Hierarchical Micropores Research Articles

Rare [Cu4I2]2+ cationic cluster-based metal-organic framework and hierarchical porous composites design for effective detection and removal of roxarsone and antibiotics

Fluorescence quenching induced by photoinduced electron transfer (PET) stands as an effective strategy for identifying water pollutants. Herein, a novel (4, 8)-connected three-dimensional framework Cu(I)-MOF ([Cu2I(tpt)]n) with unique 8-connected [Cu4I2]2+ cationic clusters is designed by employing the nitrogen-rich ligand (Htpt = 5-[4(1H-1,2,4-triazol-1-yl)]phenyl-2H-tetrazole). Water-stabilized Cu(I)-MOF exhibits outstanding fluorescence properties, facilitating its application in detecting organic pollutants in water. Benefiting from the fact that the Cu(I)-MOF possesses a higher lowest unoccupied molecular orbitals (LUMO) energy level than that of the analyte, the rapid d-PET can occur, entitling Cu(I)-MOF to a sensitive fluorescence quenching response to roxarsone (ROX), nitrofurazone (NFZ) and nitrofurantoin (NFT) (with detection limits as low as 0.13 µM, 0.15 µM, and 0.13 µM, respectively). The nitrogen-containing sites of melamine foam (MF) are utilized to facilitate the anchoring and growth of Cu-MOF crystals, which enables the preparation of hierarchical microporous − macroporous Cu(I)-MOF/MF composites. The ordered porous structure of Cu(I)-MOF/MF provides cavities and open sites for the efficient removal of ROX (qmax = 210.6 mg∙g−1), NFZ (qmax = 111.5 mg∙g−1) and NFT (qmax = 238.9 mg∙g−1) from water. This characteristic endows the Cu(I)-MOF/MF with rapid and recyclable adsorption capacity. Therefore, this work provides valuable insights to address the problem of detection and removal of pollutants in the aquatic environment.

Hierarchical microporous Ni-based electrodes enable “Two Birds with One Stone” in highly efficient and robust anion exchange membrane water electrolysis (AEMWE)

Anion exchange membrane water electrolysis (AEMWE) is currently the most promising technology to produce green hydrogen. However, the lack of cost-effective and scalable methods for fabricating robust and highly active non-noble metal electrodes primarily inhibits its large-scale industrialization. This study unveils an effective strategy for tackling this challenge by creating a novel hierarchical conical-microporous nickel-based electrode, through a synergistic implementation of both rapid and scalable atmospheric plasma spraying (APS) and laser texturing (LT) processes. The resultant NA-LT-CA electrodes exhibits remarkable catalytic performances for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Notably, the AEMWE cell with NA-LT-CA electrodes yields a remarkable enhancement of cell efficiency, toward a reduction in cell voltage of 244 mV at 0.8 A cm−2, compared to the NA-CA electrode (without LT) cell. The notable achievements stem from the improved bubble dynamic contributed by the introduced hierarchical micropores into NA-LT-CA electrodes by the LT process. Moreover, the cell equipped with the NA-LT-CA electrodes demonstrates an outstanding durability, maintaining its performance for 1000 h without visible degradation under 0.8 A cm−2, which can be ascribed to the distinctive “pinning effect” produced by the transition layer during the LT process, adeptly preventing the catalytic layer peeling off even under industrial-scale current densities. Notably, introducing the LT process delivers a dual benefit, akin to achieving “Two Birds with One Stone.”. This work supports the effectiveness of combining APS and LT processes as a potent strategy for fabricating high-efficiency and enduring electrodes, thus advancing AEMWE for practical industrial applications.

