Zeolitic Imidazolate Framework-Derived Pt-Co in Nanofibrous Networks as Stable Oxygen Reduction Electrocatalysts with Low Pt Loading.

Proton-exchange membrane fuel cell technology is a key component in the future zero-carbon energy system, generating power from carbon-free fuels, such as green hydrogen. However, the high Pt loading in conventional fuel cell electrodes to maintain electrocatalytic activity and durability, especially on the cathode for oxygen reduction, is the Achilles heel for the worldwide deployment of fuel cell technologies. To minimize Pt consumption for oxygen reduction, we synthesized Pt-Co-based electrocatalysts with meticulous structuring from micrometer to the atomic scale based on reaction pathways. The resulting Pt-Co-based electrocatalysts contain only 1.9 wt% Pt, which is 20 times lower than the conventional Pt-C catalysts for fuel cells. By utilizing electrospinning and in situ synthesis, we anchored three-dimensionally structured zeolitic imidazolate frameworks on continuously connected nanofibrous electrospun mats. The Pt-Co@Pt-free nanowire (PC@PFN) electrocatalysts contain Pt-Co nanoparticles (NPs) and non-Pt elements, Co-containing sites comprising NPs, nanoclusters, and N-coordinated Co single atoms. Despite the ultralow Pt loading in PC@PFN, the mass activity exceeds the U.S. Department of Energy 2025 target by 2.8 times and retains 85.5% of the initial activity after 80,000 durability test cycles, possibly owing to synergistic reaction pathways between Pt and non-Pt sites.

Aided diagnosis of cervical spondylotic myelopathy using deep learning methods based on electroencephalography.

Cervical spondylotic myelopathy (CSM) is the most severe type of cervical spondylosis. It is challenging to achieve early diagnosis with current clinical diagnostic tools. In this paper, we propose an end-to-end deep learning approach for early diagnosis of CSM. Electroencephalography (EEG) experiments were conducted with patients having spinal cord cervical spondylosis and age-matched normal subjects. A Convolutional Neural Network with Long Short-Term Memory Networks (CNN-LSTM) model was employed for the classification of patients versus normal individuals. In contrast, a Convolutional Neural Network with Bidirectional Long Short-Term Memory Networks and attention mechanism (CNN-BiLSTM-attention) model was used to classify regular, mild, and severe patients. The models were trained using focal Loss instead of traditional cross-entropy Loss, and cross-validation was performed. Our method achieved a classification accuracy of 92.5 % for the two-class classification among 40 subjects and 72.2 % for the three-class classification among 36 subjects. Furthermore, we observed that the proposed model outperformed traditional EEG decoding models. This paper presents an effective computer-aided diagnosis method that eliminates the need for manual extraction of EEG features and holds potential for future auxiliary diagnosis of spinal cord-type cervical spondylosis.

An MgAl layered double hydroxide as a new transition metal-free anode for lithium-ion batteries.

A carbonate intercalated magnesium aluminum layered double hydroxide is used as an anode material for lithium-ion batteries, displaying a maximum discharge specific capacity of 814 mA h g-1 at 200 mA g-1 in this work through utilizing the valence variation of Mg and the conversion between LiOH and LiH/Li2O.

Aqueous Chloride-Ion Battery within a Neutral Electrolyte Based on a CoFe-Cl Layered Double Hydroxide Anode.

Aqueous chloride-ion batteries (ACIBs) with environmental friendliness and high safety hold great potential to fulfill the green energy demand for ocean desalination. Herein, for the first time, a composite consisting of Cl--intercalated CoFe layered double hydroxides (CoFe-Cl-LDH) cross-linked with CNTs (CoFe-Cl-LDH/CNT) is synthesized and demonstrated to be a novel high-performance anode for ACIBs in a neutral NaCl aqueous solution. While exhibiting a high initial capacity of ∼190 mAh g-1 at 200 mA g-1, CoFe-Cl-LDH/CNT is capable of delivering a reversible capacity of ∼125 mAh g-1 after 200 cycles. At a high current density of 400 mA g-1, it still holds a capacity of ∼120 mAh g-1. The excellent Cl- storage performance can be contributed to the unique topochemical transformation feature that reverses intercalation/deintercalation of Cl- along with valence changes of Co2+/Co3+ and Fe2+/Fe3+ during charge/discharge and the improved electronic conductivity by hybridizing with CNTs. It is interesting that the invertible insertion/extraction of interlayer H2O was discovered, which could be beneficial to the capacity after cycles to a certain extent. The Cl--intercalated LDH material declared in this work shows its feasibility on Cl- capture/release in aqueous anion-type batteries and provides a new opportunity for future development of ACIBs or aqueous desalination technology.

