3D Porous Framework Research Articles

Rapid foaming of dense MXene films induced by acid-base neutralization reaction

Transforming dense MXene (Ti3C2Tx) films into lightweight 3D porous frameworks is crucial for practical applications of 2D MXene materials. However, traditional foaming technologies may compromise the intrinsic properties of MXene films, such as foldability, which is essential for future applications. Here, we report an approach using a common acid-base neutralization reaction to rapidly foam MXene films. The acid solution triggers the generation of porous structures in alkalized MXene films, resulting in a 3D porous MXene film with good foldability, excellent absolute shielding efficiency (25,445 dB cm2 g−1), electrochemical capacitance, and infrared stealth properties. Furthermore, the acid-base neutralization reaction strategy can be applied to foam other 2D material films, such as graphene oxide, broadening the potential for developing innovative foaming modes of 2D materials. This work enhances our understanding of MXene film foaming and lays the foundation for further applications of MXenes.

Biowaste-derived oxygen-self-doped three-dimensional interconnected porous carbon for electrochemical supercapacitor applications

ABSTRACT Biowaste for producing a biomaterial is an inexpensive, profuse, widely available, and viable natural source and has been extensively investigated and applied in a wide range of research fields. In this work, jackfruit leaf waste as a biowaste source was utilized to prepare a three-dimensional (3D) interconnected porous carbon framework self-doped with oxygen by KOH impregnation, carbonization, and activation under a CO2 atmosphere. The as-prepared porous carbon has a 3D interconnected porous framework with a rich oxygen content of 36.82%, and high BET surface area of 455.687 m2 g−1 with a pore volume of 0.522 cm3 g−1. The 3D interconnected porous framework exhibits a high specific capacitance of 199 F g−1 with a maximum energy density of 27.64 Wh kg−1 at a power density of 99.60 W kg−1 at a sweep rate of 1 mV s−1 in a two-electrode setup. The correlation between structure and great performance of electrode materials is deeply studied. The great capacitive performance of porous carbon materials can be assigned to its 3D interconnected porous framework, high specific surface area, suitable pore size distributions, and advantageous heteroatom-doping, resulting in the rapid ion diffusion and sufficient charge storage along with the contributed pseudocapacitance behavior. Hence, the exciting results reveal an efficient, cost-effective, time-saving, and facile method to prepare 3D interconnected porous carbon frameworks self-doped with oxygen derived from natural biowaste sources for developing supercapacitor devices.

Robust chromophore-integrated MOFs as highly visible-white-light active and tunable size-selective photocatalysts towards benzothiazoles

Visible-light heterogeneous photocatalyst with high activity and selectivity is crucial for the development of organic transformations, but remains a formidable challenge. Herein, a simple and effective strategy was developed to integrate tetrazine moiety, a visible light active unit, into robust metal-organic frameworks (2D MOF-1(M), M = Co, Mn, Zn, and 3D MOF-2(Co)). MOF-1 series are isomorphous 2D porous frameworks, and MOF-2(Co) displays 3D porous framework. Interestingly, benefiting from the oxidative active species of O2•−, these MOFs all exhibit obviously highly enhanced photocatalytic activities toward the straightforward condensation of o-aminothiophenol and aromatic aldehydes at room temperature in EtOH under visible-white-light irradiation. Notably, compared to 3D MOF, the 2D layered MOF-1(Co) exhibited more excellent catalytic activity with a wide range of substrates possessing preeminent tolerance of steric hindrance. Most impressively, MOF-1(Co) can be recycled at least five times without significant loss of catalytic activity or crystallinity, exhibiting excellent stability and reusability. This study sheds light on the wide-ranging prospects of visible light active 2D MOFs as green photocatalysts for the preparation of fine chemicals

Highly Anisotropic Carbonized Wood as Electronic Materials for Electromagnetic Interference Shielding and Thermal Management

