Traditional Carbon Materials Research Articles

Nitrogen-doped porous carbon skeleton derived from glycine boosting superior rate capability and long lifespan for Na3V2(PO4)3 with high thermal safety

Currently, the both low electronic and ionic conductivity have seriously hindered the further application of Na3V2(PO4)3 (NVP). Nevertheless, traditional carbon materials modification only improves the electronic conductive property, rather than modifying the ionic conductivity. Herein, N-rich carbon resources of glycine (GLY) is introduced to synthesize NVP, which can act as reducing agent and morphology inducer to optimize NVP sample. Notably, GLY supplies favorable N-doped carbon skeleton, and this defective carbon structure benefits for the accelerated electronic conductivity. Besides, porous construction is established after introducing GLY. This unique morphology significantly improves the infiltration effects of electrolyte, thus providing more electrochemical active sites for Na+ de-intercalation to improve the ionic conductivity. Meanwhile, porous framework supplies enough space for the shrinkage of crystal cells, so the stress-strain effect is highly restrained, which is demonstrated by Ex-situ XRD. The stabilized crystal and morphological structure of NVP@GLY-2 has been verified by after-cycled XRD/SEM/XPS. Highly improved kinetic characteristics are also investigated by In-situ EIS. Moreover, Accelerating Rate Calorimeter (ARC) measurements indicate that NVP@GLY-2-based half and full cells also have excellent thermal safety properties. Comprehensively, NVP@GLY-2 reveals a high capacity of 119 mAh g−1 at 0.1 C. It reveals 84.5 and 71.2 mAh g−1 at 10 and 50 C, with capacity retention rates of 88.9 % and 85.8 % after 1000 cycles.

Design of Silicon-Based Anode Materials for High Energy Density Li-Ion Batteries

Compared to other types of batteries, lithium batteries have an extremely high energy density, which means they can store more energy while maintaining a smaller size and weight. The ideal electrode material must have a high lithium ion capacity to store many lithium ions. In addition, the electrode material must have good electronic conductivity to promote lithium ions' rapid entry and exit. However, traditional carbon materials have limited theoretical specific capacity, and the transmission of lithium-ion batteries in traditional materials is limited, resulting in a significant decrease in capacity. Silicon has a theoretical capacity of up to 4200mAh/g, more than ten times the capacity of commercial graphite negative electrodes. In addition, silicon and lithium can undergo alloying reactions to form Li Si alloys, which helps improve the material's specific capacity. This article first summarizes the advantages of electric vehicles and lithium-ion batteries. Then, the benefits and challenges of using silicon-based materials as negative electrodes for lithium-ion batteries were elaborated in detail, and finally, the prospects of silicon-based materials in lithium-ion battery applications were summarized. This article has reference significance in improving the energy density of lithium-ion batteries.

Preparation of nano Cu-Mo2C interface supported on ordered mesoporous biochar of ultrahigh surface area for reverse water gas shift reaction

High conversion rate and selectivity are challenges for CO2 utilization through catalytic reverse water gas shift (RWGS) reaction. Herein, a novel mesoporous biochar (MB) supported Cu-Mo2C nano-interface was prepared by consecutive physical activation of coconut shells followed by carbothermal hydrogen reduction of bimetal. As compared with traditional carbon materials, this MB exhibited ultra-high specific surface area (2693 m2 g–1) and mesopore volume of mesopore (0.81 cm3 g–1) with a narrow distribution (2–5 nm), responsible for the high dispersion of binary Cu-Mo2C sites, CO2 adsorption and mass transfer in the reaction system. Moderate carbothermal reduction led to the sufficient reduction of Mo ion with carbon matrix of MB and dispersive growth of nano Cu-Mo2C binary sites (~ 6.1 nm) on the surface of MB. Cu+ species were formed from Cu0 via electron transfer and showed high dispersion with simultaneous boosted bimetal loading due to the strong interaction between nano Mo2C and Cu. These were advantageous to the intrinsic activity and stability of the Cu-Mo2C binary sites and their accessibility to the reactant molecules. Under the RWGS reaction conditions of 500 °C, atmospheric pressure, and 300,000 ml/g/h gas hour space velocity, the CO2 conversion rate over Cu-Mo2C/MB reached 27.74 × 10–5 molCO2/gcat/s at very low H2 partial pressure, which was more than twice that over traditional carbon supported Cu-Mo2C catalysts. In addition, this catalyst exhibited 99.08% CO selectivity and high stability for more than 50 h without a decrease in activity and selectivity. This study offers a new development strategy and a promising candidate for industrial RWGS.Graphical