Engineering a robust, multifunctional superhydrophobic/oleophobic microporous aluminum surface via a two-step chemical etching process

Surfaces with unique wettability properties are gaining attention for their widespread applications. Particularly, superhydrophobic surfaces, known for their remarkable water-repellent properties and low adhesion, have gained substantial interest in recent years owing to their versatile applications. Despite their versatile applications, the durability of such surfaces faces challenges like mechanical abrasion, chemical deterioration, and environmental factors, limiting their effectiveness in real-world scenarios. In this study, we successfully fabricated a mechanically robust, cost-effective, and easy-to-process superhydrophobic surface on an aluminum substrate using a two-step chemical etching process. Initially, the hierarchical microporous (HMP) structure was created through chemical etching, followed by the deposition of a self-assembled layer of PFOTS onto the fabricated aluminum substrate, attaining superhydrophobic and oleophobic properties. The surface exhibits remarkable superhydrophobicity with a water contact angle of 162°, while coupled with oleophobic characteristics against a wide spectrum of oils with surface tensions ranging from 21.5–63.3 mN m − 1. We conducted comprehensive characterizations of surface morphology and chemical composition, while also investigating the impact of surface morphology on wettability, physicochemical stability, and antibacterial properties. Mechanical testing revealed that the surface maintained its superhydrophobicity even after undergoing linear abrasion for a distance of 120 cm under an applied pressure of 12.25 kPa. Furthermore, the surface displayed self-cleaning, and anti-fouling, along with significant antibacterial properties against Staphylococcus aureus bacteria, creating a 23 mm zone of inhibition. We believe the proposed method will inspire the fabrication of large-scale superhydrophobic metallic surfaces endowed with multifunctional properties, making them highly suitable for a wide range of industrial applications.

Facile synthesis of ultrahigh-surface-area and hierarchically porous carbon for efficient capture and separation of CO2 and enhanced CH4 and H2 storage applications

Ultrahigh surface area and hierarchically microporous carbons functionalized with heteroatoms are critical for many applications, particularly gas storage and separation. However, the facile synthesis of such carbons remains challenging. Herein, we present a single-step activation strategy for producing porous polymer-based ultrahigh surface area carbons through melamine-mediated potassium oxalate activation. As prepared carbon possesses a uniform distribution of heteroatoms and hierarchical micropores, and exhibits a maximum specific surface area of 3463 m2/g, which is among the best reported for carbon materials. The presence of heteroatoms (N and O), along with its ultra-high surface area and hierarchical microporous structure, plays a significant role in storing large amounts of CO2 (22.8 mmol/g at 298 K/25 bar), CH4 (10.1 mmol/g at 298 K/25 bar) and H2 (5.2 wt% at 77 K/50 bar). Furthermore, it demonstrates a selective capture of CO2 over N2, CH4 and H2. The developed carbon is highly suitable for gas storage and the separation of CO2 from flue gas and syngas.

Highly Ordered Hierarchical Porous Single‐Atom Fe Catalyst with Promoted Mass Transfer for Efficient Electroreduction of CO2

AbstractElectrocatalysts are crucial to drive the electrochemical carbon dioxide reduction reaction (CO2RR) which lower the energy barrier, tune the intricate reaction pathways and suppress competitive side‐reaction. Beyond the efficient active sites and advantageous local environment, a rapid mass transfer ability is also crucial for the catalyst design. However, it is rare that research has been done to investigate in detail the mass transfer process in CO2RR, and expose the underlying relationship between mass transfer and final performance. Here, a single‐atom Fe‐N‐C catalyst is shown with a highly ordered porous substrate containing hierarchical micropores, mesopores, and macropores. Such a delicate porous structure significantly facilitates the mass transfer process toward the isolated Fe sites, achieving excellent CO2RR performance, especially in the limited mass transfer region in a H‐cell with a maximum CO partial current density of ‐19 mA cm−2. Operando electrochemical impedance spectroscopy and relevant distributed relaxation times analysis reveal the rapidly decreased mass transfer resistance with the increase of reduction potential. The Lattice Boltzmann method with Discrete Element method (LBM‐DEM) simulations are further performed to exhibit the origin of enhanced CO2RR performance from the facilitated gas diffusion process.

