Hierarchical Porous Structure Research Articles

Zeolite‐Based “Particle Board” Membranes for Rapid and Selective Hydrogen Permeation

AbstractZeolites, with their well‐defined pore sizes and outstanding stability, are regarded as the quintessential material for precise molecular separation tasks. However, the leap from easily produced zeolite powders to synthesizing free‐standing zeolite membranes, which can fully leverage their ordered porosity, presents substantial technical hurdles. Addressing this challenge, this study introduces polymers of intrinsic microporosity (PIM‐1) as adhesives through a wrapping‐compression method for the facile fabrication of high‐performance and free‐standing zeolite (FAU) “particle board” membranes. The 3D tomogram reconstruction from the focused ion beam‐scanning electron microscope images reveals the “particle board” membranes exhibit hierarchical porous structures. The non‐interconnecting macropores between zeolite particles facilitate the rapid H2 permeation, and the zeolites’ ordered micropores sieve the gas molecules. The optimized FAU@PIM‐1 free‐standing membrane with hierarchically pore structures demonstrated hydrogen permeance (2240 GPU) alongside H2/CH4 selectivity (31.68) for mixed gas and maintained this performance level under pressure ranges from 1.2 to 4.0 bar and over protracted operational periods (up to 3200 h). Meanwhile, EMT and MFI‐type zeolites have also been successfully applied to validate the versatility of this method, demonstrating its widespread potential for the fabrication of various free‐standing zeolite membranes.

Defect Passivation of Mn2+-Doped CsPbX3(X=Cl,Br) Perovskite Nanocrystals as Electrocatalyst for Overall Water Splitting.

Mn doping has been used to improve the physical chemistry of lead halide perovskite nanocrystals such as CsPbX3, where X is a halogen ion. In this paper, a two-phase method for Mn-doped CsPbX3 nanosheets (where X=Br, Cl), namely water-hexane system, is reported. Compared to conventional catalyst arrays, the band gap of CsPbBr3 nanocrystalline is easily tuned, the carrier diffusion distance is remote, the band edge position of the band structure is favorable for a wide range of electrocatalytic redox reactions, and the catalytic active site is maximally exposed, providing a larger electrolyte contact area. The porous hierarchical structure also accelerates the release of hydrogen bubbles. The results showed that the optimized Mn : CsPbBr3 catalyst exhibited excellent electrolytic performance of aquatic hydrogen in alkaline electrolyte (1 mol/L KOH). The overpotentials of the oxygen evolution reaction (OER) at the current densities of 10 and 100 mA cm-2 are only 114.4 and 505.4 mV, respectively, with a Tafel slope of 43 mV dec-1. At a current density of 10 mA cm-2, the excess potential required for the hydrogen evolution reaction (HER) is 158.6 mV and it exhibits excellent electrochemical stability. The Mn : CsPbBr3 nanocrystalline consists of two electrodes for hydrolysis of water, requiring only a voltage of 1.45 V. This provides implications for the optimization of electrocatalysts in alkaline electrolytes with the aim of developing next generation 2D electrocatalysts for overall water splitting.

Multifunctional molecular precursor with tunable nano-microarchitecture enables exceptional electromagnetic waves absorption

Multi-component carbon is a promising candidate for electromagnetic wave (EMW) absorption materials. However, complex and non-green preparation process with low atomic utilization efficiency compromises the merits of carbon materials. Additionally, enhancing the electromagnetic wave absorption (EMWA) is highly desirable. To face the challenge, a multifunctional molecular precursor (DQSDCI) has been developed, characterized by high atom utilization efficiency (high char yield), abundant in-situ nitrogen doping, multi-sites for composite of nano-materials (e.g. CNT) or metal ion (e.g. iron) and green preparation (water solubility). The multi-component carbons derived from DQSDCI, featuring adjustable nanostructures (nanoribbons or nanosheets) and modifiable porosity, demonstrate outstanding EMWA. The multicomponent carbon of DQSDCI, iron and CNT (DQSDCI-Fe-CNT-700) demonstrated a minimum reflection loss (RLmin) of −69.57 dB and a maximum effective absorption bandwidth (EABmax) of 5.7 GHz at about 2 mm thickness, covering a wide frequency range (4–18 GHz) by controlling the thickness between 1 and 5 mm. Moreover, simulation results indicated that the derived nanosheet is very promising application for aircraft stealth in a monostatic radar system. Abundant in-situ N doping, uniform distribution of MWCNT and ferromagnetic nanoparticles, hierarchical pore structures and various heterogeneous interfaces can synergistically improve the EMW attenuation ability by forming optimal impedance matching and multi-polarization loss.