Development of self-sensing cement composites by incorporating hybrid biochar and nano carbon black

The self-sensing cement composites (SSCC) containing traditional conductive carbon materials are of great significance but cause serious pollution. In this study, the green SSCC is innovatively developed utilizing the synergistic effects of nano carbon black and biochar from coconut shell. The SSCC mixtures are compared in terms of fluidity, mechanical properties, resistivity, microstructure and comprehensive properties. The results indicate that in SSCC containing nano carbon black, the addition of biochar can obtain comparable compressive strength for its internal curing, interlocking and bridging effects. Besides, 4.5 % carbon material prolongs the crack initiation stage during compression, and 9 % carbon material causes the multiple cracks. Moreover, the addition of 4.5 % biochar can reduce the 35-day resistivity of sample with 1.5 % biochar and 3 % nano carbon black by 35.6 % owing to the increasing tunneling effect and contact conduction. It is also found that in conductive SSCC, the slope Kc of the non-contact resistivity curve is dominated by the conductive additives rather than cement hydration. And the self-sensing cement composites exhibit excellent piezoresistivity. The rates of change in resistivity of samples after cycle loading are exponentially related to residual damages, with R2 values greater than 0.95. Finally, multi-indicator evaluation analyses show that the sample containing more biochar is more environmentally friendly. This study provides a new pathway for the sustainable development of SSCC.

High-Performance Supercapacitors Using Compact Carbon Hydrogels Derived from Polybenzoxazine.

Polybenzoxazine (PBz) aerogels hold immense potential, but their conventional production methods raise environmental and safety concerns. This research addresses this gap by proposing an eco-friendly approach for synthesizing high-performance carbon derived from polybenzoxazine. The key innovation lies in using eugenol, ethylene diamine, and formaldehyde to create a polybenzoxazine precursor. This eliminates hazardous solvents by employing the safer dimethyl sulfoxide. An acidic catalyst plays a crucial role, not only in influencing the microstructure but also in strengthening the material's backbone by promoting inter-chain connections. Notably, this method allows for ambient pressure drying, further enhancing its sustainability. The polybenzoxazine acts as a precursor to produce two different carbon materials. The carbon material produced from the calcination of PBz is denoted as PBZC, and the carbon material produced from the gelation and calcination of PBz is denoted as PBZGC. The structural characterization of these carbon materials was analyzed through different techniques, such as XRD, Raman, XPS, and BET analyses. BET analysis showed increased surface of 843 m2 g-1 for the carbon derived from the gelation method (PBZGC). The electrochemical studies of PBZC and PBZGC imply that a well-defined morphology, along with suitable porosity, paves the way for increased conductivity of the materials when used as electrodes for supercapacitors. This research paves the way for utilizing heteroatom-doped, polybenzoxazine aerogel-derived carbon as a sustainable and high-performing alternative to traditional carbon materials in energy storage devices.

High-Performance Supercapacitor Electrodes from Fully Biomass-Based Polybenzoxazine Aerogels with Porous Carbon Structure.

