碳纳米管薄膜电极的制备及电容吸附性能

采用低压CVD法制备得到的金属镍基碳纳米管薄膜直接作为电容去离子器（CDD）的电极材料，并对碳纳米管薄膜进行了扫描电镜观察和比表面与孔径分析，探讨了该电极材料的电容吸附性能。NaF溶液的吸附实验结果表明：该电极材料的去离子效果明显、且可再生和重复使用。     

Sulfonated Graphene as Cation‐Selective Coating: A New Strategy for High‐Performance Membrane Capacitive Deionization

Membrane capacitive deionization (MCDI) featuring both high electrosorption capacity and high energy efficiency holds promise for desalination. However, the large‐scale applications of MCDI are limited greatly by the high cost of commercial ion‐exchange membranes and the interfacial resistance. Here, a new strategy for high‐performance MCDI is established using sulfonated graphene (SG) as cation‐selective coating. A continuous ultrathin SG coating via self‐assembly is formed and attached tightly onto the surface of electrospun carbon nanofibers (CNFs) by a simple yet effective dip‐coating technique, yielding SG‐CNF composites with a hydrophilic surface, high electrochemical specific capacitance, and greatly reduced interfacial charge transfer rate. These result in significantly enhanced capacitive deionization performance in terms of both electrosorption capacity and charge efficiency. The SG coating shows excellent cation selectivity for an asymmetric cell with SG–CNFs as a cathode. The new approach may pave a way to novel micro‐MCDI, i.e. novel applications of functional graphene‐based materials for high‐performance, energy‐efficient, and cost‐effective desalination.     

Rational Design of Carbon Nanomaterials for Electrochemical Sodium Storage and Capture

Electrochemical sodium storage and capture are considered an attractive technology owing to the natural abundance, low cost, safety, and cleanness of sodium, and the higher efficiency of the electrochemical system compared to fossil‐fuel‐based counterparts. Considering that the sodium‐ion chemistry often largely deviates from the lithium‐based one despite the physical and chemical similarities, the architecture and chemical structure of electrode materials should be designed for highly efficient sodium storage and capture technologies. Here, the rational design in the structure and chemistry of carbon materials for sodium‐ion batteries (SIBs), sodium‐ion capacitors (SICs), and capacitive deionization (CDI) applications is comprehensively reviewed. Types and features of carbon materials are classified into ordered and disordered carbons as well as nanodimensional and nanoporous carbons, covering the effect of synthesis parameters on the carbon structure and chemistry. The sodium storage mechanism and performance of these carbon materials are correlated with the key structural/chemical factors, including the interlayer spacing, crystallite size, porous characteristics, micro/nanostructure, morphology, surface chemistry, heteroatom incorporation, and hybridization. Finally, perspectives on current impediment and future research directions into the development of practical SIBs, SICs, and CDI are also provided.     

碳气凝胶的制备及其电除盐性能的研究

在常压条件下通过溶胶-凝胶法和碳化、活化工艺制备碳气凝胶材料.用SEM和BET比表面积测量等手段对材料的表面形貌和微观结构进行分析表征,通过循环伏安法对材料的电化学性能进行研究.联系材料的微观结构和电化学性能,对碳气凝胶的电除盐过程和除盐机理进行了研究和分析,发现碳气凝胶是一种具有很大应用潜力的多孔电极吸附材料.     

基于石墨烯及其复合物电极的电容去离子技术研究进展

电容去离子技术是一种高效节能、绿色环保的脱盐方法, 通过施加静电场, 强制离子向两侧电极迁移, 使其被电极表面产生的双电层吸附, 从而达到脱盐的目的。电容去离子技术的关键是高性能电极材料的制备, 要求具有较高的比表面积、合理的孔径分布和良好的导电性。石墨烯具有较高的理论比表面积和优异的导电性, 是一种理想的电极材料。然而由于石墨烯的聚集效应, 实际比表面积远远低于理论值, 将石墨烯制备成三维网络结构或将石墨烯与其他材料进行复合可以克服聚集效应, 提高电极的脱盐性能。本文综述了基于石墨烯及其复合物电极的电容去离子技术研究进展、存在的问题及应用前景。     