AbstractLightweight carbonized wood has a hierarchically 3D porous framework and orthotropic channels along the growth direction, which demonstrate great potential for multifunctional electronic materials. Herein, carbonized wood with outstanding electromagnetic interference (EMI) shielding effectiveness (SE), high thermal conductivity, and excellent Joule heating property is fabricated. It also exhibits a highly anisotropic EMI shielding performance in the cross‐ and tangential‐sections. In the tangential‐section, the shielding performance of carbonized wood is tuned by monitoring the angle between the wood grain and the electric field vibration direction of the electromagnetic waves, and the SE value ranges from 29 to 77 dB when the angle changes from 90° to 0°. Benefiting from the high SE obtained from structural optimization and the low density, carbonized balsa wood displays a high SSE (the ratio of SE to density) and SSE/t (the ratio of SSE to thickness) of 1069 dB cm3 g−1 and 3263 dB cm2 g−1, respectively. The thermal conductivity of carbonized wood is also angle‐dependent, which ranges from 0.865 to 1.897 W m−1 K−1. With the improvement in thermal conductivity, carbonized wood can be used as a heat sink material. Meanwhile, excellent Joule heating properties are achieved due to the effective conductive pathway in carbonized wood.

Tailoring Cr doped NiFeP nanoparticles embedded in 3D cellulose nanofibrils carbon architecture for efficient oxygen evolution reaction

Oxygen evolution reaction (OER) is considered the bottleneck that restricting the pace of electrocatalytic hydrogen production. Modulating structure and heterogeneous doping are essential approaches to effectively promote the electrocatalytic efficiency and stability. Herein, three-dimensional (3D) porous Cr doped NiFeP nanoparticles encapsulated in cellulose nanofibrils (CNF) carbon architecture (Cr–NiFeP/NC) with high-efficiency and durable OER performance was constructed. CNF played crucial role on the construction of 3D porous framework and promoting the OER performance significantly. Benefiting from the 3D porous structure, high specific surface area and exposed abundant active sites, the Cr–NiFeP/NC electrocatalyst displayed excellent OER performance, which the overpotential to deliver the current density of 10 mA cm−2 was only 249 mV with a Tafel slope of 51.2 mV dec−1 in 1.0 M KOH, outperforming the RuO2 and other reported electrocatalysts remarkably. In addition, the Cr–NiFeP/NC electrocatalyst exhibited outstanding stability, which the overpotential was only increased by 2.5% after 48 h chronopotential measurement to deliver a current density of 10 mA cm−2 with stable morphology and structure. This work demonstrated an integrated strategy of Cr doping and 3D porous structure modulating employed CNF as skeleton for the efficient and durable OER performance, providing a spark for hydrogen production by water splitting.

Porous corallite-like NiSe2/CNTs nanocomposite fabricated by a convenient one-step in-suit solid-phase synthesis method with high performance in both supercapacitor and sodium-ion battery

If the agglomeration problem can be well addressed, the solid-phase synthesis method would be evolved into an effective strategy for the preparation of transition metal-base energy storage materials with the merits of convenience, eco-friendliness, and cost-effectiveness. In this work, a convenient one-step in-suit solid-phase synthesis (ISPS) method is developed for the fabrication of a porous corallite-like NiSe2/CNTs nanocomposite. The porous 3D framework constructed by CNTs provides a high-conductivity substance for the loading of NiSe2 nanospheres to form a nanocomposite with high conductivity, loose porous morphology, and small NiSe2 size, resulting in a good performance in both supercapacitor (SC) and sodium-ion battery (SIB). A high specific capacity of 172.70 mAh g−1 is achieved at 1 A g−1 for the synthesized nanocomposite as an electrode material of SC, which value remains at 108.64 mAh g−1 at 20 A g−1. High specific energy (42.8 Wh kg−1 at 0.84 kW kg−1) and excellent cycle durability (100% capacity retention after 20,000 cycles) are exhibited by a hybrid supercapacitor device assembled with a hierarchical porous carbon. When used as the anode of SIB, the synthesized nanocomposite delivers a high reversible specific capacity of 415.8 mAh g−1 after 270 cycles at 100 mA g−1, which is retained at 330 mAh g−1 after 360 cycles at 2.0 A g−1. The outstanding performance of the synthesized nanocomposite in both SC and SIB demonstrates the great prospect of the proposed ISPS method in the synthesis of high-performance energy storage materials.

MOF‐Derived Materials Enabled Lithiophilic 3D Hosts for Lithium Metal Anode — A Review

Comprehensive SummaryThis work systematically reviews recent progresses in the applications of MOF‐derived materials modified 3D porous conductive framework as hosts for uniform lithium deposition in LMBs. A series of commonly used lithiophilic materials and several kinds of representative MOF‐derivation‐modified 3D hosts as lithium metal anode (LMA) are presented. Finally, the challenges and future development of employing MOF‐derived materials to modify the 3D porous conductive framework for LMA are included.