In recent years, polybenzoxazine aerogels have emerged as promising materials for various applications. However, their full potential has been hindered by the prevalent use of hazardous solvents during the preparation process, which poses significant environmental and safety concerns. In light of this, there is a pressing need to explore alternative methods that can mitigate these issues and propel the practical utilization of polybenzoxazine aerogels. To address this challenge, a novel approach involving the synthesis of heteroatom self-doped mesoporous carbon from polybenzoxazine has been devised. This process utilizes eugenol, stearyl amine, and formaldehyde to create the polybenzoxazine precursor, which is subsequently treated with ethanol as a safer solvent. Notably, the incorporation of boric acid in this method serves a dual purpose: it not only facilitates microstructural regulation but also reinforces the backbone strength of the material through the formation of intermolecular bridged structures between polybenzoxazine chains. Moreover, this approach allows ambient pressure drying, further enhancing its practicability and environmental friendliness. The resultant carbon materials, designated as ESC-N and ESC-G, exhibit distinct characteristics. ESC-N, derived from calcination, possesses a surface area of 289 m2 g-1, while ESC-G, derived from the aerogel, boasts a significantly higher surface area of 673 m2 g-1. Furthermore, ESC-G features a pore size distribution ranging from 5 to 25 nm, rendering it well suited for electrochemical applications such as supercapacitors. In terms of electrochemical performance, ESC-G demonstrates exceptional potential. With a specific capacitance of 151 F g-1 at a current density of 0.5 A g-1, it exhibits superior energy storage capabilities compared with ESC-N. Additionally, ESC-G displayed a more pronounced rectangular shape in its cyclic voltammogram at a low voltage scanning rate of 20 mV s-1, indicative of enhanced electrochemical reversibility. The impedance spectra of both carbon types corroborated these findings, further validating the superior performance of ESC-G. Furthermore, ESC-G exhibits excellent cycling stability, retaining its electrochemical properties even after 5000 continuous charge-discharge cycles. This robustness underscores its suitability for long-term applications in supercapacitors, reaffirming the viability of heteroatom-doped polybenzoxazine aerogels as a sustainable alternative to traditional carbon materials.

Degradation of Bisphenol A by Nitrogen-Rich ZIF-8-Derived Carbon Materials-Activated Peroxymonosulfate.

Bisphenol A (BPA), representing a class of organic pollutants, finds extensive applications in the pharmaceutical industry. However, its widespread use poses a significant hazard to both ecosystem integrity and human health. Advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) via heterogeneous catalysts are frequently proposed for treating persistent pollutants. In this study, the degradation performance of BPA in an oxidation system of PMS activated by transition metal sites anchored nitrogen-doped carbonaceous substrate (M-N-C) materials was investigated. As heterogeneous catalysts targeting the activation of peroxymonosulfate (PMS), M-N-C materials emerge as promising contenders poised to overcome the limitations encountered with traditional carbon materials, which often exhibit insufficient activity in the PMS activation process. Nevertheless, the amalgamation of metal sites during the synthesis process presents a formidable challenge to the structural design of M-N-C. Herein, employing ZIF-8 as the precursor of carbonaceous support, metal ions can readily penetrate the cage structure of the substrate, and the N-rich linkers serve as effective ligands for anchoring metal cations, thereby overcoming the awkward limitation. The research results of this study indicate BPA in water matrix can be effectively removed in the M-N-C/PMS system, in which the obtained nitrogen-rich ZIF-8-derived Cu-N-C presented excellent activity and stability on the PMS activation, as well as the outstanding resistance towards the variation of environmental factors. Moreover, the biological toxicity of BPA and its degradation intermediates were investigated via the Toxicity Estimation Software Tool (T.E.S.T.) based on the ECOSAR system.

Application of carbon nanotubes in lithium-ion batteries

Battery demand as a power source has skyrocketed due to the electric car market’s explosive growth. Because of its high energy density, lack of memory effect, low self-discharge rate, environmental friendliness, and extended cycle life, lithium-ion batteries, or LIBs, are widely employed in electric cars, aircraft, and other sectors. However, the use of traditional carbon materials in LIBs has led to relatively low specific capacity, limited charging and discharging rates, and low first-time charging and discharging efficiencies Carbon nanotubes (CNTs), with their high electrical conductivity, excellent mechanical properties, and thermal conductivity, can bring higher capacity, better cycling stability, excellent thermal conductivity, as well as lightweight and flexibilization to LIBs. Therefore, this paper first introduces the basic properties of CNTs and their preparation methods. Then, their roles in the positive and negative electrodes of LIBs are discussed respectively. Finally, an outlook on the future development of LIBs is made. This has a reference value for the future development of LIBs.