Designed fabrication of hierarchical porous carbon nanotubes/graphene/carbon nanofibers composites with enhanced capacitive desalination properties

Carbonaceous materials, one of the most important electrode materials for sea water desalination, have attracted tremendous attention. Herein, we develop a facile and effective two-step strategy to fabricate hierarchical porous carbon nanotubes/graphene/carbon nanofibers (CNTs/G/CNFs) composites for capacitive desalination application. Graphite oxide (GO), Ni²⁺, and Co²⁺ are introduced into polyacrylonitrile (PAN) nanofibers by electrospinning method. During the annealing process, the PAN nanofibers are carbonized into CNFs felt, while the CNTs grow in situ on the surface of CNFs and graphite oxide are reduced into graphene simultaneously. Benefiting from the unique hierarchical porous structure, the as-prepared CNTs/G/CNFs composites have a large specific surface area of 223.9 m² g^?1 and excellent electrical conductivity. The maximum salt capacity of the composites can reach to 36.0 mg g^?1, and the adsorbing capability maintains a large retention of 96.9% after five cycles. Moreover, the effective deionization time of the CNTs/G/CNFs composites lasts more than 30 min, much better than the commercial carbon fibers (C-CFs) and graphene/carbon nanofibers (G/CNFs) composites. Results suggest that the designed hierarchical porous CNTs/G/CNFs architecture could enhance the capacitive desalination properties of electrode materials. And the possible adsorption mechanism of the novel electrode materials is proposed as well.     

The effects of surface modification on the supercapacitive behaviors of carbon derived from calcium carbide

The capacitive behaviors of calcium-carbide-derived carbon (CCDC) before and after nitric acid (HNO₃) modification are investigated. The structure and morphology of the HNO₃-modified CCDC (M-CCDC) are examined by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The performances of the supercapacitor using M-CCDC as electrode active material are studied by cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy, and cycle life measurements. The results show that the capacitance of the supercapacitor increases from 154.7 to 196.5 F g⁻¹ and the capacitance decay is only 1.3% over 10,000 cycles for the M-CCDC, which exhibits higher capacitive performance than the pristine CCDC electrode in the aqueous electrolyte solution. The superiority of the M-CCDC in capacitance properties is caused by the variations of surface wettability and the interstitial pore structure of CCDC, which results from the introduction of polar oxygen functional groups onto the CCDC surface by HNO₃ modification.     

Unveiling Superior Capacitive Behaviors of One-Pot Molten Salt-Engineered B,N Co-Doped Porous Carbon Sheets

Heteroatom-doped porous carbon materials with distinctive surface properties and capacitive behavior have been accepted as promising candidates for supercapacitor electrodes. Currently, the researches mainly focus on developing facile synthetic method and unveiling the structure-activity relationship to further elevate their capacitive performance. Here, the B, N co-doped porous carbon sheet (BN-PCS) is constructed by one-pot pyrolysis of agar in KCl/KHCO₃ molten salt system. In this process, the urea acts as directing agent to guide the formation of 2D sheet morphology, and the decomposition of KHCO₃ and boric acid creates rich micro- and mesopores in the carbon framework. The specific capacitance of optimized BN-PCS reaches 361.1 F g⁻¹ at a current density of 0.5 A g⁻¹ in an aqueous KOH electrolyte. Impressively, the fabricated symmetrical supercapacitor affords a maximum energy density of 43.5 Wh kg⁻¹ at the power density of 375.0 W kg⁻¹ in 1.0 mol L⁻¹ TEABF₄/AN electrolyte. It also achieves excellent long-term stability with capacitance retention of 91.1% and Columbic efficiency of 100% over 10 000 cycles. This study indicates one-pot molten salt method is effective in engineering advanced carbon materials for high-performance energy storage devices.     