Universal Synthesis of Half-Metallic Diatomic Catalysts for Efficient Oxygen Reduction Electrocatalysis.

Developing efficient and low-cost noble-free metal electrocatalysts is an urgent requirement. Herein, a one-step, solid-state template-assisted method for fabricating isolated half-metallic diatomic M, Zn─N─C (M═Fe, Co, and Ni) catalysts is reported. In particular, the fabricated Fe, Zn─N─C structure exhibits superior oxygen reduction reaction capabilities with a half-wave potential of 0.867 V versus RHE. The Mossbauer spectra reveal that the Fe, Zn─N─C half-metallic diatomic catalyst has a large proportion of the D2 site (ferrous iron with a medium spin state). Density functional theory (DFT) reveals that in Fe, Zn─N─C structures, the zinc sites play a unique role in accelerating the protonation process of O2 in ORR. In assembled zinc-air batteries, a maximum power density of 138 mW cm-2 and a capacity of 748 mAh g zn-1 can be obtained. This work fabricates a series of efficient M, Zn─N─C diatomic electrocatalysts, and the developed solid-state reaction method can hopefully apply in other energy conversion and storage fields.

Solution plasma synthesis of Pt-decorated Bi12O17Cl2 photocatalysts for efficient upcycling of plastics.

Photocatalytic upcycling of plastic waste is a promising approach to relieving pressure caused by solid waste, but the rational design of novel efficient photocatalysts remains a challenge. Herein, we utilize subnano-sized platinum (Pt)-based photocatalysts for plastic upcycling. A solution plasma strategy is developed to fabricate Pt-decorated Bi12O17Cl2 (SP-BOC). The Pt in an oxidant state and oxygen vacancies optimize the electronic structure for fast charge transfer. As a result, SP-BOC displays high performance for upcycling polyvinyl chloride (PVC) and polylactic acid (PLA) into acetic acid and formic acid, with yield rate and selectivity of 6.07 mg g-1cat. h-1 and 94 %, and 47.43 mg g-1cat. h-1 and 55.1 %, respectively. In addition, the dichlorination efficiency of PVC reaches 78.1 % within 10 h reaction, effectively reducing the environmental hazards associated with PVC waste disposal treatments. This research provides insight into the effective conversion of plastics into high-value chemicals, contributing to the reduction of carbon and toxic emissions in a practical and meaningful way, and offering a useful way for solving challenges of waste management and environmental sustainability.

Two-Dimensional LDH Film Templating for Controlled Preparation and Performance Enhancement of Polyamide Nanofiltration Membranes.

Tailored design of high-performance nanofiltration membranes that can be used in a variety of applications such as water desalination, resource recovery, and sewage treatment is desirable. Herein, we describe the use of layered double hydroxides (LDH) intermediate layer to control the interfacial polymerization between trimesoyl chloride (TMC) and piperazine (PIP) for the preparation of polyamide (PA) membrane. The dense surface of LDH layer and its unique mass transfer behavior influence the diffusion of PIP, and the supporting role of the LDH layer allows the formation of ultrathin PA membranes. By only changing the concentration of PIP, a series of membranes with controllable thickness from 10 to 50 nm and tunable crosslinking-degree can be prepared. The membrane prepared with a higher concentration of PIP shows excellent performance for divalent salt retention with water permeance of 28 Lm-2 h-1 bar-1 , high rejection of 95.1 % for MgCl2 and 97.1 % for Na2 SO4 . While the membrane obtained with a lower concentration of PIP can sieve dye molecules of different sizes with a flux of up to 70 Lm-2 h-1 bar-1 . This work demonstrates a novel strategy for the controllable preparation of high-performance nanofiltration membranes and provides new insights into how the intermediate layer affects the IP reaction and the final separation performance.

