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Molybdenum carbide (MoC) has emerged as a promising material for capacitive deionization (CDI), but the poor electrochemical kinetics in conventional MoC owing to the bulk structure and low electric conductivity limit its CDI performance. To address this challenge, herein, we develop a novel strategy to synthesize ultrafine MoC nanocrystals that are embedded within a three-dimensional nitrogen-doped carbon framework (NC/MoC). This synthesis method involves the space-confined pyrolysis of molybdate precursors within metal-organic frameworks (MOFs). In this process, molybdates are confined into the MOF crystalline structure, where MOFs provide a confined reactor and carbon source. The resulting NC/MoC with the uniformly distributed MoC nanocrystals provides sufficient active sites for the electrosorption of salt ions, while the MOF-derived NC matrix facilitates charge transfer and provides the space-confined effect for preventing the possible aggregations of MoC nanocrystals during the CDI process. The NC/MoC exhibits an impressive salt adsorption capacity (SAC, 84.2 mg g-1, 1.2 V), rapid desalination rate, and high cycling stability (91.4% SAC retention after 200 cycles), better than those of most previously reported carbon-based CDI materials. Besides, the possible mechanisms are systematically investigated by ex situ characterization and density functional theory calculations. This study opens up new avenues for the construction of metal carbide-based nanocrystals for CDI and other electrochemical applications.
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Iron-based mixed polyanion phosphate Na4Fe3(PO4)2P2O7 (NFPP) is recognized as a promising cathode for Sodium-ion Batteries (SIBs) due to its low cost and environmental friendliness. However, its inherent low conductivity and sluggish Na+ diffusion limit fast charge and low-temperature sodium storage. This study pioneers a scalable synthesis of hollow core-shelled Na4Fe2.4Ni0.6(PO4)2P2O7 with tiny-void space (THoCS-0.6Ni) via a one-step spray-drying combined with calcination process due to the different viscosity, coordination ability, molar ratios, and shrinkage rates between citric acid and polyvinylpyrrolidone. This unique structure with interconnected carbon networks ensures rapid electron transport and fast Na+ diffusion, as well as efficient space utilization for relieving volume expansion. Incorporating regulation of lattice structure by doping Ni heteroatom to effectively improve intrinsic electron conductivity and optimize Na+ diffusion path and energy barrier, which achieves fast charge and low-temperature sodium storage. As a result, THoCS-0.6Ni exhibits superior rate capability (86.4â mAh g-1 at 25â C). Notably, THoCS-0.6Ni demonstrates exceptional cycling stability at -20 °C with a capacity of 43.6â mAh g-1 after 2500â cycles at 5â C. This work provides a universal strategy to design the hollow core-shelled structure with tiny-void space cathode materials for reversible batteries with fast-charge and low-temperature Na-storage features.
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The electrocatalytic 5-hydroxymethylfurfural (HMF) oxidation reaction coupling with hydrogen evolution reaction (HER) serves as a promising strategy to generate both high-value-added products and clean energy, which is limited by the poor catalytic efficiency of bifunctional electrocatalysts and unclear electrocatalytic mechanism for HMF oxidation reaction. Herein, we fabricate a bifunctional NiSe2-NiMoO4 heterostructure nanowire electrocatalyst for the conversion of HMF to 2,5-furandicarboxylic acid (FDCA) and simultaneous H2 production. As expected, the NiSe2-NiMoO4 exhibits outstanding activity and selectivity toward HMF oxidation reaction. In particular, at a potential of 1.50 V, the yield of FDCA could reach 98 % with a faradaic efficiency of 96.5 %, as well as excellent stability. Density functional theory calculation results demonstrate that the NiSe2-NiMoO4 heterostructure could tune the adsorption energy of HMF, facilitate high-valence active species formation, and enhance electronic conductivity. Furthermore, a two-electrode electrolyzer assembled using NiSe2-NiMoO4 as a bifunctional catalyst requires 1.53 V to acquire a current density of 50 mA cm-2, which is 201 mV lower than that of water electrolysis. This work provides new insights for designing multifunctional catalysts for biomass upgrading coupled with hydrogen evolution.