A Functionalized Carbon Surface for High‐Performance Sodium‐Ion Storage

Sodium‐ion batteries (SIBs) are promising for large‐scale energy storage systems and carbon materials are the most likely candidates for their electrodes. The existence of defects in carbon materials is crucial for increasing the sodium storage ability. However, both the reversible capacity and efficiency need to be further improved. Functionalization is a direct and feasible approach to address this issue. Based on the structural changes in carbon materials produced by surface functionalization, three basic categories are defined: heteroatom doping, grafting of functional groups, and the shielding of defects. Heteroatom doping can improve the electrochemical reactivity, and the grafting of functional groups can promote both the diffusion‐controlled bulk process and surface‐confined capacitive process. The shielding of defects can further increase the efficiency and cyclic stability without sacrificing reversible capacity. In this Review, recent progresses in the ways to produce surface functionalization are presented and the related impact on the physical and chemical properties of carbon materials is discussed. Moreover, the critical issues, challenges, and possibilities for future research are summarized.     

Dual‐Ion Electrochemical Deionization System with Binder‐Free Aerogel Electrodes

Desalination devices such as capacitive deionization (CDI) have been developed for many years as an approach to relief freshwater shortage. However, due to the limitation of physical adsorption capacity of CDI, the salt removal capacity is unable to reach high value. To enhance the desalination capacity effectively, battery materials are employed to fabricate a dual‐ion electrochemical deionization (DEDI) device. Herein, a binder‐free DEDI system with two free‐standing aerogel electrodes is reported. A Na₃V₂(PO₄)₃/graphene hybrid aerogel is used as sodium electrode and a AgCl/graphene hybrid aerogel is used as chloride electrode. With electric current passing through, sodium and chloride ions are released or absorbed by two aerogel electrodes. This system achieves super high desalination capacity, excellent cycling stability, and rapid desalination rate. The desalination capacity is as high as 107.5 mg g^?1 after 50 cycles with the current density of 100 mA g^?1. The outstanding desalination performance of this system shows a synergistic effect of combining battery materials with graphene for deionization and promises a new potential alternative of future desalination design.     

“Blockchain-Like” MIL-101(Cr)/Carbon Black Electrodes for Unprecedented Defluorination by Capacitive Deionization

Metal-organic frameworks (MOF) have attracted extensive attention due to their ultra-high specific surface area and tunable structure, the mechanism of direct utilization for capacitive deionization (CDI) defluorination remains undefined. Here, MIL-101(Cr) with ultra-high specific surface area, high water stability, and open metal sites (OMSs) is prepared by a hydrothermal method for defluorination of CDI. Carbon black is used as a “chain” to connect F-stored in the holes of MIL-101(Cr) (Cr-MOF)as “blocks” to enhance the conductivity and ion storage capacity of MIL-101(Cr)/carbon black electrodes (Cr-MOF electrodes). This simple construction method avoids the process complexity of in situ synthesis and performs better. These easily constructed “blockchain-like” Cr-MOF electrodes exhibit excellent defluorination capacity (39.84 mg_NaF g_electrodes⁻¹), low energy consumption (1.2 kWh kg_NaF⁻¹), and good stability. The coupling of the electrochemical redox reaction of Cr³⁺/Cr⁴⁺ with confined water is investigated using in situ and ex situ analysis methods combined with density functional theory (DFT), resulting in an unprecedented defluorination mechanism for Cr-MOF electrodes. This study opens up new ideas for the application of MOF in CDI, clarifies the removal mechanism of MOF, and lays a foundation for further promoting the application of raw materials with poor conductivity in the field of CDI.     

Surface Protection and Morphological Study of Copper by Green Corrosion Inhibitor: 8QSC in HNO<Subscript>3</Subscript> Medium

The inhibition performance and surface protection of green corrosion inhibitor 8-quinoline sulphonyl chloride (8QSC) on copper (Cu) was evaluated by chemical (weight loss) method in 0.5, 1.0 and 2.0 M HNO₃ solutions and by electrochemical methods such as potentiodynamic polarization (PDP), AC-impedance spectroscopy (AC-IS) and linear polarization resistance in 1.0 M HNO₃ solution at room temperature. Both chemical and electrochemical techniques showed that 8QSC is an efficient green corrosion inhibitor for copper and the efficiency reached 90.4% by weight loss method and 88.4% by AC-IS method at optimum concentration of (300 ppm) 8QSC. The adsorption behavior of 8QSC on copper metal in acid medium obeyed the Langmuir isotherm. The thermodynamic parameters of the adsorption processes were calculated and discussed. AC-IS technique exhibits one capacitive loop, indicating that the corrosion reaction was controlled by charge transfer process. The PDP curves revealed that 8QSC acts as a mixed-type inhibitor. Protective layer of 8QSC on copper surface was examined by SEM, AFM and FT-IR techniques. The experimental results corroborated with results obtained from theoretical DFT studies.     