Flexible Organic Framework‐Modified Membranes for Osmotic Energy Harvesting

Comprehensive SummaryBioinspired membranes are advantageous in capturing the osmotic energy. However, the conventional hybrid membranes possess low harvesting power density due to their low interfacial ionic transport efficiency and high internal resistance. Herein, a new kind of hybrid membranes consisting of porous polymer and flexible organic frameworks was developed. The 3D porous framework enables ions to flux with high efficiency at the polymer‐framework interface, resulting in high osmotic energy harvesting efficiency. By systematically screening the pore size of the frameworks, the output power density as high as 5.7 W/m2 was achieved under 50‐fold KCl salinity gradient.

Highly Stable and Reusable 3D Graphene-Quinizarin Voltammetric pH Sensor

A simple pH sensor has been developed employing a 3D porous graphene framework blended with quinizarin. The performance of the fabricated sensor is tested via the square wave voltammetry technique by applying different buffer solutions and real samples. The peak potential of the designed electrode varies with the change in pH of solutions due to 2e−/2H+ transfer process of pH-dependent quinone/hydroquinone redox couple. For varying pH (1–13), the designed sensor has a sensitivity of 65.6 ± 0.4 mV/pH at 25 °C. Soil pH sensing is performed for different types of soil samples prepared using 1M KCl and 0.01M CaCl2 solutions with a potential shift of 63.5 ± 0.9 mV/pH and 57.9 ± 0.3 mV/pH, respectively. The 3D graphene-quinizarin pH sensing probe demonstrates negligible hysteresis (± 0.3 pH) and long-term stability (six months and more). In comparison to the commercial pH meter, the fabricated sensor shows a relative inaccuracy of less than 5%. Moreover, a single electrode could be used to detect the pH of multiple environments by mild rinsing with deionized water and is reusable for more than 500 cycles without significant potential drift. These low-cost and reusable pH-sensitive electrodes with linear Nernstian response are promising candidates for diverse pH-sensing applications.

Ultrathin Li-rich Li-Cu alloy anode capped with lithiophilic LiC6 headspace enabling stable cyclic performance

Li-rich dual-phase Li-Cu alloy is a promising candidate toward practical application of Li metal anode due to its in situ formed unique three-dimensional (3D) skeleton of electrochemical inert LiCux solid-solution phase. Since a thin layer of metallic Li phase appears on the surface of as-prepared Li-Cu alloy, the LiCux framework cannot regulate Li deposition efficiently in the first Li plating process. Herein, a lithiophilic LiC6 headspace is capped on the upper surface of the Li-Cu alloy, which can not only offer free space to accommodate Li deposition and maintain dimensional stability of the anode, but also provide abundant lithiophilic sites and guide Li deposition effectively. This unique bilayer architecture is fabricated via a facile thermal infiltration method, where the Li-Cu alloy layer with an ultrathin thickness around 40 μm occupies the bottom of a carbon paper (CP) sheet, and the upper part of this 3D porous framework is reserved as the headspace for Li storage. Notably, the molten Li can quickly convert these carbon fibers of the CP into lithiophilic LiC6 fibers while the CP is touched with the liquid Li. The synergetic effect between the LiC6 fibers framework and LiCux nanowires scaffold can ensure a uniform local electric field and stable Li metal deposition during cycling. As a consequence, the CP capped ultrathin Li-Cu alloy anode demonstrates excellent cycling stability and rate capability.