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One of the difficulties limiting covalent organic frameworks (COFs) from becoming excellent adsorbents is their stacking/aggregation architectures owing to poor morphology/structure control during the synthesis process. Herein, an inorganic-organic nanoarchitectonics strategy to synthesize the MXene/COF heterostructure (Ti3 C2 Tx /TAPT-TFP) is developed by the assembly of ß-ketoenamine-linked COF on the Ti3 C2 Tx MXene nanosheets. The as-prepared Ti3 C2 Tx /TAPT-TFP retains the 2D architecture and high adsorption capacity of MXenes as well as large specific surface area and hierarchical porous structure of COFs. As a proof of concept, the potential of Ti3 C2 Tx /TAPT-TFP for solid-phase microextraction (SPME) of trace organochlorine pesticides (OCPs) is investigated. The Ti3 C2 Tx /TAPT-TFP based SPME method achieves low limits of detection (0.036-0.126 ng g-1 ), wide linearity ranges (0.12-20.0 ng g-1 ), and acceptable repeatabilities for preconcentrating trace OCPs from fruit and vegetable samples. This study offers insights into the potential of constructing COF or MXene-based heterostructures for the microextraction of environmental pollutants.
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The two-phase reaction of Na3 V2 (PO4 )3 - Na1 V2 (PO4 )3 in Na3 V2 (PO4 )3 (NVP) is hindered by low electronic and ionic conductivity. To address this problem, a surface-N-doped NVP encapsulating by N-doped carbon nanocage (N-NVP/N-CN) is rationally constructed, wherein the nitrogen is doped in both the surface crystal structure of NVP and carbon layer. The surface crystal modification decreases the energy barrier of Na+ diffusion from bulk to electrolyte, enhances intrinsic electronic conductivity, and releases lattice stress. Meanwhile, the porous architecture provides more active sites for redox reactions and shortens the diffusion path of ion. Furthermore, the new interphase of Na2 V2 (PO4 )3 is detected by in situ XRD and clarified by density functional theory (DFT) calculation with a lower energy barrier during the fast reversible electrochemical three-phase reaction of Na3 V2 (PO4 )3 - Na2 V2 (PO4 )3 - Na1 V2 (PO4 )3 . Therefore, as cathode of sodium-ion battery, the N-NVP/N-CN exhibited specific capacities of 119.7 and 75.3 mAh g-1 at 1 C and even 200 C. Amazingly, high capacities of 89.0, 86.2, and 84.6 mAh g-1 are achieved after overlong 10000 cycles at 20, 40, and 50 C, respectively. This approach provides a new idea for surface crystal modification to cast intermediate Na2 V2 (PO4 )3 phase for achieving excellent cycling stability and rate capability.
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Hydrodeoxygenation (HDO) is an indispensable approach to produce renewable biofuels and value-added chemicals using natural biomass and its derivatives. 2,5-Dimethylfuran (DMF) is considered to be a very promising liquid biofuel, and it can be fabricated by HDO of the biomass derivative 5-hydroxymethylfurfural (HMF). Herein, a highly efficient bifunctional catalyst, Co/HAP(Ce), was fabricated by anchoring highly dispersed Co on Ce-doped hydroxyapatite (HAP(Ce)). Co/HAP(Ce) displayed excellent HDO catalytic activity to convert HMF to DMF, and 99% HMF conversion and 96% DMF selectivity can be obtained under 150 °C, 2 MPa H2 conditions for 5 h. Density functional theory calculations revealed that H2 can be more easily activated by Co/HAP(Ce). Systematic studies confirmed that the high activity of Co/HAP(Ce) can be ascribed to the desired acid-alkali properties, highly dispersed cobalt species and strong metal-support interactions. This research provides a cost effective approach for designing efficient catalysts for HDO of biomass and its derivatives.
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Shape-selective stannosilicates have been post-synthesized for the hydration of epoxide to diols. A simple acid treatment has been employed to remove extensively the interlayer double four ring units, converting the three-dimensional (3D) UTL germanosilicate into a 2D layered IPC-1P intermediate. Isomorphous incorporation of tetrahedrally coordinated Sn active centers was realized via solid-liquid treatment of IPC-1P with diammonium hexachlorostannate aqueous solution, which was accompanied by the spontaneous condensation of neighboring silica-rich cfi layers upon calcination and structural construction of a 3D PCR structure. Sn-PCR stannosilicates with tunable Sn contents were thus prepared. With Sn-derived robust Lewis acidity confined in the intersecting 10- and 8-ring channels, the Sn-PCR (Si/Sn molar ratio of 77) catalyst served as a shape-selective nanoreactor for the hydration of ethylene oxide (EO) into ethylene glycol (EG), exhibiting a remarkable EO conversion (99.5 %) as well as a steady EG selectivity (>98.4 %) at greatly reduced H2 O/EO molar ratio and near-ambient reaction temperature.