High entropy alloy nanoparticles encapsulated in graphitised hollow carbon tubes for oxygen reduction electrocatalysis.

High entropy alloys (HEAs) with a tunable alloy composition and fascinating synergetic effects between various metals have attracted significant attention in the field of electrocatalysis, but their potential is limited by inefficient and unscalable fabrication methodologies. This work proposes a novel solid-state thermal reaction method to synthesise HEA nanoparticles encapsulated in an N-doped graphitised hollow carbon tube. This facile method is simple and efficient and involves no use of organic solvents during the fabrication process. The synthesized HEA nanoparticles are confined by the graphitised hollow carbon tube, which is possibly beneficial for preventing the aggregation of alloy particles during the oxygen reduction reaction (ORR). In a 0.1 M KOH solution, the HEA catalyst FeCoNiMnCu-1000(1 : 1) exhibits an onset and half-wave potential of 0.92 V and 0.78 V (vs. RHE), respectively. We assembled a Zn-Air battery with FeCoNiMnCu-1000 as a catalyst for the air electrode, and a power density of 81 mW cm-2 and a long-term durability of >200 h were achieved, which is comparable to the performance of the state-of-the-art catalyst Pt/C-RuO2. This work herein offers a scalable and green method for synthesising multinary transition metal-based HEAs and highlights the potential of HEA nanoparticles as electrocatalysts for energy storage and conversion.

Pansharpening Model of Transferable Remote Sensing Images Based on Feature Fusion and Attention Modules.

The purpose of the panchromatic sharpening of remote sensing images is to generate high-resolution multispectral images through software technology without increasing economic expenditure. The specific method is to fuse the spatial information of a high-resolution panchromatic image and the spectral information of a low-resolution multispectral image. This work proposes a novel model for generating high-quality multispectral images. This model uses the feature domain of the convolution neural network to fuse multispectral and panchromatic images so that the fused images can generate new features so that the final fused features can restore clear images. Because of the unique feature extraction ability of convolution neural networks, we use the core idea of convolution neural networks to extract global features. To extract the complementary features of the input image at a deeper level, we first designed two subnetworks with the same structure but different weights, and then used single-channel attention to optimize the fused features to improve the final fusion performance. We select the public data set widely used in this field to verify the validity of the model. The experimental results on the GaoFen-2 and SPOT6 data sets show that this method has a better effect in fusing multi-spectral and panchromatic images. Compared with the classical and the latest methods in this field, our model fusion obtained panchromatic sharpened images from both quantitative and qualitative analysis has achieved better results. In addition, to verify the transferability and generalization of our proposed model, we directly apply it to multispectral image sharpening, such as hyperspectral image sharpening. Experiments and tests have been carried out on Pavia Center and Botswana public hyperspectral data sets, and the results show that the model has also achieved good performance in hyperspectral data sets.

Colloidal Stabilization of Submicron-Sized Zeolite NaA in Ethanol-Water Mixtures for Nanostructuring into Thin Films and Nanofibers.

Despite the growing use of organic or mixed solvents in zeolite processing, most studies focus only on aqueous suspension systems. We investigated the colloidal characteristics of submicron-sized zeolite NaA in mixed ethanol-water solvents. The effects of the mixing ratio of solvents and various additives on the dispersion of the zeolite powders were studied. The zeolite NaA particles were destabilized in solvent mixtures at a high ethanol-to-water ratio, a reduction in the zeta potential was observed, and the destabilization was rationalized by the Derjaguin, Landau, Verwey, Overbeek (DLVO) theory. An improved stabilization of the zeolite NaA suspensions was achieved in ethanol-rich solvent mixtures using nonionic low molecular weight organic additives, but not with their ionic counterparts such as anionic, cationic surfactants or inorganic acids or bases. Polyethylene glycol (PEG)-400 was found to be a good dispersant for the submicron-sized zeolite NaA particles in the ethanol-water mixtures, which was attributed to its interaction with the zeolite surface, leading to an increased zeta potential. The PEG-stabilized zeolite suspensions led to low suspension viscosities as well as uniform and consistent spin-coated films.