Ce-doped NiFe-layered-double-hydroxide hierarchical nanocomposite and metal/imidazolate framework carbon nanotube nanocomposite: A bifunctional material for OER electrocatalyst and supercapacitor electrode applications

The development of nanocomposites as electrocatalysts with low cost and high efficiency for OER and as electrode material enhancing the electrochemical performance of supercapacitors are the most popular investigations in this field. Herein, a new bifunctional composite including Ce-doped NiFe-LDH Nanosheets and ZIF-derived carbon base incorporating neodymium and Fe into the structure of Zeolitic Imidazolate Framework is proposed and the construction was through entering Fe-ZIF8@Nd-ZIF67 into the structure of NiFeCe-LDH in different ratios of 10, 20 and 30 %. Various physical and electrochemical tests were conducted to evaluate the nanocomposites. Results indicated that the composite presented a hierarchical porous structure and exhibited outstanding performance for OER and supercapacitor applications. According to the results, the 30 % composite of NiFeCe-LDH/ Fe-ZIF8@Nd-ZIF67 exhibits a superior onset overpotential of 170 mV and an overpotential of 300 mV at a current density of 10 mA·cm−2. Besides, it shows an excellent specific capacitance of 345.36 (F.g−1) at 1 A.g−1. Hence, the synthesized nanocomposite demonstrated outstanding performance in both OER and supercapacitor applications.

Fabrication of hierarchically porous trabecular bone replicas via 3D printing with high internal phase emulsions (HIPEs)

Combining emulsion templating with additive manufacturing enables the production of inherently porous scaffolds with multiscale porosity. This approach incorporates interconnected porous materials, providing a structure that supports cell ingrowth. However, 3D printing hierarchical porous structures that combine semi-micropores and micropores remains a challenging task. Previous studies have demonstrated that using a carefully adjusted combination of light absorbers and photoinitiators in the resin can produce open surface porosity, sponge-like internal structures, and a printing resolution of about 150µm. In this study, we explored how varying concentrations of tartrazine (0, 0.02, 0.04, and 0.08 wt%) as a light absorber affect the porous structure of acrylate-based polymerized medium internal phase emulsions fabricated via vat photopolymerization. Given the importance of a porous and interconnected structure for tissue engineering and regenerative medicine, we tested cell behavior on these 3D-printed disk samples using MG-63 cells, examining metabolic activity, adhesion, and morphology. The 0.08 wt% tartrazine-containing 3D-printed sample (008 T) demonstrated the best cell proliferation and adhesion. To show that this high internal phase emulsion (HIPE) resin can be used to create complex structures for biomedical applications, we 3D-printed trabecular bone structures based on microCT imaging. These structures were further evaluated for cell behavior and migration, followed by microCT analysis after 60 days of cell culture. This research demonstrates that HIPEs can be used as a resin to print trabecular bone mimics using additive manufacturing, which could be further developed for lab-on-a-chip models of healthy and diseased bone.

Deep Eutectic Solvent and Molten Salt-Assisted Construction of Wheat Straw-Derived N/O Co-Doped Porous Carbon for Flexible Zinc-Air Batteries.

As a common biomass resource, wheat straw is gradually being derived as carbon materials for oxygen reduction reaction (ORR) in zinc-air batteries (ZABs). Herein, the wheat straw-derived carbon was prepared by ball milling and pyrolysis using deep eutectic solvent (DES) as the medium, which avoided the cumbersome procedures. The hydrogen bond of DES was utilized to reconstructed into a hydrogen bond network structure between DES and lignin/cellulose/hemicellulose of wheat straw. The hydrogen bond network structure was converted into N/O co-doped porous carbon (N/O-WSPC) with abundant N/O co-doped sites after high-temperature pyrolysis. Meanwhile, KHCO3 was employed to further generate hierarchical pore structures and increase the specific surface area of the N/O-WSPC. The N/O co-doped sites provided intrinsic ORR activity, while the porous structure facilitates the mass transfer effect. Therefore, the N/O-WSPC exhibited a half-wave potential of 0.87 V (vs. RHE) and a limiting current density of 5.98 mA cm-2 for ORR. The N/O-WSPC-based flexible ZAB displayed an energy density of 652.23 Wh kg-1 and a charging-discharging cycle duration for over 19 h. The DES-assisted strategy facilitates the sustainable and efficient application of wheat straw-derived carbon materials in energy storage and conversion devices.