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Visible-light-driven amines oxidation coupled with hydrogen peroxide (H2 O2 ) generation is a promising way to convert solar energy to chemical energy. Herein, a series of hyper-cross-linked polymers (HCPs) photocatalysts with different arenes monomers, including benzene (BE), diphenyl (DP), p-terphenyl (TP), or p-quaterphenyl (QP), were synthesized by simple Friedel-Crafts alkylation reaction. Owing to the maximum monomer's conjunction degree and excellent oxygen (O2 ) adsorption capacity, QP-HCPs exhibited highest photocatalytic activity for benzylamine oxidation coupled with H2 O2 generation under the irradiation of 455â nm Blue LED lamp. More than 99 % of benzylamine could be converted to N-benzylidenebenzylamine within 60â min. In addition, nearly stoichiometric H2 O2 was synchronously obtained with a high production rate of 9.3â mmol gcat -1 h-1 . Our work not only demonstrated that the photocatalytic activity of HCPs photocatalysts significantly depends on monomer's conjunction degree, but also provided a new strategy for converting solar energy to chemical energy.
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Capacitive deionization (CDI) provides a promising option for affordable freshwater while simultaneously storing energy, but its large-scale application is usually limited owing to the poor performance of conventional materials in natural (oxygenated) saline water. Herein, we report heterointerface optimization in a covalent organic framework (COF)-on-MXene heterostructure achieving a high CDI performance for desalination of oxygenated saline water. The 2D heterostructure with the optimal core-shell architecture inherits the high conductivity and reversible ion intercalation/deintercalation ability of MXene, and the hierarchical porous structure, large porosity, and extraordinary redox capacity of COFs. Thanks to the heterointerface optimization, the MXene@COF heterostructure exhibits a very stable cycling performance over 100 CDI cycles with a maximum NaCl adsorption capacity of 53.1 mg g-1 in oxygenated saline water, among the state-of-the-art values for CDI electrodes and also exceeding those of most MXene-based or 2D materials. This study highlights the importance of heterointerface optimization in MXene-organic 2D heterostructures to promote CDI of natural (oxygenated) saline water.
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Estructuras Metalorgánicas , Purificación del Agua , Adsorción , Electrodos , Aguas SalinasRESUMEN
Herein, a series of hyper-cross-linked polymers (HCPs) photocatalysts were synthesized through Friedel-Crafts alkylation reaction, in which benzene served as monomer and dichloromethane (DCM), dichloroethane (DCE) as well as 1,4-dimethoxybenzene (DMB) served as crosslinker. It was found that different crosslinker can change the energy level of conduction and valence band of HCPs, which is crucial for the generation of reactive oxygen species (ROS), and the separation efficiency as well as mobility of photo-generated carriers. Among of these prepared HCPs photocatalysts, DCM-HCPs exhibited highest conversion and selectivity toward benzylamine oxidation under the irradiation of blue LED lamp (455 nm) and sunlight in air atmosphere. The highest apparent quantum yield (AQY) of DCM-HCPs is 0.44%. More importantly, a high yield of H2O2 (TOF = 5712.67 µmol gcat-1 h-1) was synchronously obtained during the process of benzylamine oxidation. Synchronous-illumination X-ray photoelectron spectroscopy (SI-XPS) was used to investigate the charge transfer mechanism of HCPs. The results revealed that the photoelectrons transferred from crosslinker (-CH2-) to benzene ring for inducing benzylamine oxidation to N-benzylidenebenzylamine and H2O2 production. In addition, a series of amines and sulfides can also be smoothly oxidized at the similar conditions.
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Aminas , Polímeros , Benceno , Bencilaminas , Catálisis , Peróxido de HidrógenoRESUMEN
Fabrication of biofuels and chemicals from renewable biomass is highly desirable to replace petrochemicals. Hydrogenolysis of biomass derived 5-hydroxymethylfurfural (HMF) is a promising way to obtain furanic fuels. In this paper, we describe the preparation of a CoSi-PS catalyst derived from cobalt phyllosilicate using a silica sol as the silica source. CoSi-PS exhibited excellent catalytic performance for the hydrogenolysis reaction of HMF to produce liquid 2,5-dimethylfuran (DMF) biofuel. 100% conversion of HMF and 97.5% selectivity for DMF were achieved at 170 °C and 1.5 MPa H2 for 4 h, which was superior to most of the reported catalysts. The excellent performance can be attributed to the strong interactions between the metal and support, highly dispersed cobalt nanoparticles and the Lewis acid sites induced by the coordinated unsaturated Co(II) sites in phyllosilicate.