MgAl Saponite as a Transition-Metal-Free Anode Material for Lithium-Ion Batteries.

Transition-metal compounds (oxides, sulfides, hydroxides, etc.) as lithium-ion battery (LIB) anodes usually show extraordinary capacity larger than the theoretical value due to the transformation of LiOH into Li2O/LiH. However, there has rarely been a report relaying the transformation of LiOH into Li2O/LiH as the main reaction for LIBs, due to the strong alkalinity of LiOH leading to battery deterioration. In this work, layered silicate MgAl saponite (MA-SAP) is applied as a -OH donor to generate LiOH as the anode material of LIBs for the first time. The MA-SAP maintains a layered structure during the (dis)charging process and has zero-strain characteristic on the (001) crystal plane. In the discharging process, Mg, Al, and Si in the saponite sheets become electron-rich, while the active hydroxyl groups escape from the sheets and combine with lithium ions to form LiOH in the "caves" on sheets, and the LiOH continues to decompose into Li2O and LiH. Consequently, the MA-SAP delivers a maximum capacity of 536 mA h·g-1 at 200 mA·g-1 with a good high-current discharging ability of 155 mA h·g-1 after 1000 cycles under 1 A·g-1. Considering its extremely low cost and completely nontoxic characteristics, MA-SAP has great application prospects in energy storage. In addition, this work has an enlightening effect on the development of new anodes based on extraordinary mechanisms.

Janus Hollow Nanofiber with Bifunctional Oxygen Electrocatalyst for Rechargeable Zn-Air Battery.

Zn-air battery technologies have received increasing attention, while the application is hindered by the sluggish kinetics of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). In order to explore an efficient method to fabricate a high-performance electrocatalyst via modification of advanced nanostructure, a coaxial electrospinning method with in-situ synthesis and subsequent carbonization to construct 3D flexible Janus-like electrocatalysts is developed. The resulting Janus nanofibers have a unique core-shell hollow fiber structure, where NiFe alloy electrocatalysts supported by N-doped carbon nanobelt are located on the inner wall of the carbon layer, and leaf-like Co-N nanosheets are anchored on the outer wall of the carbon layer. As a result, the electrocatalyst exhibits excellent bifunctional catalytic performance for ORR and OER, demonstrating the small potential gap value of 0.73 V between the ORR half-wave potential and the OER potential at 10 mA cm-2 , which is even comparable to the mixed commercial noble catalyst with 20% Pt/C and RuO2 . The rechargeable Zn-air battery is constructed and displays a large open-circuit voltage of 1.44 V, high power density (130 mW cm-2 ) and energy density (874 Wh kg-1 ). This study provides a concept to synthesize and construct high performance bifunctional electrocatalysts.

Application of a new integrated low-profile anterior plate and cage system in single-level cervical spondylosis: a preliminary retrospective study.

BACKGROUND: Although ACDF has been widely used in treating cervical spondylosis and related diseases, the complications along with this anterior surgical technique have hindered its application and affected the postoperative outcome of the patients. Here, we investigated the clinical and radiological outcomes of a new integrated low-profile anterior plate and cage system for anterior cervical discectomy and fusion (ACDF) in treating cervical spondylosis. METHODS: A total of 96 cervical spondylosis patients who underwent single-level ACDF between 2018 to 2020 in our institute were enrolled. There were 28 patients using the new implants and 68 patients using the zero-profile (Zero-P) implants. The Japanese Orthopedic Association (JOA) score and the visual analog scale (VAS) were used to evaluate the clinical outcomes. The cervical and segmental Cobb angle and range of motion (ROM) were used to assessed the radiological outcomes. Incidence of complications were also recorded. All data were recorded at pre-operation, 6-month and 12-month post-operation. RESULTS: All patients were followed-up for at least 1-year, the mean follow-up time was over one year. The fusion rate was similar in the two groups. There was no significant difference in the postoperative JOA score recovery rate, postoperative VAS score of neck and arm pain, postoperative ROM, and incidence of complications between two groups (P > 0.05). However, postoperative cervical and segmental Cobb angle were better maintained in the new low-profile implant group compared to Zero-P group. CONCLUSIONS: The clinical outcomes of the new low-profile implant were satisfactory and comparable to that of zero-profile system. It may have advantages in improving and maintaining the cervical lordosis, and can be an alternative device for single-level cervical spondylosis treated with ACDF.