The effect of carbon supports on the electrocatalytic performance of Ni-N-C catalysts for CO2 reduction to CO

Carbon-supported nickel and nitrogen co-doped (Ni-N-C) catalysts have been extensively studied as selective and active catalysts for CO2 electroreduction to CO. Most studies have focused on adjusting the coordination structure of Ni-Nx active sites, while the impact of the carbon supports has often been overlooked. In this study, a series of Ni-N-C catalysts on different carbon supports, including carbon black (CB), multi-walled carbon nanotubes (CNT), and activated nitrogen-doped biochar (ANBC), were synthesized using a ligand-mediated method. The effect of the carbon support on the electrocatalytic performance for CO2 reduction was investigated at both low current densities, in a H-cell, and high current densities, in a MEA electrolyzer. All of the prepared Ni-N-C catalysts show good faradaic efficiencies (FE) toward CO production (up to ~90%), however, the onset potentials and partial current densities for CO production vary greatly. The textural properties of the carbon support and the distribution of Ni-Nx active sites on the carbon support are demonstrated as the main factors behind the performance differences. In particular, hierarchical porous structures with large specific surface area are helpful to facilitate mass transport and improve the dispersion of active sites, which allows for a better CO2 reduction performance of Ni-N-ANBC compared to Ni-N-CB and Ni-N-CNT. This study demonstrates the importance of the carbon support for Ni-N-C catalysts and provides new insights into the design of efficient Ni-N-C catalysts for the CO2RR.

Layered double hydroxides-derived CoNi alloy nanoparticles encapsulated by porous N-doped carbon nanofibers as efficient methanol electrocatalysts for alkaline direct methanol fuel cells

The exploration of inexpensive electrocatalysts possessing high activity and increased stability to replace precious metal catalysts in the methanol oxidation reaction (MOR) is highly desirable for alkaline direct methanol fuel cells (ADMFCs). This study presents a novel approach to synthesize layered double hydroxides (LDHs)-derived CoNi alloy nanoparticles confined within porous N-doped carbon nanofibers (CoNi@NCNFs) via facile electrospinning and pyrolysis for methanol electrooxidation.The one-dimensional N-doped carbon nanofibers could effectively prevent nanoparticle agglomeration during the pyrolysis of LDH precursors. The optimized CoNi@NCNF3-900 composite exhibits exceptional catalytic activity (80.3mAcm−2) for MOR in alkaline solution, attributed to its hierarchical porous structure, high surface area, and abundant accessible active sites. Furthermore, the catalyst demonstrates competitive electrocatalytic stability, retaining over 90% of its initial current density after 1000 consecutive cyclic voltammetry (CV) cycles. Notably, a single-cell ADMFC assembled with CoNi@NCNF3-900 as the anode catalyst achieves a promising maximum power density of 29.5mWcm−2, highlighting the potential of CoNi@NCNF3-900 for application in DMFC technology and clean energy sources.

Synergistic effect of Fe/Zr dual doping endows hydrophilic spinel-structured H4Ti5O12 ion sieves for efficient lithium extraction from liquid resources