Study of high conductivity electrode for superior performance lithium-ion batteries based on low tortuosity corn straw biochar/VS4 with multichannel structure

It is an effective measure to achieve the application agricultural waste and the development of sustainable energy by effectively utilizing the corn straw with natural multichannel structure in electrochemical energy storage devices. Corn straw biochar as a sustainable and environmentally friendly form of clean energy, serves as a carbon-based material in electrode of lithium-ion batteries. The natural multi-channels and sieve tube structure is the foundation for the electrode with low tortuosity. Within the traditional carbon materials, these characteristics are not commonly presented. In this study, a strategy is proposed to boost the performance of the electrode by devising and modifying its structure. The multichannel and porous structure within the electrodes is achieved by leveraging the natural structure of corn straw. This unique structure can bring low tortuosity in the electrode, thereby facilitating the construction of the direct ions transfer channels and continuous electrons pathways. Moreover, the inherent nitrogenous feature of biochar result in enhanced surface polarity, enabling the electrode material to trap the polar polysulfides efficiently. Additionally, the multichannel and porous structure of electrode also bring sufficient space to accommodate volume expansion, thereby improving the stability of electrode. Therefore, this work points an effective approach to harnessing the potential of corn straw and also constructing an electrode with a multichannel and porous structure and low tortuosity, ultimately enhancing the electrochemical performance for lithium batteries.

A Facile Molten Salt Method for Diverse TiC/C Hybrid as Effective Polysulfide Confinement toward Stable Lithium–Sulfur Batteries

Traditional carbon materials suffer from weak adsorption of lithium polysulfides and excessive consumption of electrolyte. A simple and feasible molten salt method is applied for constructing an active nanocrystalline TiC shell on the surface of porous carbon. The highly active TiC nanoshells endow the core–shell composite with efficient chemical–physical synergistic adsorption, which can effectively confine and convert polysulfides, thereby improving the electrochemical performance of lithium–sulfur batteries. The lithium–sulfur batteries assembled with modified separator deliver a high initial discharge specific capacity of 1396 mAh g−1 at a discharge rate of 0.5 C and a high capacity retention of 747.1 mAh g−1 after 500 cycles, with a high coulombic efficiency of 98% during cycling. Besides, this molten salt method can be applied to modify the porous carbon materials of various composite sulfur cathodes such as graphene, carbon nanotubes, and 3D nonwoven carbon fabrics.

Recent Developments and Emerging Opportunities for Biomass Derived Carbon Materials in Dye Sensitized Solar Energy Conversion

AbstractTo meet the ever‐increasing demand for solar energy conversion, the exploration of new materials that improve energy and cost efficiency is great significance. Particularly in dye‐sensitized solar cells, extensive efforts have been made to substitute the traditional metal‐based components with various carbon materials. As the result, carbon materials such as carbon dots, carbon nanotubes, grapheme, and porous carbon materials are explored for their components, which are traditionally derived from fossil resources. Recently these carbon materials are widely synthesized or derived from renewable biomasses and getting important in solar energy conversion due to their similar structural, physicochemical, morphological, and functional features of above stated traditional carbon materials. The utilization of these biocarbon materials offers numerous environmental and economic benefits over traditional carbon materials and creates a new pathway towards a sustainable future. Thus, this review summarizes the recent exploration of biocarbon materials in dye‐sensitized solar cells and discusses their emerging opportunities.

Graphene-like structure of bio-carbon with CoFe Prussian blue derivative composites for enhanced microwave absorption

Traditional carbon materials such as graphene are often applied in the field of electromagnetic wave (EMW) absorption but they have unbalanced impedance matching and high conductivity. Bio-carbon with graphene-like structure derived from apples has many advantages over graphene: it can be prepared in large quantities and the abundant heteroatoms present in the lattice can provide many polarization phenomena. Herein, Prussian blue analogue (PBA) as a source of magnetic component was combined with bio-carbon or reduced graphene oxide (rGO) to study the EMW absorption properties. The fabricated BC/CFC-12-7 displayed performance with a minimum reflection loss (RLmin) of −72.57 dB and a wide effective absorption bandwidth (EAB) of 5.25 GHz with an ultra-thin and nearly equal matching thickness at 1.61 mm. The results show that the good EMW absorption property of bio-carbon composites comes from good conduction loss, large relaxation polarization loss especially from pyridinic-N, and better impedance matching. The optimized radar cross section is found to be –33.55 dB m2 in the far-field condition using CST. This work explored the advantages of bio-carbon as a novel EMW absorbing material compared with graphene and provided ideas for realizing high-performance EMW absorbing materials in the future.