Melamine-participant hydrogen-bonded organic frameworks with strong hydrogen bonds and hierarchical micropores driving extraction of nitroaromatic compounds

Enrichment and detection of trace pollutants in the real matrix are essential for evaluating water quality. In this study, benefiting from the good affinities of 1,3,6,8-tetra(4-carboxylphenyl)pyrene) (H4TBAPy) with itself and melamine (MA) respectively, the composite hydrogen-bonded organic frameworks (HOFs, MA/PFC-1), PFC-1 self-assembled by 1,3,6,8-tetra(4-carboxylphenyl)pyrene), were successfully constructed by the mild strategy of solvent evaporation at room temperature. Through a series of characterizations, such as Fourier transform infrared spectra, X-ray diffraction, thermal gravimetric analyses, and N2 adsorption-desorption, etc., the MA/PFC-1 was confirmed to be a stable and excellent material. In addition, it possessed high surface area, hierarchical micropores, strong hydrogen bonds, and rich function groups containing N and O heteroatoms, since the newly introduced MA could be another hydrogen bonding motif, as well as increased the polarity of reaction solvent. These advantages make MA/PFC-1 be an ideal coating material for solid phase microextraction (SPME). Satisfactory enrichment factors for nitroaromatic compounds (NACs) were got by the MA/PFC-1 fiber under the optimized conditions obtained by the control variables (extraction time of 60 min, extraction temperature of 80 °C, desorption time of 6 min, desorption temperature of 260 °C, pH value of 7, and stirring speed of 250 rpm). MA/PFC-1 was further used to develop an analytical method for NACs based on head-space SPME coupled with gas chromatography‒mass spectrometry (GC‒MS). The developed method with low limits of detection (4.30–20.83 ng L−1) and good reproducibility (relative standard deviations <8.6%). The excellent performance allowed the successful application of the developed method in the determinations of trace NACs in real water samples with recoveries of 80.1%–119%. This study proposed a mild approach to synthesize composite HOFs via doping MA and developed an environmentally friendly method for the precise determinations of NACs in the environment.

Porphyrin-based conjugated microporous adsorbent material for the efficient remediation of hexavalent chromium from the aquatic environment.

The encapsulation and eradication of anions from water have received a lot of scrutinize and are extremely important for virtuous production and environmental treatment. To prepare extremely efficient adsorbents, a highly functionalized and conjugated microporous porphyrin-based adsorbent material (Co-4MPP) was synthesized using the Alder Longo method. Co-4MPP featured a hierarchical microporous and mesoporous layered structure containing nitrogen and oxygen-based functional groups with a specific surface area of 685.209 m2/g and a pore volume of 0.495 cm3/g. Co-4MPP demonstrated a greater Cr (VI) adsorption empathy than the pristine porphyrin-based material did. The effects of various parameters such as pH, dose, time, and temperature were explored on the Cr (VI) adsorption by Co-4MPP. The pseudo-second-order model and the Cr (VI) adsorption kinetics were in agreement (R2 = 0.999). The Langmuir isotherm model matched the Cr (VI) adsorption isotherm, demonstrating the optimum Cr (VI) adsorption capacities: 291.09, 307.42, and 339.17 mg/g at 298K, 312K, and 320K, correspondingly, with remediation effectiveness of 96.88%. The model evaluation further revealed that Cr (VI) adsorption mechanism on Co-4MPP was endothermic, spontaneous, and entropy-rising. The detailed discussion of the adsorption mechanism suggested that it could be a reduction, chelation, and electrostatic interaction, in which the protonated nitrogen and oxygen-containing functional groups on the porphyrin ring interacted with Cr (VI) anions to form a stable complex, thus remediating Cr (VI) anions efficiently. Moreover, Co-4MPP demonstrated strong reusability, maintaining 70% of its Cr (VI) elimination rate after four consecutive adsorptions.