The practical application of spinel-structured H4Ti5O12(HTO) lithium-ion sieves (LISs) is hampered by their poor adsorption properties and recyclability. Within this research, the surface properties and internal structure of lithium-ion sieve (LIS) materials were modulated by co-doping Fe and Zr metal ions to enhance their adsorption properties. The results show that Fe and Zr have been successfully introduced to the LIS lattice, increasing Li-O bond length of position 8a and O2− content. The synthesized H4Ti4.77Fe0.2Zr0.03O12 (HTFZO-II) LIS was made up of evenly distributed nanosheets layered on top of one another to create an open laminar structure, which possesses a hydrophilic surface (contact angle: 17.8°), a high surface area (95.89 m2/g), and hierarchical porous structure. Compared with the undoped HTO, the HTFZO-II LISs enjoy a high capacity for Li+ adsorption (28.72 mg/g), a strong cycling stability (Ti4+ dissolving loss: 0.12 %), and a fast reaching of the equilibrium in adsorption (adsorption equilibrium: 4 h). Theoretical calculation of DFT shows that Li(H2O)4+ on HTFZO-II and HTO dehydration were partially dehydrated into Li(H2O)+. The energy required for the dehydration of Li(H2O)4+ on HTFZO-II is lower than that on undoped HTO, indicating that metal ion doping modification was beneficial for the dehydration of hydrated lithium ions on the adsorbent surface, thereby accelerating the exchange reaction between H+ and dehydrated Li+ ions. This study reveals the key role of the synergistic effect of multi-element co-doping in enhancing the adsorption performance and structural stability of LISs.

Hierarchical porous carbon spheres using nano-ZnO as a template to remove benzene and ethyl acetate

The treatment of volatile organic compounds emitted from the paint and coatings industry is a challenge. In this study, porous carbon spheres (PCSs) with a diameter of about 1mm were successfully prepared via the phase inversion followed by charring with nano-ZnO as the template to adsorb VOCs. Nano-ZnO prepared in situ was adapted to tailor the structure and chemical properties of PCSs, and commercial nano-ZnO was used for comparison. The resultant PCSs possessed a high surface area and favorable hierarchical porous structure. Adsorption of benzene and ethyl acetate from the paint and coatings industry can be used to evaluate the adsorption properties of PCS. Due to the doping of different amount of in-situ nano-ZnO, the specific surface area increased and the pore size decreased, which accelerated the mass transfer and had a good adsorption effect. In particular, the adsorption capacity of PCSs-2 to benzene reached 459.6mg/g. At the same time, due to the abundance of oxygen-containing functional groups on the PCSs surface, hydrogen bonds could be formed with polar molecules, thus achieving a good adsorption effect on polar VOCs. The simultaneous adsorption mechanism of benzene and ethyl acetate was also defined. These results suggested that PCS would be ideal for the removal of VOCs from the paint and coatings industry.

Ultra-lightweight asymmetric hierarchical porous structure for high-efficiency absorption-dominated electromagnetic interference shielding

In this work, ultra-lightweight composite aerogels with a hierarchical pore structure consisting of hollow Fe3O4 microspheres (∼250 nm), hollow MXene microspheres (∼580 nm) and pores (10∼40 μm) in polyimide (PI) aerogel are developed through directional freezing, followed by freeze drying and thermal annealing. The composite aerogels exhibit a distinct asymmetric structure, with a top Fe3O4/PI aerogel layer designed for impedance matching and a bottom MXene/PI aerogel layer aimed at enhancing attenuation. This deliberate structure design not only reduces the density of the composite aerogels but also greatly enhances their absorption of electromagnetic waves. The composite aerogel demonstrates an impressive X-band EMI SE of 69.7 dB, a remarkable absorption coefficient (A) of 0.73, and an excellent surface-specific SE (SE divided by material density and thickness) of 13352 dB cm2 g-1, achieved at a density of just 0.034 g/cm³. Moreover, the composite aerogel exhibits outstanding stability in compression and shielding performance. Following 100 cycles of compression, the compressive strength remains at 94.9% of the initial compressive strength (98 kPa), and its EMI SE maintains 68.5 dB with a retention rate of 98.2%. Additionally, the composite aerogel presents outstanding thermal insulation (0.046 W m-1 K-1) and thermal resistance (initial decomposition temperature > 500 °C). This work provides novel insights into the design and fabrication of ultra-lightweight and absorption-dominated EMI shielding materials.