不同催化剂作用下生长的碳纳米管和碳纳米纤维复合膜的电吸附性能(英文)

采用低压低温气相沉淀法在不同催化剂(Fe和Ni)作用下制备碳纳米管-碳纤维复合薄膜,并研究其电容去离子行为,结果表明:在Ni催化作用下石墨上生长的碳纳米复合薄膜电极的去离子能力比Fe催化作用下生长的碳纳米复合薄膜电极的强;并且碳纳米复合薄膜的电吸附遵循langmuir单层等温吸附.     

Removal of nitroimidazole antibiotics from aqueous solution by adsorption/bioadsorption on activated carbon

The objective of the present study was to analyse the behaviour of activated carbon with different chemical and textural properties in nitroimidazole adsorption, also assessing the combined use of microorganisms and activated carbon in the removal of these compounds from waters and the influence of the chemical nature of the solution (pH and ionic strength) on the adsorption process. Results indicate that the adsorption of nitroimidazoles is largely determined by activated carbon chemical properties. Application of the Langmuir equation to the adsorption isotherms showed an elevated adsorption capacity (X_m = 1.04–2.04 mmol/g) for all contaminants studied. Solution pH and electrolyte concentration did not have a major effect on the adsorption of these compounds on activated carbon, confirming that the principal interactions involved in the adsorption of these compounds are non-electrostatic. Nitroimidazoles are not degraded by microorganisms used in the biological stage of a wastewater treatment plant. However, the presence of microorganisms during nitroimidazole adsorption increased their adsorption on the activated carbon, although it weakened interactions between the adsorbate and carbon surface. In dynamic regime, the adsorptive capacity of activated carbon was markedly higher in surface water and groundwater than in urban wastewaters.     

Potentiodynamical co-deposited manganese oxide/carbon composite for high capacitance electrochemical capacitors

Manganese oxide/carbon composite materials were prepared by introducing the carbon powders into the potentiodynamical anodic co-deposited manganese oxide in 0.5 mol L^− 1 MnSO₄ and 0.5 mol L^− 1 H₂SO₄ mixed solution at 40 °C. The surface morphology and structure of the composite material were examined by scanning electron microscope and X-ray diffraction. Cyclic voltammetry tests and electrochemical impedance measurements were applied to investigate the performance of the composite electrodes with different ratios of manganese oxide and carbon. These composite materials with rough surface, which consisted of approximately amorphous manganese oxide, were confirmed to possess the ideal capacitive property. The highest specific capacitance of manganese oxide/carbon composite electrode was up to 410 F g^− 1 in 1.0 mol L^− 1 Na₂SO₄ electrolyte at the scan rate 10 mV s^− 1. The synthesized composite materials exhibited ideal capacitive behavior indicating a promising electrode material for electrochemical supercapacitors.     

Synthesis of polyaniline-coated ordered mesoporous carbon and its enhanced electrochemical properties

Pore surface of ordered mesoporous carbon (OMC) was coated with a thin layer of polyaniline by chemical polymerization of aniline monomers. Structure characterizations, such as N₂ adsorption analysis, small angle X-ray diffraction and transmission electron microscopy, demonstrate that polyaniline is well distributed on the pore surface of OMC. As evidenced by constant current charge–discharge test, specific capacitance of polyaniline-coated ordered mesoporous carbon (PCOMC) reaches as high as 602.5 F/g, which is much higher than that of OMC, due to the incorporation of polyaniline onto the pore surface of OMC. However, the capacitive behavior deteriorated somewhat due to the narrowed pore size and extra faradiac reactions caused by the incorporation of polyaniline.     