Ultrafine V2O5-anchored 3D N-doped carbon nanocomposite with augmented dual-enzyme mimetic activity for evaluating total antioxidant capacity

Total antioxidant capacity (TAC) can be evaluated by detecting the content of antioxidants, such as ascorbic acid, based on the enzyme-mimetic activity of nanomaterials. Herein, we fabricated a 3D-V2O5/NC nanocomposite using a self-templating strategy, which achieved ultrafine particles (∼2.5 nm), a porous carbon layer, large specific surface area (152.4 m2/g), N-doping and heterogeneous structure. The strong catalytic activity of 3D-V2O5/NC resulted from the integrated effect between the ultrafine structure of V2O5 nanoparticles and the 3D porous nitrogen-doped carbon framework, effectively increasing the number of active sites. This nanozyme presented a higher catalytic activity than its components or precursors in the nanocomposite (e.g., VN/NC, NC, V2O5, and VO2/g-C3N4). ROS scavenging experiments confirmed that the dual enzyme-like activity of 3D-V2O5/NC (catalase-like and oxidase-like) resulted from their co-participation of ‧O2−, h+ and ‧OH, among which ‧O2− played a crucial role in the catalytic color reaction. By virtue of the 3D-V2O5/NC nanoenzyme activity and TMB as a chromogenic substrate, the mixed system of 3D-V2O5/NC + TMB + H2O2 provided a low detection limit (0.03 μM) and suitable recovery (93.0–109.5%) for AA. Additionally, a smartphone-based colorimetric application was developed employing "Thing Identify" software to evaluate TAC in beverages. The colorimetric sensor and smartphone-detection platform provide a better or comparable analytical performance for TAC assessment in comparison to commercial ABTS test kits. The newly developed smartphone-based colorimetric platform presents several prominent advantageous, such as low cost, simple/rapid operation, and feasibility for outdoor use.

Superhydrophobicity‐mediated enhanced enzymatic kinetics and high‐performance bioassays

AbstractAs a typical superwettability behavior, superhydrophobicity can provide an appropriate strategy to enhance the mass transport in multiphase chemical reactions. In the oxidase‐based enzymatic reactions, the elaborately regulating of reactant oxygen are critical to the development of an oxidase‐based high‐performance biosensor. In solid–liquid diphase condition, however, the kinetics of oxidase‐catalyzed reactions is inhibited by delayed mass transport and poor solubility of oxygen. To address this limitation, the design of the solid–liquid–air triphase interface is proposed according to the binary cooperation of superhydrophobicity and hydrophilicity. On the triphase joint interface, oxygen required for the oxidase‐catalyzed reactions can diffuse directly to the reaction center from the air phase through the micro/nanostructured superhydrophobic substrate, thus improving the kinetics of the oxidase‐catalyzed reactions. In this minireview, we summarize recent advances in the fabrication of triphase reaction system based on different superhydrophobic substrate for oxidase‐based biosensors. Common substrates including fibrous network, nanowire arrays, 3D porous framework, and hollow sphere structures are outlined in categories.

Biologically Inspired Small Herbal Biomolecules and Biomass Carbon for High-Performance Supercapacitors

A hybrid system electrode composed of porous lignin-based graphitic carbon (PLGC) and small herbal biomolecules such as Rhein (RH) with abundant redox centers is demonstrated to increase the specific capacitance and cycle stability of biomass electrode materials. RH molecules with abundant anthraquinone content, derived from the rhubarb (Rheum palmatum L.) root extracts, are responsible for increasing energy storage capacity, whereas PLGC with continuous three-dimensional (3D) porous framework provides an effective platform for bulk charge transport corresponding to the RH redox process within the composite electrodes. The RH/PLGC composite electrodes exhibited exceptional specific capacitance values of 250.2 F g–1 at 1.0 A g–1, and meanwhile, the capacity fading was effectively suppressed using an RH-saturated electrolyte, indicating the excellent compatibility of this biomass-based electrode material and the corresponding redox-active biomolecule-saturated electrolyte for large-scale production. Furthermore, through the use of gel electrolyte (PVA/KOH/RH), the assembled symmetric biomass-based supercapacitors demonstrate the significant specific capacitance, operational stability >3000 cycles, and considerable energy density. The utilization of biomolecules with redox centers by elucidating the charge storage mechanism will enrich the efficient and green energy storage technologies.

Slow Magnetic Relaxation and Modulated Photoluminescent Emission of Coordination Polymer Based on 3-Amino-4-hydroxybenzoate Zn and Co Metal Ions

As a starting point, a new 3D porous framework with the {[CoL]·0.5DMF·H2O}n chemical formula (where L = 3-amino-4-hydroxybenzoate) is described. Its performance as a single molecule magnet was explored. The study of magnetic properties reveals that Co-MOF shows no frequency-fdependant alternating current (ac) signals under zero direct current (dc) magnetic field, whereas single-molecule magnet behaviour is achieved when CoII ions are diluted in a ZnII based matrix. Interestingly, this strategy renders a bifunctional [CoxZn1-xL]n material that is also characterized by a strong photoluminescent emitting capacity.