A nanoporous nickel–iron alloy seamlessly anchored into hierarchical porous nickel for efficient and extremely stable water splitting

The development of a robust, low-cost electrode for electrochemical water splitting is a challenging, but essential task for realizing hydrogen production under industrial conditions. Here, we seamlessly anchor nanoporous nickel–iron into a hierarchical porous nickel foam (npNi–Fe/HPNF) by a designed gaseous oxidation–reduction engineering for a commercial nickel foam. The three-dimensional hierarchical porous structure considerably enhances the specific surface area of the electrode, yielding abundant electrocatalytic sites that promote the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Moreover, owing to its mechanically robust, seamlessly anchored architecture, and remarkable superhydrophilicity/superaerophobicity, the electrolyzer composed of self-standing npNi–Fe/HPNF and its electro-activation derivative displays a current density of 10 mA cm−2 at 1.54 V, ultralong durability of more than 2000 h at 500 mA cm−2 in a 1 M KOH electrolyte, and high performance of 2 V at 1 A cm−2 in a quasi-industrial environment (5 M KOH and 70 °C), outperforming most alkaline electrolyzers based on state-of-the-art electrodes. Exceptional electrochemical performance and the ability to be prepared at a large scale (2500 cm2) make npNi–Fe/HPNF a promising candidate for industrial water splitting applications.

Determination of seven phenoxy carboxylic acid herbicides in water using dispersive solid phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry based on metal-organic framework composite aerogel

Phenoxy carboxylic acid herbicides (PCAs) are difficult to degrade and, thus, pose significant threats to the environment and human health. The limit for 2,4-dichlorophenoxyacetic acid is 30 μg/L in China's standards for drinking water quality, 70 μg/L in the United States' drinking water standards, and 30 μg/L in the World Health Organization's guidelines for drinking water quality. Therefore, the development of an effective detection method for trace PCAs in water is a crucial endeavor. Metal-organic frameworks (MOFs) are novel porous materials that possess advantages such as a large specific surface area, adjustable pore size, and abundant active sites. They exhibit excellent adsorption capability for various compounds. However, the applications of MOFs as adsorbents are limited. For example, the process of isolating powdered MOFs from aqueous solutions is laborious, and microporous MOFs exhibit limited surface affinity, which decreases their mass transfer efficiency in the liquid phase. MOF crystals can be embedded in a substrate to overcome these limitations. Aerogels are obtained by drying hydrogels, which are hydrophilic polymers with a three-dimensional crosslinked network structure. Spongy aerogel materials exhibit unique structural properties such as high porosity, large pore volume, ultralow density, and easy tailorability. When MOFs are combined with an aerogel, their efficient and selective adsorption properties are preserved. In addition, MOF aerogels exhibit a hierarchical porous structure, which enhances the affinity and mass transfer efficiency of the MOF for target molecules. At present, MOF aerogels are primarily prepared by freeze-drying or using supercritical carbon dioxide. These drying processes require significant amounts of energy and time. Hence, the development of greener and more efficient methods to prepare skeleton aerogels is urgently needed. In this study, we prepared an environment-friendly aerogel at ambient temperature and pressure without the use of specialized drying equipment. This ambient-dried MOF composite aerogel was then used for the dispersive solid phase extraction (DSPE) of seven PCAs from environmental water, followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The key parameters affecting the efficiency of DSPE, including the extraction conditions, ratio of MIL-101(Fe)-NH2 to sodium alginate, pH of the aqueous samples, extraction time, ionic strength (salinity), and elution conditions, such as the elution solvent ratio, elution time, and elution volume, were investigated to obtain optimal extraction efficiency. The adsorbent could adsorb the target contaminants within 12 min, and the analytes could be completely desorbed within 30 s by elution with 4 mL of 1.5% (v/v) formic acid in methanol solution. The water samples could be analyzed without pH adjustment. The main adsorption mechanisms were electrostatic interactions and π-π conjugation. Thus, a new method based on MOF aerogels coupled with UHPLC-MS/MS was developed for the determination of the seven PCA residues in water. The calibration curves for the seven PCAs showed good linearity (r2≥0.9986), with limits of detection (LODs) and quantification (LOQs) ranging from 0.30 to 1.52 ng/L and from 1.00 to 5.00 ng/L, respectively. Good intra- and inter-day precision values of 6.5%-17.1% and 7.4%-19.4%, respectively, were achieved under low (8 ng/L), medium (80 ng/L), and high (800 ng/L) spiking levels. The developed method was applied to the detection of PCAs in surface water, seawater, and waste leachate, and the detected mass concentrations ranged from 0.6 to 19.3 ng/L. Spiked recovery experiments were conducted at mass concentrations of 8, 80, and 800 ng/L, and the recoveries ranged from 61.7% to 120.3%. The proposed method demonstrates good sensitivity, precision, and accuracy, and has potential applications in the detection of trace PCAs in environmental water.