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Cuprous oxide (Cu2O) is a p-type semiconductor with excellent catalytic activity and stability that has gained much attention because it is non-toxic, abundant, and inexpensive. Porous carbon materials have large specific surface areas, which offer abundant electroactive sites, enhance the electrical conductivity of materials, and prevent the aggregation of Cu2O nanocubes. In this study, a composite with high electrocatalytic activity was prepared based on Cu2O nanocubes anchored onto three-dimensional macroporous carbon (MPC) by a simple, eco-friendly, and cheap method for hydrazine detection. Due to the synergistic effect of MPC and Cu2O, the sensor exhibited high electrocatalytic activity, sensitivity, better selectivity, and low limit of detection. The resulting sensor could be a sensitive and effective platform for detecting hydrazine and promising practical applications.
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Carbono , Cobre , HidrazinasRESUMEN
Development of high-performance, economic, and stable non-noble metal catalysts is a still formidable challenge in hydrogen evolution reaction (HER) that must be overcome to alleviate the energy and environmental crisis. Herein, we designed and fabricated N-doped carbon nanoframes encapsulated by CoP nanoparticles (CoP-NCN). The 3D porous structure of the ZIF-67-derived N-doped carbon shortened the charge and mass transport pathways, contributing to enhanced electrocatalytic performance. Moreover, the synergistic effects of excellent conductivity, abundant mesopores, and high-activity CoP nanoparticles led to remarkable electrocatalytic activity toward HER with an extremely low overpotential of 120 mV at 10 mA cm-2 and long-term stability. We further indicate that the fantastic HER catalytic ability of CoP-NCN is attributed to the good conductivity and the abundant active sites. The present study provides a promising avenue toward the design of cost-effective HER electrocatalysts.
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Hidrógeno , Nanopartículas , Carbono , Catálisis , PorosidadRESUMEN
The leaf-shaped copper oxide (CuO) was first fabricated by a direct precipitation method. Then, the flake-shaped Co-Ni layered double hydroxides (CoNi-LDHs) were grown on the leaf-shaped CuO by using an electrodeposition method to form a unique nanostructured electrocatalyst. Due to the unique structural and compositional advantages, CoNi-LDHs wrapped around the leaf-shaped CuO exhibited good electrocatalytic characteristics. The optimized CuO/CoNi-LDHs exhibited improved non-enzymatic electrochemical sensing performance for glucose, with a reliable linear range (0.1 µM-0.384 mM) and a low limit of detection (0.065 µM, S/N = 3). The utilization of the CuO/CoNi-LDHs sensor for glucose detection in human serum was also corroborated, implying promising potential for glucose monitoring. Results demonstrated that the developed sensor provides new horizons for facile and sensitive glucose detection.
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Técnicas Biosensibles , Cobre , Glucemia , Automonitorización de la Glucosa Sanguínea , Electrodos , Glucosa , Humanos , Hidróxidos , Óxidos , Hojas de la PlantaRESUMEN
Telomerase is regarded as a crucial biomarker for the early diagnosis of malignant tumors and a valuable therapeutic target. In this work, a telomerase-triggered amplification strategy was designed on the basis of a catalyzed hairpin assembly (CHA) for bridging a signal probe of platinum nanoparticles (Pt NPs) anchored on three-dimensional (3D) epoxy-functionalized macroporous carbon (Pt/MPC-COOH) in an ultrasensitive electrochemical biosensor. Pt/MPC-COOH nanomaterials with interconnected macroporous structure not only immobilized hairpin DNA probe 2 (H2) via an amide reaction (Pt/MPC-COOH-H2), but they also generated an obvious electrochemical signal in response to acetaminophen (AP) oxidation. After the introduction of telomerase, telomerase primer (TP) was extended to a telomerase extension product (TEP) with several hexamer repeats (TTAGGG)n to initiate the CHA cycle, leading to signal amplification. Subsequently, with the TEP-triggered CHA cycle amplification strategy, a large amount of Pt/MPC-COOH-H2 was introduced on the electrode surface for the construction of the electrochemical platform, which realized the sensitive detection of telomerase activity from 102 to107 cells mL-1 with a limit of detection (LOD) of 9.02 cells mL-1. This strategy provides a sensitive method for the detection of biomolecules that could be useful for bioanalysis and early clinical diagnoses of diseases.