Specific separation of flavonoids isomers by defect modulated metal-organic framework HKUST-1: Experiment and density functional theory analysis

Discovering and separating active monomers from natural products is an efficient way to develop new drugs, but faces the difficulty in complex and time-consuming separation process. Metal-organic frameworks (MOFs) are considered a promising separation strategy due to their molecular recognition properties, but their microporous nature poses challenges for capturing most natural compounds with molecule sizes larger than 20 Å. For the first time, this study proposed a simple and efficient approach to separate active monomeric components with larger diameters from structurally similar natural compounds by defect modulation strategy. In this study, defective HKUST-1 with hierarchical microporous/ mesoporous structures and Cu1+/Cu2+ mixed-valence sites was rapidly synthesized. The defective MOF demonstrated specific loading of silibinin A&B from silymarin containing seven structurally similar flavonoids within 5 min, and high separation capacity with the purity of ∼91.2% after primary separation. FTIR, XPS, and DFT calculation revealed the site competition mechanism for specific recognition and loading, where silibinin A&B preferentially acted on Cu2+ and Cu1+ clusters with the highest binding energy via hydrogen and coordination bonds, respectively. Compared to traditional separation techniques, the separation approach via defective MOF shows multiple advantages including high specificity, high separation efficiency, and easy to operate.

High-Performance Proton Exchange Membrane Fuel Cells Enabled by Highly Hydrophobic Hierarchical Microporous Carbon Layers Grafted with Silane

The employing of a microporous layer (MPL) with an appropriate pore size distribution and hydrophobicity between the carbon paper substrate and catalyst layer of proton exchange membrane fuel cells (PEMFCs) plays a decisive role in the management of gas transport and the crucial prevention of water flooding. However, enhancing the performance of PEMFCs by directly altering the structure of MPL has rarely been reported. The present work addresses this issue by fabricating hierarchical porous carbon (HPC) enabled MPLs via a dual template method employing zinc oxide and sodium chloride, and a silane-coupling agent is chemically grafted to HPC components of the MPL to improve water drainage instead of applying a conventional hydrophobic treatment. The physical and electrochemical properties of gas diffusion layers formed with different MPLs are analyzed, and the results indicate that the proposed MPL with excellent water drainage and efficient gas transport capability facilitates a higher output power density (863.62 mW cm–2) and lower mass transport impedance superior to a conventional MPL. This work provides a generic and feasible structure design for the development of MPLs that significantly improves the performance of PEMFCs.

A nanocaged cadmium-organic framework with high catalytic activity on the chemical fixation of CO2 and deacetalization-knoevenagel condensation

Heterogeneous MOFs catalysts have attracted great attention due to the efficient combination of heterogeneity (easy post-reaction separation and recyclability) and homogeneity (active sites and porosity), which inspire us to explore functional MOFs materials with higher catalytic activity on the chemical fixation of CO2 and deacetalization-Knoevenagel condensation. Herein, the self-assembly of Cd2+ and H6TDP under acidic solvothermal condition generated one cadmium-organic framework of {[(CH3)2NH2]2 [Cd2 (TDP) (H2O)2]⋅3DMF⋅2H2O}n (NUC-29, H6TDP = 2,4,6-tris(2,4-dicarboxyphenyl)pyridine) with nano-caged voids and hierarchical microporous channels, which were built on the combination of two kinds of mononuclear units of [Cd (1) (COO)3(H2O)] and [Cd (2) (COO)3(H2O)]. After the removal of solvent molecules by activation, NUC-29 possesses the coexistence of Lewis acid-base sites on the inner surface of channels including all exposed Cd2+ sites and Npyridine sites, which render it an excellent recyclable heterogeneous catalyst to facilitate the cycloaddition reaction of epoxides with CO2 and deacetalization-Knoevenagel condensation under mild conditions.