Structure and Properties of a Mixed-Ligand Co-MOF That Was Synthesized in Situ from a Single Imidazole–Pyridyl–Tetrazole Trifunctional Ligand

A mixed-ligand Co-MOF (SCNU-Z7) based on a new imidazole–pyridyl–tetrazole trifunctional ligand, 3-(imidazol-1-yl)-5-(tetrazol-5-yl) pyridine (HITP), was constructed using a solvothermal reaction. Single-crystal X-ray diffraction analysis revealed that in addition to HITP, the 5,5′-bis-(2H-tetrazol-5-yl)-[3,3′]bipyridinyl (H2BTBP) ligand obtained by the in situ reaction of HITP is also incorporated into the framework, thus generating a mixed-ligand metal–organic framework (MOF). SCNU-Z7 has a 3D porous framework with 1D channels along the c axis based on tetranuclear secondary building blocks and has a new highly (3,4,10)-connected network topology with the symbol (416·620·89)(43)2(44·62). SCNU-Z7 exhibits high stability in organic solvents but instability in water. Gas adsorption studies indicated that SCNU-Z7 can absorb CO2 more than N2. Magnetic studies indicate the existence of dominant antiferromagnetic interactions between Co(II) atoms. Due to porosity, Co(II) ions, nitrogen-rich conjugated aromatic rings, and uncoordinated nitrogen atoms in its framework, SCNU-Z7 can capture iodine in vapor with a capacity of 2.7 g/g. The strong interactions between the framework and the iodine molecules cause the amorphization of the framework, and approximately 60% of the adsorbed iodine molecules can be stably stored in the framework. This study provides a new possible route for obtaining mixed-ligand MOFs and provides a new example for stably capturing iodine in MOFs via amorphization.

Copper Foam-Supported CuxO@Fe2O3 Core–Shell Nanotubes: An Efficient Ozonation Catalyst for Degradation of Organic Pollutants

Copper foam (CF)-supported CuxO@Fe2O3 core–shell nanotubes (CF/CuxO@Fe2O3 NTs) were synthesized as a hybrid catalyst for heterogeneous catalytic ozonation (HCO). The hybrid catalyst exhibits high activity and excellent stability for the HCO of organic pollutants. The total organic carbon removal rates of methyl orange, ibuprofen, and nitrobenzene via HCO were 89, 82, and 88%, respectively, which are over 2 times higher than the corresponding values obtained without the catalyst. The hybrid catalyst also displays wide pH operation range, low metal leaching, easy separation from treated water, and excellent recyclability. We prove that large amounts of Lewis acid sites with medium acidity are created at the CuxO/Fe2O3 interface due to the synergic effect of CuxO and Fe2O3. These medium acid sites are the main active centers for the production of free hydroxyl radicals (•OH) and superoxide radicals (O2•– or HO2•) in neutral solution. Moreover, the 3D porous framework of the catalyst enables easy dispersion in and separation from water. This work develops a new strategy to design HCO catalysts by combining strong and weak Lewis acid oxides and also opens a new avenue for developing HCO catalysts on a 3D porous framework.

O-doping induced abundant active-sites in MoS2 nanosheets for propelling polysulfide conversion of Li-S batteries

The oxygen doped MoS2 nanosheets were in-situ grown into the three-dimensional (3D) porous graphene frameworks (O-MoS2/G) through a facile hydrothermal method, and then used to coat the commercial PP separators for Li-S batteries. The relatively low hydrothermal temperature should be a key factor for achieving the O-doped MoS2. The O dopants could expand and disturb interlayer structures of MoS2 to produce abundant active edge sites for adsorption and catalytic conversion of polysulfides. Moreover, the basal planes of MoS2 should be also activated by the O doping and exhibit enhanced chemical adsorption strength towards polysulfides for propelling electrochemical conversion. Owing to the synergistic effects of the 3D porous graphene frameworks and the inlaid O-MoS2 nanosheets, the Li-S cells with high S areal loading cathodes and O-MoS2/G@PP separators exhibit excellent electrochemical performances with a high specific capacity of 1141 mAh g−1 at the 1st cycle at 0.1 C, reversible capacities of 772 mAh g−1 at the 50th cycle at 0.2 C and 583 mAh g−1 at the 100th cycle at 0.5 C. These encouraging results provide that the heteroatom doping should be a promising approach to improve the adsorption and catalytic activity of MoS2 for propelling the polysulfide conversion in Li-S batteries.