Paper-Derived Carbon Electrodes, a Versatile Option to Develop Electrochemical Sensors

Carbon-based materials are particularly well-suited for electroanalytical applications due to their distinct properties, such as high chemical stability, large electroactive areas, wide electrochemical potential window in aqueous solutions, low electrical resistance, rich surface chemistry, and activity towards a variety of redox reactions. While carbon electrodes can be produced via thermal decomposition of gaseous hydrocarbons followed by their surface-induced recombination, this method is not cost-effective and suffers from both low efficiency (~20%) and limited selectivity towards graphitic forms. Alternatively, carbon electrodes can be developed via pyrolytic treatment of non-volatile substrates. This approach yields carbon materials that are rich in graphitic phases and provides researchers a much richer selection of starting materials and source-to-product efficiencies ~70%. Our team has applied this approach to develop several optically transparent carbon electrodes and has described a method for fabricating carbon electrodes by pyrolysis of paper, using a tube furnace and under a mild reducing atmosphere. The resulting electrodes not only feature the properties of traditional carbon materials but also preserve the 3D structure of the starting material, are mildly hydrophobic, and offer a wide electrochemical window and can be patterned using laser engraving. Moreover, the process also enables the incorporation of metallic nanoparticles within the structure of the material (by pyrolyzing paper pre-soaked in a solution containing the selected cation), significantly improving the conductivity of the material. Thus, this presentation will provide a brief summary of the reactions leading to the fabrication of these substrates as well as discuss the most recent applications towards their use as sensors in microfluidic devices.Special emphasis will be placed on the use of these electrodes for the detection of S. aureus, application that required the modification of the material with a thin layer of sputtered gold (that minimizes lateral resistivity and significantly improves the electron transfer process) and with chitosan (used as a binder to offer flexibility). This biosensor was controlled using a custom-built potentiostat (via a wireless connection), which was used to detect the presence of the bacteria via the oxidation of the ferrocyanide (produced by the bacteria’s respiration cycle) in the presence of mannitol.More information about the group can be found in our web site scienceweb.clemson.edu/uacl/

Two-Dimensional Carbon Graphdiyne: Advances in Fundamental and Application Research.

Graphdiyne (GDY), a rising star of carbon allotropes, features a two-dimensional all-carbon network with the cohybridization of sp and sp2 carbon atoms and represents a trend and research direction in the development of carbon materials. The sp/sp2-hybridized structure of GDY endows it with numerous advantages and advancements in controlled growth, assembly, and performance tuning, and many studies have shown that GDY has been a key material for innovation and development in the fields of catalysis, energy, photoelectric conversion, mode conversion and transformation of electronic devices, detectors, life sciences, etc. In the past ten years, the fundamental scientific issues related to GDY have been understood, showing differences from traditional carbon materials in controlled growth, chemical and physical properties and mechanisms, and attracting extensive attention from many scientists. GDY has gradually developed into one of the frontiers of chemistry and materials science, and has entered the rapid development period, producing large numbers of fundamental and applied research achievements in the fundamental and applied research of carbon materials. For the exploration of frontier scientific concepts and phenomena in carbon science research, there is great potential to promote progress in the fields of energy, catalysis, intelligent information, optoelectronics, and life sciences. In this review, the growth, self-assembly method, aggregation structure, chemical modification, and doping of GDY are shown, and the theoretical calculation and simulation and fundamental properties of GDY are also fully introduced. In particular, the applications of GDY and its formed aggregates in catalysis, energy storage, photoelectronic, biomedicine, environmental science, life science, detectors, and material separation are introduced.

