3D Porous Framework Research Articles

Fenton reaction-driven pro-oxidant synergy of ascorbic acid and iron oxide nanoparticles in MIL-88B(Fe)

Firstly Fe3O4-MIL-88B(Fe) was studied, and the pro-oxidant role of ascorbic acid in enhancing its catalytic properties is investigated.

Enabling a scalable composite solid electrolyte via cathode-supported scale-up processing

The designed composite solid electrolytes (CSEs) address the aggregation problems of inorganic particles and the issue of difficult reproduction of 3D porous oxide electrolyte frameworks, providing a new pathway for the scale-up of CSE synthesis.

Metal-driven folding and assembly of a minimal β-sheet into a 3D-porous honeycomb framework.

In contrast to short helical peptides, constrained peptides, and foldamers, the design and fabrication of crystalline 3D frameworks from the β-sheet peptides are rare because of their high self-aggregation propensity to form 1D architectures. Herein, we demonstrate the formation of a 3D porous honeycomb framework through the silver coordination of a minimal β-sheet forming a peptide having terminal metal coordinated 4- and 3-pyridyl ligands.

Electrostatic interactions dominate thermal conductivity and anisotropy in three-dimensional hydrogen-bonded organic frameworks

Hydrogen-bonded organic frameworks (HOFs), an emerging class of porous molecular materials assembled through hydrogen bonds (H-bonds), have shown intriguing latent for multifunctional materials or devices. Understanding thermal transport in HOFs is crucial to guiding the functional material design with desired thermal properties. Here, we report thermal transport properties in HOFs and reveal the significance of electrostatic interactions (H-bonds and π-π interactions) to heat conduction with molecular dynamics simulations. It is found that despite relatively weak H-bonds, tetracarboxylic-based frameworks (TCFs), a three-dimensional (3D) HOF, show relatively high thermal conductivity compared with known 3D porous covalent organic frameworks and metal-organic frameworks. Electrostatic interactions in TCFs dominate thermal conductivity and anisotropy but central atoms in the monomers show negligible impact. The structural analysis and x-ray diffraction patterns highlight the importance of electrostatic interactions in maintaining the high crystallinity of TCFs. The vibrational density of states and spectral thermal conductivity further demonstrate that phonon modes with frequencies below 25 THz contribute about 90 % of total thermal conductivity in TCFs, and electrostatic interactions sustain phonon modes with frequencies of 5–25 THz to carry heat. These findings provide a fundamental understanding of structure-thermal conductivity relation in HOFs and advance their applications for multifunctional materials and devices.

Efficient alcohol electro-oxidation based on a 3D Ni(II)-MOF with centrosymmetric Ni6 cluster

Designing economical and efficient anode catalysts is critical for the commercial use of direct alcohol fuel cells (DAFCs). In this work, a novel Ni(II)-based metal–organic framework (MOF), {[Ni3(μ3-OH)(TMBTI)(1,4-bib)(H3O)}n (H6TMBTI = 2,4,6-trimethylbenzene-1,3,5-triylisophthalate, 1,4-bib = 1,4-bis(1-imidazoly)benzene) (CTGU-38, CTGU = China Three Gorges University), was successfully synthesized through solvothermal method. Structural analyses reveal that the CTGU-38 possesses a unique Ni6(μ3-OH)2(COO)12 cluster and 3D porous framework with a rare (6,16)-connected topology. Further electrochemical experiments demonstrate that the CTGU-38 exhibits good electrocatalytic oxidation performance towards various alcohol fuel molecules, including the methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR), n-propanol oxidation reaction (NPOR), and isopropanol oxidation reaction (IPOR), with peak current densities ranging from 26.9 to 54.46 mA cm−2 in alkaline solution. These results indicate that the CTGU-38 appears to be a potential non-noble metal-based electrocatalyst for DAFCs, and this work provides new insights into the design of more efficient electrocatalysts at the atomic scale for energy conversion.