Ligand‐Conformer‐Induced Formation of Zirconium–Organic Framework for Methane Storage and MTO Product Separation

In pursuit of novel adsorbents with efficient adsorptive gas storage and separation capabilities remains highly desired and challenging. Although the documented zirconium-tricarboxylate-based metal-organic frameworks (MOFs) have displayed a variety of topologies encompassing underlying and geometry mismatch ones, the employed organic linkers are exclusively rigid and poorly presenting one type of conformation in the resultant structures. Herein, a used and semirigid tricarboxylate ligand of H3 TATAB was judiciously selected to isolate a zirconium-based spe-MOF after the preliminary discovery of srl-MOF. Single-crystal X-ray diffraction reveals that the fully deprotonated TATAB linker in spe-MOF exhibits two distinct conformers, concomitant with popular Oh and rare S6 symmetrical Zr6 molecular building blocks, generating an unprecedented (3,3,12,12)-c nondefault topology. Specifically, the spe-MOF exhibits structurally higher complexity, hierarchical micropores, open metal sites free and rich electronegative groups on the pore surfaces, leading to relatively high methane storage capacity without considering the missing-linker defects and efficient MTO product separation performance.

Ligand‐Conformer‐Induced Formation of Zirconium–Organic Framework for Methane Storage and MTO Product Separation

AbstractIn pursuit of novel adsorbents with efficient adsorptive gas storage and separation capabilities remains highly desired and challenging. Although the documented zirconium‐tricarboxylate‐based metal–organic frameworks (MOFs) have displayed a variety of topologies encompassing underlying and geometry mismatch ones, the employed organic linkers are exclusively rigid and poorly presenting one type of conformation in the resultant structures. Herein, a used and semirigid tricarboxylate ligand of H3TATAB was judiciously selected to isolate a zirconium‐based spe‐MOF after the preliminary discovery of srl‐MOF. Single‐crystal X‐ray diffraction reveals that the fully deprotonated TATAB linker in spe‐MOF exhibits two distinct conformers, concomitant with popular Oh and rare S6 symmetrical Zr6 molecular building blocks, generating an unprecedented (3,3,12,12)‐c nondefault topology. Specifically, the spe‐MOF exhibits structurally higher complexity, hierarchical micropores, open metal sites free and rich electronegative groups on the pore surfaces, leading to relatively high methane storage capacity without considering the missing‐linker defects and efficient MTO product separation performance.

The POM@MOF hybrid derived hierarchical hollow Mo/Co bimetal oxides nanocages for efficiently activating peroxymonosulfate to degrade levofloxacin

Herein, we reported the design and fabrication of polyoxometalates coupling metal-organic framework (POM@MOF) hybrids derived hierarchical hollow Mo/Co bimetal oxides nanocages (Mo/Co HHBONs) for the peroxymonosulfate (PMS) activation to degrade levofloxacin (Lev). The Mo/Co HHBONs are hollow nanocages with high specific-surface areas and hierarchical micropores, mesopores, and macropores. In addition to compositional modulation, polyoxometalate (H3PMo12O40·nH2O) exhibited striking effect on the textural properties of Mo/Co HHBONs. The Mo/Co HHBONs had outstanding catalytic activity with first order-kinetics that were 6 − 10 times higher those previously reported. They exhibited good adaptability over a pH range of 3 − 11, as well as excellent universality and reusability. By altering the surface porosity, electronic structure, and oxygen vacancies of Co3O4, hetero-metal Mo doping induced Mo/Co HHBONs significantly promote the generation of reactive oxygen species, including •OH, SO4•−, O2•−, and 1O2. Density functional theory indicated that Mo/Co HHBONs had better adsorption, enhanced electron-transfer abilities, and a longer O-O bond length than did Co3O4, for improved catalytic reactivity. This research provides a new strategy to design the POM@MOF hybrids derived hierarchical hollow nanocages with highly PMS activating capacity for the removal of antibiotics and other refractory contaminants.

Structural Diversity of Zirconium Metal-Organic Frameworks and Effect on Adsorption of Toxic Chemicals.