Synthesis and Characterizations of Bioactive Glass Nanoparticle-Incorporated Triblock Copolymeric Injectable Hydrogel for Bone Tissue Engineering.

Recently, injectable hydrogels have attracted much interest in tissue engineering (TE) applications because of their controlled flowability, adaptability, and easy handling properties. This work emphasizes the synthesis and characterizations of bioactive glass (BAG) nanoparticle-reinforced poly(ethylene glycol) (PEG)- and poly(N-vinylcarbazole) (pNVC)-based minimally invasive composite injectable hydrogel suitable for bone regeneration. First, the copolymer was synthesized from a combination of PEG and pNVC through reversible addition-fragmentation chain-transfer (RAFT) polymerization and nanocomposite hydrogel constructs were subsequently prepared by conjugating BAG particles at varying loading concentrations. Gel permeation chromatography (GPC) analysis confirmed the controlled nature of the polymer. Various physicochemical characterization results confirmed the successful synthesis of copolymer and nanocomposite hydrogels that showed good gelling and injectability properties. Our optimal nanocomposite hydrogel formulation showed excellent swelling properties in comparison to the copolymeric hydrogel due to the presence of hydrophilic BAG particles. The bone cell proliferation rate was found to be evidently higher in the nanocomposite hydrogel than in the copolymeric hydrogel. Moreover, the enhanced level of ALP activity and apatite mineralization for the nanocomposite in comparison to that for the copolymeric hydrogel indicates accelerated in vitro osteogenesis. Overall, our study findings indicate BAG particle-conjugated nanocomposite hydrogels can be used as promising grafting materials in orthopedic reconstructive surgeries complementary to conventional bone graft substitutes in cancellous bone defects due to their 3D porous framework, minimal invasiveness, and ability to form any desired shape to match irregular bone defects.

Constructing Mechanical Shuttles in a Three-dimensional (3D)Porous Architecture for Selective Transportof Lithium Ions.

Lithium(Li)extraction from brinesis a major barrier to the sustainable development of batteries and alloys;however, current separation technology suffers from a trade-off between ion selectivity andpermeability. Herein, a crown ether mechanically interlocked 3D porous organic framework (Crown-POF) was prepared as the porous filler of thin-film nanocomposite membranes. Crown-POF with penta-coordinated(four O crown atoms and one N tert-amine atom)adsorptionsites enables a special recognition for Li+ion. Moreover, thefour N tert-amine atoms on each POF branch facilitate the flipping motion of Li+ion along the skeletal thread, while retaining the specified binding pattern. Accordingly, the crown ether interlocked POF network displays an ultrafast ion transfer rate, over 10 times that of the conventional porous materials.Notably, the nanocomposite membrane gives high speed and selectivity for Li+ion transport as compared with other porous solid-based mixed-matrix membranes.

Constructing Mechanical Shuttles in a Three‐dimensional (3D) Porous Architecture for Selective Transport of Lithium Ions

AbstractLithium (Li) extraction from brines is a major barrier to the sustainable development of batteries and alloys; however, current separation technology suffers from a trade‐off between ion selectivity and permeability. Herein, a crown ether mechanically interlocked 3D porous organic framework (Crown‐POF) was prepared as the porous filler of thin‐film nanocomposite membranes. Crown‐POF with penta‐coordinated (four Ocrown atoms and one Ntert‐amine atom) adsorption sites enables a special recognition for Li+ ion. Moreover, the four Ntert‐amine atoms on each POF branch facilitate the flipping motion of Li+ ion along the skeletal thread, while retaining the specified binding pattern. Accordingly, the crown ether interlocked POF network displays an ultrafast ion transfer rate, over 10 times that of the conventional porous materials. Notably, the nanocomposite membrane gives high speed and selectivity for Li+ ion transport as compared with other porous solid‐based mixed‐matrix membranes.