Hierarchical porous alumina ceramics as multi-functional support with excellent performance

Hierarchical porous nanostructure alumina ceramics (HP-Al2O3) were prepared through a novel approach involving polymer-assisted freeze-drying and subsequent calcination. The resulting material exhibits interconnected micro-meso-macro pores, distinguishing it from traditional Al2O3 nanoparticles (Al2O3-Nps) prepared without freeze-drying. By manipulating freeze-drying precursors and calcination temperatures, we tailor the morphology and structure of HP-Al2O3. Notably, the HP-Al2O3 demonstrates a remarkable 5.3-fold increase in adsorption efficiency for Congo red compared to Al2O3-Nps, attributed to its significantly larger specific surface area. The HP-Al2O3 is a versatile platform for building multi-functional composites, proved by immobilizing silver nanoparticles (AgNps) and graphitized carbonitride (g-C3N4) through chemical reduction and gas-solid reaction methods, respectively. When employed for the reduction of 4-nitrophenol and the degradation of Rhodamine B, Ag/HP-Al2O3 and g-C3N4/HP-Al2O3 display approximately 2.5 and 2.4 times higher reaction rate constants compared to Ag/Al2O3-Nps and g-C3N4/Al2O3-Nps. This enhanced catalytic performance is attributed to several key factors: the 3D porous framework of the HP-Al2O3 facilitates efficient catalyst immobilization, the microporous and mesoporous nature increases the active site and specific surface area, and the hierarchical porous structure enhances mass diffusion and light capture. Moreover, the self-supporting nature of the HP-Al2O3 simplifies separation and recovery from reaction solutions. With the integration of its hierarchical porous structure and commendable recovery properties, HP-Al2O3 emerges as a promising candidate for various functional applications, particularly in catalysis.

Metal Mo and nonmetal N, S co-doped 3D flowers-like porous carbon framework for efficient electromagnetic wave absorption

The carbon-based material co-doped with metal and nonmetal can induce electron spin redistribution and polarization configuration transformation, and consequently affected the electromagnetic wave absorption (EWA) performance. To explore this effect, we masterly prepared Mo and N, S co-doped 3D flower-like porous carbon framework (Mo/N/S-PCF) by pyrolysising the modified ZIF(Zn)-L. The EWA properties of N-PC, Mo/N-PCF and Mo/N/S-PCF show a trend of gradual enhancement. In addition, the calcination temperature plays a decisive role in regulating the amount of doping, the degree of graphitization and EWA properties of Mo/N/S-PCF. When the pyrolysis temperature is 900 °C, the optimum reflection loss of Mo/N/S-PCF can reach −53dB only with the thickness of 1.7 mm. Excellent performance of Mo/N/S-PCF is attributed to the increased dipole polarization that caused by the Mo, N and S co-doped in the carbon skeleton.

Ferric ion-assisted assembly of MXene/TiO2-graphene aerogel for ionic liquid-based supercapacitors

To achieve pseudocapacitance by driving reversible redox reactions is scientifically appealing to realize high energy density of supercapacitors (SCs). In this work, a unique ferric ions-assisted self-assembly MXene/TiO2-graphene aerogel composite (MXene/TiO2-Fe-G) is developed. The MXene/TiO2-Fe-G composite has a 3D hierarchical porous framework, large accessible specific surface area, and amorphous TiO2 modified on the surface of MXene nanosheets. Importantly, amorphous TiO2, generated from the partial oxidation of MXene, can contribute enormous pseudocapacitance via the reversible redox reaction with Lithium ions. In addition, ferric cations with variable valence states can also provide pseudocapacitance. A trinary ionic liquid-based electrolyte (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide-acetonitrile-lithium bis(trifluoromethanesulfonyl)imide, EmimTFSI-ACN-LiTFSI) with a wide electrochemical stability potential window is also formulated to match the new material. Consequently, the MXene/TiO2-Fe-G composite as the negative electrode shows a superb specific capacitance of 196.4 F g−1 at 1 A g−1. An asymmetric supercapacitor assembled with the MXene/TiO2-Fe-G anode and self-synthesized nitrogen-doped reduced graphene oxide aerogel (N-RGA) cathode can deliver a high energy density of 54 Wh kg−1 at a high-power density of 1737 W kg−1. This work provides a possibility of implementing pseudocapacitance by changing the morphology and structure of MXene composites to match the ionic liquid-based electrolyte, which can considerably enhance the performance of MXene-based SCs.