Porous activated carbon electrodes derived from Eleusine coracana biowaste in electric double layer capacitors: Nanoarchitectonics and performance

The development of high-performance supercapacitors from biowaste is crucial for advancing sustainable and renewable energy storage technologies. In this study, we report the fabrication of electrodes for high-performance supercapacitors using porous carbon derived from red millet (Eleusine coracana) straw. Porous carbon was synthesized via a two-step chemical activation process using KOH, resulting in a hierarchical pore structure comprising macro-, meso-, and micropores. The red millet-based porous carbon electrodes, assembled in a two-electrode symmetrical supercapacitor, exhibited a specific capacitance of 68 Fg⁻1 at a current density of 0.5 Ag⁻1 in a 1 M Na₂SO₄ aqueous electrolyte. At a mass loading of 5 mg per electrode, the system demonstrated a specific capacitance of 300 Fg⁻1 at 1 Ag⁻1, with an energy density of 9.1 Whkg⁻1 and a power density of 1.86 kWkg⁻1, as determined from galvanostatic charge-discharge measurements. Additionally, the supercapacitor showed excellent cyclic stability, retaining 98.78% of its initial capacitance after 5000 cycles at 10 Ag⁻1. These findings highlight the potential of porous carbon derived from agricultural biowaste for scalable applications in electric double-layer capacitors.

Enhanced mass transport on single-atom Ni-N-C catalysts with hierarchical pore structures for efficient CO2 electroreduction

Enhanced mass transport on single-atom Ni-N-C catalysts with hierarchical pore structures for efficient CO2 electroreduction

Nitrogen and sulfur co-doped porous carbon obtained from direct carbonization of a renewable biomass for counter electrode of efficient dye-sensitized solar cells

It is highly necessary to fabricate cost-effective counter electrode for promoting the development and practical deployment of dye-sensitized solar cells (DSSCs). Herein, nitrogen and sulfur co-doped porous carbon (NSPC) is prepared through directly carbonizing a renewable biomass, Eupatorium fortunei Turcz., and used as an alternative to expensive Pt to fabricate low-cost counter electrode for high-performance DSSCs. Scanning electron microscopy and N2 adsorption analyses demonstrate that the obtained carbon sample displays a hierarchical pore structure containing macropore channels and well-developed mesopores formed on the wall of macropore channels. X-ray photoelectron spectroscopy measurements suggest that nitrogen and sulfur atoms are doped in the framework of as-prepared carbon sample. These favorable characteristics endow the obtained NSPC counter electrode with a superior electrocatalytic performance. Consequently, the assembled DSSC with NSPC counter electrode shows an efficiency of 8.25%, nearly matching the efficiency of the cell with conventional Pt counter electrode.

Hierarchical structural design of cobalt sulphide nanoparticles/nickel sulphide for high-performance supercapacitors

Metal-organic framework (MOF) materials have become increasingly attractive in supercapacitor electrode research because of their regular crystal topology and tunable pore distribution. The strategy for the synthesis of the Ni3S4/Co3S4 electrode material with a layered structure was successfully devised using the layered Ni-MOF as a template and precursor. The characterisation techniques of XRD, FTIR, XPS, SEM, TEM and BET have provided confirmation of the assertion that the Ni3S4/Co3S4 composites exhibit an advanced hierarchical pore structure and considerable specific surface area. The specific capacity of the Ni3S4/Co3S4 composite is as high as 122.8 mAh g−1, and it can still maintain 72.6 % of the specific capacity after 3,000 cycles. Furthermore, the SEM morphology remains largely unchanged after cycling, which demonstrates excellent stability. Moreover, honeycomb-shape porous carbon (N-HAPC) with ultra-high specific surface area was selected as negative electrode material to fabricate a novel hybrid supercapacitor (Ni3S4/Co3S4//N-HAPC), which exhibits a broad operational voltage range of 1.6 V and superior energy density of 28.6 Wh kg−1. Simultaneously, HSCs exhibited remarkable charge-discharge stability, exhibiting a mere 17.2 % decline in capacitance stability following 7,000 GCD cycles. The combination of two Ni3S4/Co3S4//N-HAPC HSCs in series has been demonstrated to be capable of illuminating a small LED lamp, indicating the potential for their use in practical applications. Furthermore, this approach offers a novel strategy for the structural design of MOF-like materials.