Rational synthesis of carbon shell coated polyaniline/MoS<Subscript>2</Subscript> monolayer composites for high-performance supercapacitors

Conducting polymers generally show high specific capacitance but suffer from poor rate capability and rapid capacitance decay, which greatly limits their practical applications in supercapacitor electrodes. To this end, many studies have focused on improving the overall capacitive performance by synthesizing nanostructured conducting polymers or by depositing a range of coatings to increase the active surface area exposed to the electrolyte and enhance the charge transport efficiency and structural stability. Despite this, simultaneously achieving high specific capacitance, good rate performance, and long cycle life remains a considerable challenge. Among the various two-dimensional (2D) layered materials, octahedral (1T) phase molybdenum disulfide (MoS₂) nanosheets have high electrical conductivity, large specific surface areas, and unique surface chemical characteristics, making them an interesting substrate for the controlled growth of nanostructured conducting polymers. This paper reports the rational synthesis of carbon shell-coated polyaniline (PANI) grown on 1T MoS₂ monolayers (MoS₂/PANI@C). The composite electrode comprised of MoS₂/PANI@C with a ~3 nm carbon shell exhibited a remarkable specific capacitance of up to 678 F·g^–1 (1 mV·s^–1), superior capacity retention of 80% after 10,000 cycles and good rate performance (81% at 10 mV·s^–1) due to the multiple synergic effects between the PANI nanostructure and 1T MoS₂ substrates as well as protection by the uniform thin carbon shell. These properties are comparable to the best overall capacitive performance achieved for conducting polymers-based supercapacitor electrodes reported thus far.

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Nanostructured materials for water desalination

Desalination of seawater and brackish water is becoming an increasingly important means to address the scarcity of fresh water resources in the world. Decreasing the energy requirements and infrastructure costs of existing desalination technologies remains a challenge. By enabling the manipulation of matter and control of transport at nanometer length scales, the emergence of nanotechnology offers new opportunities to advance water desalination technologies. This review focuses on nanostructured materials that are directly involved in the separation of water from salt as opposed to mitigating issues such as fouling. We discuss separation mechanisms and novel transport phenomena in materials including zeolites, carbon nanotubes, and graphene with potential applications to reverse osmosis, capacitive deionization, and multi-stage flash, among others. Such nanostructured materials can potentially enable the development of next-generation desalination systems with increased efficiency and capacity.     

Effects of carbon content on the photocatalytic activity of C/BiVO4 composites under visible light irradiation

Carbon-loaded BiVO₄ composite photocatalysts were prepared using an impregnation method, and their ability to photocatalytically degrade Rhodamine B dye solution under visible light irradiation was investigated. The prepared composite photocatalysts were characterized by X-ray diffraction (XRD), field-emission electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) surface area measurements, and UV–vis diffuse reflectance spectra. We found that the carbon was well-dispersed on the surface of BiVO₄. The photocatalytic activity of the composite photocatalysts for the degradation of Rhodamine B (RhB) in aqueous solution under visible light irradiation (>420 nm) was higher than that of pure BiVO₄. Moreover, the degradation efficiency increased as the carbon content increased up to 3 wt%. The mechanism of enhanced photocatalytic activity is discussed with reference to surface area, optical absorption properties, and charge separation.     

A 2D Titanium Carbide MXene Flexible Electrode for High-Efficiency Light-Emitting Diodes

Although several transparent conducting materials such as carbon nanotubes, graphene, and conducting polymers have been intensively explored as flexible electrodes in optoelectronic devices, their insufficient electrical conductivity, low work function, and complicated electrode fabrication processes have limited their practical use. Herein, a 2D titanium carbide (Ti₃C₂) MXene film with transparent conducting electrode (TCE) properties, including high electrical conductivity (≈11 670 S cm⁻¹) and high work function (≈5.1 eV), which are achieved by combining a simple solution processing with modulation of surface composition, is described. A chemical neutralization strategy of a conducting-polymer hole-injection layer is used to prevent detrimental surface oxidation and resulting degradation of the electrode film. Use of the MXene electrode in an organic light-emitting diode leads to a current efficiency of ≈102.0 cd A⁻¹ and an external quantum efficiency of ≈28.5% ph/el, which agree well with the theoretical maximum values from optical simulations. The results demonstrate the strong potential of MXene as a solution-processable electrode in optoelectronic devices and provide a guideline for use of MXenes as TCEs in low-cost flexible optoelectronic devices.