S and O doped porous carbon hollow bubble for Zn ion capacitors with enhanced energy density and long life

Zinc ion capacitors (ZICs) as a promising energy storage systems suffer low energy density and poor cyclic stability, leading to increasing attention to the development of porous carbons. Herein, S and O co-doped porous carbon hollow bubble (S-O-PC-HB) was prepared. The obtained S-O-PC-HB displays 3D porous framework structure to shorten the Zn2+ transport path. S and O dopants introduce more defects and then promote Zn2+ storage capability. The S-O-PC-HB as cathode for ZICs exhibits the largest energy density of 95.68 Wh kg−1 at 178 W kg−1. The assembled ZICs delivers a long cycling stability (92.4 % capacity retention after 20,000 cycles), which presents an alternative practice for high-performance ZICs.

Three-Dimensional Zinc-Seeded Carbon Nanofiber Architectures as Lightweight and Flexible Hosts for a Highly Reversible Zinc Metal Anode.

Uneven zinc (Zn) deposition typically leads to uncontrollable dendrite growth, which renders an unsatisfactory cycling stability and Coulombic efficiency (CE) of aqueous zinc ion batteries (ZIBs), restricting their practical application. In this work, a lightweight and flexible three-dimensional (3D) carbon nanofiber architecture with uniform Zn seeds (CNF-Zn) is prepared from bacterial cellulose (BC), a kind of biomass with low cost, environmental friendliness, and abundance, as a host for highly reversible Zn plating/stripping and construction of high-performance aqueous ZIBs. The as-prepared 3D CNF-Zn with a porous interconnected network significantly decreases the local current density, and the functional Zn seeds provide uniform nuclei to guide the uniform Zn deposition. Benefiting from the synergistic effect of Zn seeds and the 3D porous framework in the flexible CNF-Zn host, the electrochemical performance of the as-constructed ZIBs is significantly improved. This flexible 3D CNF-Zn host delivers a high and stable CE of 99.5% over 450 cycles, ensuring outstanding rate performance and a long cycle life of over 500 cycles at 4 A g-1 in the CNF-Zn@Zn//NaV3O8·1.5H2O full battery. More importantly, owing to the flexibility of the 3D CNF-Zn host, the as-assembled pouch cell shows outstanding mechanical flexibility and excellent energy storage performance. This strategy of producing readily accessible carbon from biomass can be employed to develop advanced functional nanomaterials for next-generation flexible energy storage devices.

Optimized osteogenesis of porcine bone-derived xenograft through surface coating of magnesium-doped nanohydroxyapatite

As one of the key factors influencing the outcome of guided bone regeneration, the currently used xenografts possess insufficient capability in osteogenesis. With the aim of improving the osteogenic performance of xenografts, porcine bone-derived hydroxyapatite (PHA) was prepared and subsequently coated by magnesium-doped nano hydroxyapatite (nMgHA, 10%, 20%, and 30% of Mg/Ca + Mg) through a straightforward and cost-efficient approach. The physiochemical and biological properties of nMgHA/PHAs were examined in vitro and in vivo. The inherent three-dimensional (3D) porous framework with the average pore size of 300 μm was well preserved in nMgHA/PHAs. Meanwhile, excess magnesium released from the so-called ‘surface pool’ of PHA was verified. In contrast, slower release of magnesium at lower concentrations was detected for nMgHA/PHAs. Significantly more newly-formed bone and microvessels were observed in 20%nMgHA/PHA than the other specimens. With the limitations of the present study, it could be concluded that PHA coated by 20%nMgHA may have the optimized osteogenic performance due to the elimination of the excess magnesium from the ‘surface pool’, the preservation of the inherent 3D porous framework with the favorable pore size, and the release of magnesium at an appropriate concentration that possessed osteoimmunomodulatory effects on macrophages.