While linkers with various conformations pose challenges in the design and prediction of metal-organic framework (MOF) structures, they ultimately provide great opportunities for the discovery of novel structures thereby enriching structural diversity. Tetratopic carboxylate linkers, for example, have been widely used in the formation of Zr-based MOFs due to the ability to target diverse topologies, providing a promising platform to explore their mechanisms of formation. However, it remains a challenge to control the resulting structures when considering the complex assembly of linkers with unpredicted conformations and diverse Zr6 node connectivities. Herein, we systematically explore how solvents and modulators employed during synthesis influence the resulting topologies of Zr-MOFs, choosing H4TCPB-Br2 (1,4-dibromo-2,3,5,6-tetrakis(4-carboxyphenyl)benzene) as a representative tetratopic carboxylate linker. By modulating the reaction conditions, the conformations of the linker and the connectivities of the Zr6 node can be simultaneously tuned, resulting in four types of structures: a new topology (NU-500), she (NU-600), scu (NU-906), and csq (NU-1008). Importantly, we have synthesized the first 5-connected Zr6 node to date with the (4,4,4,5)-connected framework, NU-500. We subsequently performed detailed structural analyses to uncover the relationship between the structures and topologies of these MOFs and demonstrated the crucial role that the flexible linker played to access varied structures by different degrees of linker deformation. Due to a variety of pore structures ranging from micropores to hierarchical micropores and mesopores, the resulting MOFs show drastically different behaviors for the adsorption of n-hexane and dynamic adsorption of 2-chloroethyl ethyl sulfide (CEES) under dry and humid conditions.

Hierarchical dual-porous hydroxyapatite doped dendritic mesoporous silica nanoparticles based scaffolds promote osteogenesis in vitro and in vivo

Biomaterial based scaffolds for treating large bone defects require excellent biocompatibility and osteoconductivity. Here we report on the fabrication of hydroxyapatite-dendritic mesoporous silica nanoparticles (HA-DMSN) based scaffolds with hierarchical micro-pores (5 µm) and nano-pores (6.4 nm), and their application for bone regeneration. The in vitro studies demonstrated good biocompatibility of dissolution extracts, as well as enhanced osteogenic potential indicated by dose-dependent upregulation of bone marker gene expression (osteocalcin gene (OCN), osteopontin gene (OPN), collagen type I alpha 1 gene (CoL1A1), runt-related transcription factor 2 gene (RUNX2), and integrin-binding sialoprotein gene (IBSP)), alkaline phosphatise (ALP) activity, and alizarin red staining. The in vivo studies showed that HA-DMSN scaffolds significantly increased bone formation in a rat cranial bone defect model after 4 weeks healing. Our study provides a simple method to fabricate promising inorganic scaffolds with hierarchical pores for bone tissue engineering.

Superior nitrogen-doped activated carbon materials for water cleaning and energy storing prepared from renewable leather wastes

The fabrication of nitrogen-doped activated carbons (N-ACs) from leather solid wastes (LSW), a huge underutilized bioresource, by different activation methods was investigated. N-AC prepared by KOH activation (named KNAC) exhibited superior physical and chemical properties with much higher BET surface area (2247 m2 g−1) and more abundant hierarchical micropores than those activated by nano-CaCO3 (CNAC) or by direct carbonization (NNAC). KOH activation decreased the total nitrogen content in KNAC, but it increased the ratio of surface nitrogen species. KOH activation also significantly promoted the conversion of nitrogen species in the carbon material to pyridinic N. Potential applications of the prepared N-ACs were evaluated, and they were tested as adsorbents to remove phenols from water and as the anodes of lithium batteries. The high surface area, abundant micropores, and plentiful surface pyridinic N guaranteed KNAC a superior nitrogen-doped activated carbon that could serve as an excellent adsorbent to remove phenols (282 mg/g) from waste water as well as an outstanding electrode material with a high and stable charge/discharge capacity (533.54 mAh g−1 after 150th cycle). The strategy of LSW conversion to versatile N-ACs turns waste into treasure and could promote the sustainable development of our society.

Polymer Interfacial Self-Assembly Guided Two-Dimensional Engineering of Hierarchically Porous Carbon Nanosheets.