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Técnicas Biosensibles , Nanopartículas del Metal , Telomerasa , Carbono , Catálisis , Técnicas Electroquímicas , Límite de Detección , Platino (Metal) , Telomerasa/metabolismoRESUMEN
Coordination polymers are highly desirable for various applications due to their functionality control of crystal structures. In this work, an unique class of amorphous Co coordination polymer spheres anchored onto 3D macroporous carbon (MPC) support (denoted as Co CPSs/MPC) was prepared via a facile hydrothermal method. The formation of Co CPSs/MPC was systematically verified by a series of characterizations, like scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction, etc. The synergic effects between the superior electrical conductivity of 3D MPC supports and the excellent electrocatalytic activity of Co CPSs result in the increase of electron transfer from electrocatalyst, and then form significant number available reactive sites on the surface of electrode, which exhibit an exceptional catalytic activity and oxidation ability towards glucose. Under optimized conditions, amperometry results also indicated that the Co CPSs/MPC exhibit excellent electroanalysis towards glucose. The current work can shed light on the promising Co CPSs/MPC for further exploited as a sensitive and simple non-enzymatic glucose analytical platform.
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Transition metal doped carbon materials are recognized as promising sensing platforms for glucose detection. Herein, a simple strategy involving crystallinity, nanostructure engineering, and pyrolysis was developed for constructing well-defined Ni nanoparticle embedded on nanoporous carbon nanorods (Ni/NCNs). A three-dimensional nickel-based metal-organic framework (Ni-MOF) was used as both a self-sacrificing template and precursor. Due to the synergistic effects between the uniformly dispersed Ni nanoparticles and the nanoporous carbon matrix, the as-prepared Ni/NCNs exhibited remarkable electrochemical activity. The fabricated Ni/NCNs glucose sensor showed excellent electrocatalytic performance with ultra-low limit of detection, wide linear detection ranges, fast response times (within 1.6 s), superior stability, and anti-interference characteristics. Moreover, the Ni/NCNs sensing platform was successfully applied to analyze glucose concentrations in human blood samples. These results showed that Ni/NCNs hold potential applications in developing enzyme-free glucose sensors.
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Nanopartículas , Nanotubos , Carbono , Glucosa , Humanos , NíquelRESUMEN
MicroRNA-21 (miR-21) has been widely investigated as important biomarkers for cancer diagnosis and treatment. Herein, a highly sensitive nonenzymatic electrochemical biosensor based on Pd@metal-organic frameworks (Pd@UiO-66) and target-catalytic hairpin assembly (CHA) with target recycling approach has been proposed for the detection of miR-21. The proposed biosensor integrates the efficient CHA strategy and excellent electrocatalytic performance of Pd@UiO-66 nanocomposites. The concentration of miRNA-21 is related to the amount of the adsorbed electrocatalyst, leading to the different electrochemical signals for readout towards paracetamol (AP). This biosensor shows a low limit of detection of 0.713 fM with the dynamic range of 20 fM -600 pM under the optimal experimental conditions, providing a powerful platform for detecting miR-21. Furthermore, the designed biochemical self-assembly strategy of this electrochemical biosensor is promising candidate for potential applications in the analysis of other important genetic biomarkers for early diagnosis of cancers.
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Técnicas Biosensibles , Estructuras Metalorgánicas , MicroARNs , Catálisis , Técnicas Electroquímicas , Humanos , Límite de Detección , MicroARNs/análisisRESUMEN
The supramolecular construction of multi-stimuli assemblies is a challenging task for prospective use. In this work, a novel supramolecular amphiphile was fabricated by introducing molecules with dynamic covalent bonds into host-guest inclusion. The amphiphile formed a vesicle, which was characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), 1H NMR and UV-vis spectra. Furthermore, the vesicular structure could be regulated by pH, light and redox reagent, and thus the loaded dye in the vesicles could be released in a controlled manner.
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Compuestos Azo/química , Preparaciones de Acción Retardada/química , Tensoactivos/química , alfa-Ciclodextrinas/química , Carbocianinas/química , Composición de Medicamentos/métodos , Liberación de Fármacos , Colorantes Fluorescentes/química , Concentración de Iones de Hidrógeno , Cinética , Luz , Oxidación-Reducción , Pirenos/químicaRESUMEN
In order to fabricate a novel supra-amphiphile with multiple stimulus properties, we developed the strategy of introducing a bi-functional linker to bridge the hydrophilic and hydrophobic building blocks together, by utilizing more than one kind of interaction. We characterized the assembled structure and morphology of the supra-amphiphile using transmission electron microscopy (TEM), dynamic light scattering (DLS) and X-ray diffraction (XRD). 1H NMR and UV-vis spectroscopy studies revealed that the amphiphile was constructed by the effect of host-guest recognition and a dynamic covalent bond, which could be switched ''on'' and ''off'' via UV irradiation and pH variation stimuli, respectively. This responsiveness realized finely controllable self-assembly behaviors of the supra-amphiphile, which was thus able to encapsulate and release the drug model rhodamine B.