Three-dimensional porous carbon framework coated with polyaniline for highly stable and selective ammonia sensing

Ammonia (NH3) sensing for environmental pollution monitoring is simultaneously required high selectivity against interfering gases, long-term stability with humidity tolerance and low detection limit, which needs further exploring. Here, the compositions of three-dimensional (3D) porous carbon framework (C-FW) coated with polyaniline (PANI@3D C-FW CPs) have been developed for highly selective and stable NH3 detection, which have been firstly prepared 3D C-FW via freezing/drying, and have been then in-situ coated with PANI. As-synthesized PANI@3D C-FW CPs present 3D porous architectures with rough surface. Beneficially, the PANI@3D C-FW CPs show a distinguished selectivity to NH3 against other interfering gases and possess 100 ppb-concentration detection limit at room temperature (∼25 °C), respectively. Remarkably, the PANI@3D C-FW CPs sensor prototypes show outstanding cycling stability to 10 ppm NH3, and 249-day long stability. Theoretically, such outstanding NH3 sensing performance might be attributed to the unique deprotonation/protonation process of PANI molecules layer and the abundant adsorption sites of 3D porous framework structure. Practically, simulation to detect NH3 using as-prepared PANI@3D C-FW CPs has been conducted with reliable sensing response.

Tröger's base derived 3D-porous aromatic frameworks with efficient exciton dissociation and well-defined reactive site for near-unity selectivity of CO2 photo-conversion

The overall photocatalytic conversion of CO2 and H2O to fuel and O2 is challenging. In this study, a series of three-dimensional Tröger's base-derived porous aromatic frameworks (3D-X-TB-PAFs (X = TEPE, TEPM, SPF)) featuring designated reaction sites and unique charge transfer properties were developed. The incorporation of V-shaped Tröger's base (TB) units and aromatic alkynes imparts the polymers with permanent porosity, additional photon scattering cross-sections, and enhanced CO2 adsorption/activation capabilities. Density functional theory calculations and optoelectronic measurements revealed the formation of intramolecular built-in polarization and electron-trap sites induced by TB, which modulated charge separation and customized reaction sites in collaboration with 3D networks. In addition, product allocation during the photoreduction of CO2 was regulated by the photooxidation of H2O. Among the as-prepared 3D-PAFs, the most efficient electron transport channel was demonstrated by the TEPE-TB-PAF with fully conjugated TEPE-T. In the absence of cocatalysts and sacrificial agents, TEPE-TB-PAF exhibits a competitive CO formation rate (194.50 μmol g−1 h−1) with near-unity selectivity (99.74%). Significantly, the low energy barrier for CO desorption and the high energy barrier for *CHO formation contribute to the high efficiency of TEPE-TB-PAF, as demonstrated by computational exploration and in situ diffuse reflectance infrared Fourier transform spectra. This work offers efficient building blocks for the synthesis of multifunctional organic photocatalysts and groundbreaking insights into the simultaneous enhancement of photocatalytic reactivity and selectivity.

Porous 3D and 2D frameworks differentiation induced by metal doping: Structure flexibility, capture behaviors, post-synthetic metal exchange and amorphous electrocatalyst transformation

The obtaining of high porosity and understanding the dynamic pore responses to various inclusion guests represents one main focus in the functionalization of metal-organic frameworks (MOFs). A new solvothermally generated MOF of {(Me2NH2)[Ni3(μ3OH)(tzba)3(H2O)3]}·8DMF (Ni3−MOF, H2tzba = 4-(1H-tetrazol-5-yl)benzoic acid) processes negative charged, new triangular [Ni3(μ3OH)(COO)3(tz)3(H2O)3] node based, MIL-88-topology resembled framework, with high void fraction of 73.3%. While the introduction of equivalent Mn2+ will greatly change the coordination assembly, leading to 2D (3,6)-grid layer of [Ni1.4Mn1.6(tzba)3(H2O)6]·12DMF (NiMn-MOF) as the first example of synergistical construction of rare [M2(tz)3(H2O)3] and [M(COO)3] nodes. The 2D layers parallelly stacked in ABAB fashion through interlayer hydrogen bonding, and generated a neutral framework with high void fraction of 72.9% and 1D mesoporous hexagonal channels with diameter of 24.0 Å. The Ni3−MOF is highly flexible and tends to close its pores after full guest removing, yet its gas accessible porosity is sensitive to residual guest in the pores and the porosity are fully reserved in organic solution phase to capture Methylene Blue and iodine. The inherent strong structure dynamic of Ni3−MOF facilitates post-synthetic metal exchange of the Ni2+ by Mn2+, Co2+, Cu2+ and Cd2+, as well as the in-situ formation of amorphous Ni(OH)2 electrocatalyst for dual water splitting with full recovery of costly organic ligands. For the NiMn-MOF, large gas accessible porosity with Langmuir surface area of 1052 m2 g−1, as well as guest dependent shrink-swell behavior was obtained. The NiMn-MOF is found to be an effective porous adsorbent to capture the iodine in either solution or gaseous phase, with uptake up to 2.4 mol iodine per mol of MOFs and capture of iodine with concentration lower to 5.0 × 10−5 mol/L.