Random Occupation of Multimetal Sites in Transition Metal-Organic Frameworks for Boosting the Oxygen Evolution Reaction.

Developing robust oxygen evolution reaction (OER) electrocatalysts with excellent performance is essential for the conversion of renewable electricity to clean fuel. Herein, we present a facile concept for the synthesis of efficient high-entropy metal-organic frameworks (HEMOFs) as electrocatalysts in a one-step solvothermal synthesis. This strategy allows control of the microstructure and corresponding lattice distortion by tuning the metal ion composition. As a result, the OER activity was improved by optimizing the coordination environment of the metal catalytic center. The optimized Co-rich HEMOFs exhibited a low overpotential of 310 mV at a current density of 10 mA cm-2 , better than a RuO2 catalyst tested under the same conditions. The finding of lattice distortion of the HEMOFs provides a new strategy for developing high-performance electrocatalysts for energy conversion.

Polishing micropollutants in municipal wastewater, using biogenic manganese oxides in a moving bed biofilm reactor (BioMn-MBBR).

Conventional wastewater treatment plants (WWTPs) cannot remove organic micropollutants efficiently, and thus various polishing processes are increasingly being studied. One such potential process is utilising biogenic manganese oxides (BioMnOx). The present study operated two moving bed biofilm reactors (MBBRs) with synthetic sewage as feed, one reactor feed was spiked with Mn(II) which allowed the continuous formation of BioMnOx by Mn-oxidising bacteria in the suspended biofilms (i.e. BioMn-MBBR). Spiking experiments with 14 micropollutants were conducted to investigate if BioMnOx combined with MBBR could be utilised to polish micropollutants in wastewater treatment. Results show enhanced removal by BioMn-MBBR over control MBBR (without BioMnOx) for specific micropollutants, such as diclofenac (36% vs. 5%) and sulfamethoxazole (80% vs. 24%). However, diclofenac removal was significantly inhibited when municipal wastewater was fed, and a further batch experiment demonstrates the reduced removal of diclofenac could be due to (unusual) higher pH in municipal wastewater compared to synthetic sewage. A shift in bacterial community was also observe in BioMn-MBBR over long-term operation. Overall, BioMn-MBBR in this study shows great potential for practical application in removing a larger range of micropollutants, which could be applied as an efficient polishing step for typical municipal wastewater.

A phase conversion method to anchor ZIF-8 onto a PAN nanofiber surface for CO2 capture.

Polyacrylonitrile (PAN) nanofibers were prepared by electrospinning and coated with zeolitic imidazolate framework-8 (ZIF-8) by a phase conversion growth method and investigated for CO2 capture. The PAN nanofibers were pre-treated with NaOH, and further coated with zinc hydroxide, which was subsequently converted into ZIF-8 by the addition of 2-methyl imidazolate. In the resulting flexible ZIF-8/PAN composite nanofibers, ZIF-8 loadings of up to 57 wt% were achieved. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) showed the formation of evenly distributed submicron-sized ZIF-8 crystals on the surface of the PAN nanofibers with sizes between 20 and 75 nm. X-ray photoelectron spectroscopy (XPS) and carbon-13 nuclear magnetic resonance (13C NMR) investigations indicated electrostatic interactions and hydrogen bonds between the ZIF-8 structure and the PAN nanofiber. The ZIF-8/composite nanofibers showed a high BET surface area of 887 m2 g-1. CO2 adsorption isotherms of the ZIF-8/PAN composites revealed gravimetric CO2 uptake capacities of 130 mg g-1 (at 298 K and 40 bar) of the ZIF-8/PAN nanofiber and stable cyclic adsorption performance.