Transparent and Flexible Hierarchical Porous Structure of Polyvinyl Alcohol Aerogel: A Microstructure Study.

Aerogels have gained increasing attention due to their unique properties since their introduction in 1932. Silica aerogel, one of the earliest and most advanced types, is known for its high transparency and excellent thermal insulation. However, its internal pearl-like structure makes it extremely brittle, which limits its practical applications. To address this, through multiple refinements in formulation and production techniques, we developed a novel Polyvinyl Alcohol (PVA) aerogel using an innovative one-step standing method. This method significantly reduces the gelling time compared to the freeze-thaw method and eliminates the need for refrigeration, making it a more environmentally friendly and sustainable process. The resulting one-step standing PVA aerogel features a hierarchical porous structure, remarkable transparency, improved strength, and enhanced thermal insulation. Mechanical tests demonstrated that the PVA aerogel produced by the one-step standing method exhibited a significantly higher Young's modulus of 4.2596 MPa, surpassing that of silica, copper nanowire (Cu NM), and graphene aerogels. Additional tests, including transmittance and thermal analysis, further confirmed that the one-step standing PVA aerogel excels in both transparency and thermal insulation. This combination of improved mechanical performance and light transmission opens novel potential applications, such as drug delivery systems, where the aerogel's pore structure can store drugs while maintaining strength and transparency.

Mg and Fe co-loaded biochar prepared by microwave-synergized K2FeO4 of marine biomass for efficient CO2 capture: Performance assessment and mechanism exploration

To overcome the limitations of complex preparation and suboptimal performance of CO2 adsorbents, the present work synthesized a polymetallic oxide-loaded biochar (MgO·FeOx@biochar) with good performance in one step using a green and simple method of microwave-synergized K2FeO4. MgO·FeOx@biochar-700–10-0.1 with a hierarchical porous structure, abundant adsorption sites and well-distributed basic sites was obtained by optimizing the preparation parameters, which had a good CO2 trapping performance of 4.92 mol/kg with a retention rate of 83.01 % over 20 cycles, and exhibited good selectivity for O2 and N2. CO2 capture by MgO·FeOx@biochar was predominantly driven by chemical interaction between surface adsorption sites and CO2, supplemented by microporous filling. The adsorption kinetics revealed that the CO2 adsorption rate of MgO·FeOx@biochar was influenced by the combined effect of membrane diffusion resistance and intraparticle diffusion resistance. This study established a theoretical basis and technical insight for the environmentally friendly and efficient preparation of high-performance biochar-based CO2 adsorbents.

Achievements and Challenges in Surfactants-Assisted Synthesis of MOFs-Derived Transition Metal-Nitrogen-Carbon as a Highly Efficient Electrocatalyst for ORR, OER, and HER.

Metal-organic frameworks (MOFs) are excellent precursors for preparing transition metal and nitrogen co-doped carbon catalysts, which have been widely utilized in the field of electrocatalysis since their initial development. However, the original MOFs derived catalysts have been greatly limited in their development and application due to their disadvantages such as metal atom aggregation, structural collapse, and narrow pore channels. Recently, surfactants-assisted MOFs derived catalysts have attracted much attention from researchers due to their advantages such as hierarchical porous structure, increased specific surface area, and many exposed active sites. This review mainly focuses on the synthesis methods of surfactants-assisted MOFs derived catalysts and comprehensively introduces the action of surfactants in MOFs derived materials and the structure-activity relationship between the catalysts and the oxygen reduction reaction, oxygen evolution reaction, and hydrogen evolution reaction performance. Apparently, the aims of this review not only introduce the status of surfactants-assisted MOFs derived catalysts in the field of electrocatalysis but also contribute to the rational design and synthesis of MOFs derived catalysts for fuel cells, metal-air cells, and electrolysis of water toward hydrogen production.