oxygen Evolution Reaction (OER) with the Urea Oxidation Reaction (UOR) which is a thermodynamically more favorable option, has paved the way for the production of energy-saving hydrogen as well as the purification of urea-reach waste water. In this study, a nanostructured, porous and active Ni-Cu-Mn-P electrode was created using the dynamic hydrogen bubble template (DHBT) process in different conditions. The fabricated electrodes were utilized as bi-functional electrodes for both the HER and UOR processes. The electrochemical results displayed that the Ni-Cu-Mn-P (which synthesized at current density of 2 A.cm−2) requires only 84 mV overpotential to achieve a current density of 10 mA.cm−2, in HER process, and the necessary potential value for the UOR is only 1.30 V vs RHE. Also, the favorable electrocatalytic stability for industrial applications was also confirmed. The Ni-Cu-Mn-P electrode also demonstrated satisfactory performance in the overall urea electrolysis process and the cell voltage was 1.40 V to generate 10 mA.cm−2. The excellent performance of the electrode was due to the hierarchical porous nanostructure with high active surface area and also the synergistic effect between the elements. This study introduces an effective catalyst design for energy-saving hydrogen production.

A novel algorithm for asphaltene precipitation modeling in shale reservoirs with the consideration of capillary pressure during the CCUS processes

Tight and shale reservoirs have markedly expanded their role in global oil and gas production. However, the overall recovery from these reservoirs is suboptimal, leaving much of the shale oil unrecovered. CO2 flooding is a promising enhanced oil recovery (EOR) technique that can improve oil extraction and simultaneously facilitate carbon capture, utilization, and storage (CCUS). However, this method presents challenges, notably the precipitation and deposition of asphaltene, which risks plugging the nanoporous structure characteristic of shale reservoirs. Given that the nanopore sizes in these reservoirs align closely with asphaltene particle dimensions, the risk of pore and throat blockages during gas injection is pronounced. Although various asphaltene precipitation models have been proposed, there is still a lack of robust algorithms accounting for the substantial influence of capillary pressure on asphaltene precipitation in these nanopores. In this study, a novel three-phase vapor–liquid-asphaltene equilibrium calculation algorithm coupled with capillary effect is developed. The algorithm is first validated by comparing with the experimental data of the Px phase diagram and asphaltene precipitation amount. The validated algorithm is then used to conduct example calculations to demonstrate the robustness of the new algorithm and to examine the impact of capillarity on the three-phase vapor–liquid-solid (VLS) equilibria. Computation results show that capillary pressures in nanopores substantially modify the three-phase VLS equilibria, causing shifts in saturation pressure and influencing asphaltene precipitation. Generally, asphaltene precipitation in nanopores occurs at a lower pressure and gas injection concentration. The smaller pore sizes intensify these effects, but the impact diminishes as pressure increases. Additionally, the gas composition also greatly affects asphaltene precipitation. The results reveal that this new algorithm is robust across different conditions, offering an innovative approach that reliably predicts asphaltene precipitation considering the effect of capillary pressures, paving the way for improved EOR and CCUS in shale reservoirs.

Selective gas detection using phase change material infused photonic crystal

A photonic crystal-based optical gas detector is proposed, incorporating phase change material (PCM) to modulate the sensing properties. The multi-gas detection process is designed in the range of 650 nm to 2500 nm. Ge2Sb2Te5 (GST) is employed as a phase change material with significant optical property variations. It can exist in two self-sustaining, bi-stable phases: a crystalline GST (CGST) and an amorphous GST (AGST). The dielectrics (i.e., Si, SiO2, GST, and Au) are used in various combinations, such as Au-Si, Au-Si-SiO2, Au-GST-SiO2, and GST-Au. Plane light waves are used to model the nanoporous structures over a broad wavelength range (650 nm to 2500 nm). The optical spectral response of the structures, including the reflectivity spectrum, power absorption spectrum, and electric field distribution, is investigated by varying the GST thickness, dimension, and geometry of the nanoholes. Liquid ammonia has the highest selectivity of any gas from 650 nm to 1000 nm, at about 29%, whereas carbon monoxide has the maximum sensitivity of 32%. The interchanging of layers increases the sensitivity of all the gases. With a sensitivity and selectivity of 78% and 40%, respectively, carbon monoxide exhibits the greatest values.