Alkali-Etched Ni(II)-Based Metal-Organic Framework Nanosheet Arrays for Electrocatalytic Overall Water Splitting.

The exploration of efficient electrocatalysts is the central issue for boosting the overall efficiency of water splitting. Herein, pertinently creating active sites and improving conductivity for metal-organic frameworks (MOFs) is proposed to tailor electrocatalytic properties for overall water splitting. An Ni(II)-MOF nanosheet array is presented as an ideal material model and a facile alkali-etched strategy is developed to break its NiO bonds accompanied with the introduction of extra-framework K cations, which contribute to creating highly active open metal sites and largely improving the electrical conductivity. As a result, the assembled defect-Ni-MOF||defect-Ni-MOF electrolyte cell delivers a lower and stable voltage of 1.50 V at 10 mA cm-2 in alkaline medium for overall water splitting, comparable to the combination of iridium and platinum as benchmark catalysts.

Electrospinning of Metal-Organic Frameworks for Energy and Environmental Applications.

Herein, recent developments of metal-organic frameworks (MOFs) structured into nanofibers by electrospinning are summarized, including the fabrication, post-treatment via pyrolysis, properties, and use of the resulting MOF nanofiber architectures. The fabrication and post-treatment of the MOF nanofiber architectures are described systematically by two routes: i) the direct electrospinning of MOF-polymer nanofiber composites, and ii) the surface decoration of nanofiber structures with MOFs. The unique properties and performance of the different types of MOF nanofibers and their derivatives are explained in respect to their use in energy and environmental applications, including air filtration, water treatment, gas storage and separation, electrochemical energy conversion and storage, and heterogeneous catalysis. Finally, challenges with the fabrication of MOF nanofibers, limitations for their use, and trends for future developments are presented.

Rational Localization of Metal Nanoparticles in Yolk-Shell MOFs for Enhancing Catalytic Performance in Selective Hydrogenation of Cinnamaldehyde.

The development of sustainable catalysts to simultaneously improve activity and selectivity remains a challenge. Herein, it is demonstrated that metal nanoparticles (MNPs) can be encapsulated into a yolk-shell metal-organic framework (MOF) with controllable spatial localization to optimize catalytic performance. When the MNPs are located in the void space between the shell and the core of the MOF, the resulting MNPs@MOF composites show both high catalytic activity and selectivity toward the hydrogenation of α,ß-unsaturated aldehydes. In particular, the easily recoverable and stable Ptvoid @MOF(Y) shows an exceptionally high selectivity of 98.2 % for cinnamyl alcohol at a high conversion of 97 %. The excellent performance can be attributed to easy diffusion of the reactants to access highly exposed MNPs in the MOF support, as well as the improved adsorption of the reactant and desorption of the product due to the appropriate metal-support interaction and rich void space between core and shell.

Partial Sulfurization of a 2D MOF Array for Highly Efficient Oxygen Evolution Reaction.

A feasible strategy for the in situ growth of two-dimensional (2D) [Ni3(OH)2(1,4-BDC)2-(H2O)4]·2H2O (Ni-BDC; 1,4-BDC = 1,4-benzenedicarboxylate) and the subsequent partial sulfurization treatment for the decoration of nickle sulfide (NiS) is developed. The fabricated hierarchically structured Ni-BDC@NiS as a synergistic electrocatalyst shows extremely high activity toward the oxygen evolution reaction (OER). The optimal Ni-BDC@NiS catalyst acquires a current density of 20 mA cm-2 at a lower overpotential of 330 mV and low Tafel slope of 62 mV dec-1, outperforming most previously reported Ni-based sulfide catalysts. Clearly, the combination of the NiS and Ni-BDC array contributed to the improvement of electron transfer, promotion of water adsorption, and increase of rich active species. In addition, the in situ created hierarchical structure not only affords feasible access for mass transport but also strengthens structural integrity, contributing to efficient and stable OER performance. This general and effective strategy anchoring conductive active species on a porous metal-organic framework (MOF) thus provides an efficient way to fabricate synergistic electrocatalysts for the OER.