Integration of bimetallic spinel sulfides CoNi2S4 nanosheets with the hierarchically porous wood framework as efficient bifunctional catalysts for urea-assisted hydrogen generation

Replacing anodic oxygen evolution reaction (OER) by urea oxidation reaction (UOR) provides a feasible approach to achieve high-efficiency hydrogen (H2) generation. However, the design of a robust catalyst for urea-assisted H2 generation remains a difficult problem. In this study, an innovative strategy to integrate bimetallic spinel sulfides CoNi2S4 nanosheet arrays with graphitized carbonized wood (denoted as CoNi2S4/GCW) for synergistically optimizing the electroconductivity and the hierarchical porous structure of the CoNi2S4/GCW catalyst is proposed. Benefitting from the optimized three-dimensional (3D) porous structure and the CoNi2S4 nanosheet arrays, the CoNi2S4/GCW catalyst exhibit brightly electrocatalytic performance toward both for UOR and hydrogen evolution reaction (HER). The synthesized CoNi2S4/GCW needs an ultralow potential (1.29 V vs. RHE) for UOR and a comparative small overpotential (119 mV) for HER at a current density of 20 mA cm−2, respectively, enabling a two-electrode configuration at a cell voltage of 1.42 V to output 20 mA cm−2 for urea-assisted electrocatalytic H2 generation. The enhanced urea-assisted performance of CoNi2S4/GCW is supposed to arise from a synergistic effect between the CoNi2S4 nanosheets and the 3D hierarchical porous wood framework, which offers sufficient active sites and expedite the mass transfer process between them. This work exhibits the application of bimetallic spinel sulfides CoNi2S4 in urea-assisted H2 generation and provides a promising strategy for utilizing sustainable wood for developing versatile electrocatalyst.

High-Efficiency Electroreduction of Nitrite to Ammonia on Ni Nanoparticles Strutted 3D Honeycomb-Like Porous Carbon Framework.

Electroreduction of nitrite (NO2 - ) to ammonia (NH3 ) provides a sustainable approach to yield NH3 , whilst eliminating NO2 - contaminants. In this study, Ni nanoparticles strutted 3D honeycomb-like porous carbon framework (Ni@HPCF) is fabricated as a high-efficiency electrocatalyst for selective reduction of NO2 - to NH3 . In 0.1 M NaOH with NO2 - , such Ni@HPCF electrode obtains a significant NH3 yield of 12.04 mg h-1 mgcat. -1 and a Faradaic efficiency of 95.1 %. Furthermore, it exhibits good long-term electrolysis stability.

A self-supported 3D porous high entropy alloy with progressive formation of needle-shaped nanowires during reactions for maintained excellent electrocatalytic oxygen evolution

An efficient 3D porous bulk electrocatalyst is a feasible way to improve the conductivity. Herein, the preparation of a novel self-supporting 3D porous bulk FeCoNiMgB catalyst exhibits excellent electrocatalytic activity and stability properties towards OER. The self-supporting 3D porous framework structure catalyst possesses multiple advantages including large surface area, excellent conductivity, leading to the fast mass and charge transfers, low electrochemical impedance and fast water splitting reaction kinetics. As a result, the 3D porous bulk FeCoNiMgB catalyst requires substantially lower overpotential (234 mV) with a small Tafel slope (36.1 mV dec−1) as compared to pure FeCoNiMgB powders and RuO2 electrodes, as well as stable catalytic properties for over 72 h with no obvious evidence of degradation. Comparative structural characterization and DFT calculations reveal that the needle-shaped nanowires with Fe rich are formed from many open pores during the OER process, which helps to reduce the rate determining step energy barrier (O∗→OOH∗) for OER, and thus has excellent long-term electrochemical stability for continuous oxygen production under alkaline conditions. This work provides a new feasible and promising protocol to realize a novel self-supporting 3D porous bulk high entropy alloy catalyst as an inexpensive catalyst for efficient water splitting.