Two-dimensional (2D) carbon nanosheets with micro- and/or mesopores have attracted great attention due to unique physical and chemical properties, but well-defined nanoporous carbon nanosheets with tunable thickness and pore size have been rarely realized. Here, we develop a polymer-polymer interfacial self-assembly strategy to achieve hierarchically porous carbon nanosheets (HNCNSs) by integrating the migration behaviors of immiscible ternary polymers with block copolymer (BCP)-directed self-assembly. The balanced interfacial compatibility of BCP allows the migration of a BCP-rich phase to the interface between two immiscible homopolymer major phases (i.e., homopoly(methyl methacrylate) and homopolystyrene), where the BCP-rich phase spreads thinly to a thickness of a few nanometers to decrease the interfacial tension. BCP-directed coassembly with organic-inorganic precursors constructs an ordered mesostructure. Carbonization and chemical etching yield ultrathin HNCNSs with hierarchical micropores and mesopores. This approach enables facile control over the thickness (5.6-75 nm) and mesopore size (25-46 nm). As an anode material in a potassium ion battery, HNCNSs show high specific capacity (178 mA h g-1 at a current density of 1 A g-1) with excellent long-term stability (2000 cycles), by exploiting the advantages of the hierarchical pores and 2D nanosheet morphology (efficient ion/electron diffusion) and of the large interlayer spacing (stable ion insertion).

CeOx-Decorated Hierarchical NiCo2S4 Hollow Nanotubes Arrays for Enhanced Oxygen Evolution Reaction Electrocatalysis.

Developing hollow self-supported nanotube arrays with hierarchical microporous and abundant multiactive sites shows great promise for oxygen evolution reaction (OER) electrocatalysis. Herein, a facile and low-cost strategy of NiCo2S4 hollow nanotubes arrays decorated with CeOx nanoparticles (NPs) assembled on a flexible support carbon cloth (CC) for enhanced OER performance is reported. The obtained hierarchical nanoarrays CeOx/NiCo2S4/CC exhibited excellent activity toward OER with an overpotential (270 mV) at 10 mA cm-2, relatively weak Tafel slope, and distinguished durability. CeOx/NiCo2S4/CC nanoarrays not only provide fast electronic transmission and well-defined connection to the substrate but also defective sites and electron transfer by the introduction of CeOx NPs. This new strategy was offered to construct low-cost and effectively hierarchical structural electrocatalysts containing rare-earth species.

Probing nanocolumnar silver nanoparticle/zinc oxide hierarchical assemblies with advanced surface plasmon resonance and their enhanced photocatalytic performance for formaldehyde removal

Recent advances in photocatalysis focus on the development of materials with hierarchical structure and on the surface plasmon resonance (SPR) phenomenon exhibited by metal nanoparticles (NPs). In this work, both are combined in a material where size‐controllable Ag‐NPs are uniformly loaded onto the hierarchical microporous and mesoporous and nanocolumnar structures of ZnO, resulting in Ag‐NP/ZnO nanocomposites. The embedded Ag‐NPs slightly decrease the hydrophobicity of fibrous ZnO, improve its wettability, and increase the absorption of formaldehyde (H2CO) onto the photocatalyst, all of this resulting in excellent photodegradation of formaldehyde in aqueous solution. Besides, we found that Ag‐NPs with optimal size not only accelerate the charge transfer to the surface of ZnO, but also strengthen the SPR effect in the intercolumnar channels of fibrous ZnO particles combining with high concentration of photo‐generated radical species. The micro‐to‐mesoporous ZnO is like a nanoarray packed Ag‐NPs. With Ag‐NPs of diameter 2.5 &lt; ϕ &lt; 6.5 nm, ZnO exhibits the most superior photodegradation rate constant value of 0.0239 min−1 with total formaldehyde removal of 97%. This work presents a new feasible approach involving highly sophisticated Ag‐NP/ZnO architecture combining the SPR effect and hierarchically ordered structures, which results in high photocatalytic activity for formaldehyde photodegradation.

Hierarchical Biocarbons with Controlled Micropores and Mesopores Derived from Kapok Fruit Peels for High-Performance Supercapacitor Electrodes

Hierarchical microporous and mesoporous biocarbons derived from kapok fruit peels were prepared by a two-step method. First, a carbon precursor was prepared from the kapok fruit peels by precarboni...