Structures and electrical conductivities of a series of coordination polymers based on tetrathiafulvalene

Three novel tetrathiafulvalene-based coordination polymers, [Co(H2TTFTB) (H2O)4DMF] (1), [Co6(HTTFTB)4(H2O)] (2) and [Mn4(TTFTB)4(H2O)7(DMF)] (3) (H4TTFTB = tetrathiafulvalene tetrabenzoate), were synthesized by simple solvothermal method. These complexes exhibit different topologies: complex 1 shows three-dimensional (3D) hydrogen-bonded framework (HOF) constructed by one-dimension (1D) [Co(H2TTFTB)] chains; complex 2 exhibits a porous 3D framework with three kinds of channels, which consisted of {Co3II(COO)8} SBUs connected with TTFTB4‒ ligands along [0 0 1] direction; the porous framework of complex 3 is composed of two types of helical nanotubes. Electrical conductivity (σ) measurements revealed moderate σ values for these three complexes, among which complex 3 shows the highest value of 3.17 × 10–6 S cm‒1 which is comparable to other promising conductive materials consisting of H4TTFTB ligands.

Oriented Porous NASICON 3D Framework via Freeze-Casting for Sodium-Metal Batteries.

Sodium-metal batteries are promising candidates for low-cost, large-format energy storage systems. However, sodium-metal batteries suffer from high interfacial resistance between the electrodes and the solid electrolyte, leading to poor electrochemical performance. We demonstrate a sodium superionic conductor (NASICON) with an oriented porous framework of sodium aluminum titanium phosphate (NATP) fabricated by the freeze-casting technique, which shows excellent properties as a solid electrolyte. Using X-ray computed tomography, we confirm the uniform low-tortuosity channels present along the thickness of the scaffold. We infiltrated the porous NATP scaffolds with sodium vanadium phosphate (NVP) cathode nanoparticles achieving mass loadings of ∼3-4 mg cm-2, which enables short sodium ion diffusion path lengths. For the resulting hybrid cell, we achieved a capacity of ∼90 mAh g-1 at a specific current of 50 mA g-1 (∼300 Wh kg-1) for over 100 cycles with ∼94% capacity retention. Our study offers valuable insights for the design of hybrid solid electrolyte-cathode active material structures to achieve improved electrochemical performance through low-tortuosity ion transport networks.

Ice template induced assembly strategy for preparation of 3D porous carbon frameworks from low-cost carbon quantum dots for high-performance lithium-ion batteries

Consider the natural similarities between the structures of coal tar pitch and carbon quantum dots (CQDs), the mass-production of low-cost zero-dimensional (0D) CQDs was achieved by using the mild oxidation with hydrogen peroxide (H2O2). The as-obtained CQDs possesses a uniformly distributed size with a diameter of 4.16 ± 0.46 nm, many oxygen-containing functional groups, distinct crystallinity nature and a production yield of ∼18 wt%. Subsequently, ice-template induced assembly coupled with carbonization strategy reveals a transition from 0D CQDs to 3D porous carbon frameworks. Differing from the well-defined porous carbon, the obtained porous carbon frameworks consist of cross-linked and twisted nanosheets, achieving a well-developed hierarchical porous structure with a reasonable specific surface area and a gradient distribution of meso/micropores. LIBs based on porous carbon frameworks as anode materials show excellent long-cycle performance, as evidenced by reversible capacity of up to 273 mAh·g−1 after 1000 charge-discharge cycles at 2000 mA·g−1. The research emphasizes a green method of preparing CQDs from representative low-value coal tar pitch and the directional transition from 0D CQDs to 3D porous carbon frameworks, providing a promising idea to prepare functional carbon materials and endow them opportunities for LIBs anode.