A universal strategy for green synthesis of biomass-based transition metal single-atom catalysts by simple hydrothermal and compression treatment

Carbon-based single-atom catalysts (SACs) have attracted increasing extensive attention due to their excellent catalytic performance and high atomic utilization efficiency. Traditional porous carbon materials are not suitable supports for SACs synthesis owing to the inert surface and heteroatoms such as N and S are necessarily introduced as increased anchoring sites for single metal atoms. Herein, we reported a novel universal strategy to synthesize carbon-based transition metal (Fe, Co, Ni, Cu, and Zn) SACs by one-pot hydrothermal treatment combined with a mechanochemical method by virtue of abundant active oxygen naturally in biomass feedstock. The hydrothermal treatment resulted in relatively monodispersed metal ions within the carbonaceous matrix and compression process played a vital role in the formation and anchoring of the single atom, preventing self-aggregation during pyrolysis by confinement effect. The characterization results showed the metal atoms were atomically dispersed on carbon support in the form of M-O3C coordination and had relatively high metal contents of up to 1.15 wt%. Due to the in-situ formation, unique coordination surroundings, and high content of metal atoms, the prepared catalyst exhibited excellent reactivity performance. This work demonstrated the sustainability and economic feasibility of carbon-based SACs synthesis simultaneously by co-using natural oxygen as anchoring sites and abundant carbon as the skeleton in biomass feedstock and offered a novel approach for high-value utilization of biomass.

Design of Uniform Hollow Carbon Nanoarchitectures: Different Capacitive Deionization between the Hollow Shell Thickness and Cavity Size.

Carbon-based materials with high capacitance ability and fast electrosorption rate are ideal electrode materials in capacitive deionization (CDI). However, traditional carbon materials have structural limitations in electrochemical and desalination performance due to the low capacitance and poor transmission channel of the prepared electrodes. Therefore, reasonable design of electrode material structure is of great importance for achieving excellent CDI properties. Here, uniform hollow carbon materials with different morphologies (hollow carbon nanospheres, hollow carbon nanorods, hollow carbon nano-pseudoboxes, hollow carbon nano-ellipsoids, hollow carbon nano-capsules, and hollow carbon nano-peanuts) are reasonably designed through multi-step template method and calcination of polymer precursors. Hollow carbon nanospheres and hollow carbon nano-pseudoboxes exhibit better capacitance and higher salt adsorption capacity (SAC) due to their stable carbonaceous structure during calcination. Moreover, the effects of the thickness of the shell and the size of the cavity on the CDI performance are also studied. HCNSs-0.8 with thicker shell (≈20nm) and larger cavity (≈320nm) shows the best SAC value of 23.01mgg-1 due to its large specific surface area (1083.20m2 g-1 ) and rich pore size distribution. These uniform hollow carbon nanoarchitectures with functional properties have potential applications in electrochemistry related fields.

Electronic Oxide-Support Strong Interactions in the Graphdiyne-Supported Cuprous Oxide Nanocluster Catalyst.

The interfacial interaction in supported catalysts is of great significance for heterogeneous catalysis because it can induce charge transfer, regulate electronic structure of active sites, influence reactant adsorption behavior, and eventually affect the catalytic performance. It has been theoretically and experimentally elucidated well in metal/oxide catalysts and oxide/metal inverse catalysts, but is rarely reported in carbon-supported catalysts due to the inertness of traditional carbon materials. Using an example of a graphdiyne-supported cuprous oxide nanocluster catalyst (Cu2O NCs/GDY), we herein demonstrate the strong electronic interaction between them and put forward a new type of electronic oxide-graphdiyne strong interaction, analogous to the concept of electronic oxide/metal strong interactions in oxide/metal inverse catalysts. Such electronic oxide-graphdiyne strong interaction can not only stabilize Cu2O NCs in a low-oxidation state without aggregation and oxidation under ambient conditions but also change their electronic structure, resulting in the optimized adsorption energy for reactants/intermediates and thus leading to improved catalytic activity in the Cu(I)-catalyzed azide-alkyne cycloaddition reaction. Our study will contribute to the comprehensive understanding of interfacial interactions in supported catalysts.

Thermopressure Coupling Effect Mimicking Natural Graphite Formation to Enhance the Storage K-Ion Performance of Carbonaceous Heterostructures.

Borrowing from natural mechanisms for material design can lead to functional mimicry and improvement. Inspired by graphite formation, a thermopressure coupling strategy under micropressure (<400 Pa) is applied to prepare carbon anodes. A thermopressure response is discovered based on the cellulose precursor. Here, homologous graphene quantum dot/hard carbon (GQD/HC) heterostructures are synthesized. Under 181.4 Pa and 1,200 °C, the product shows a capacity of 310 mAh g-1, while the capacity of the direct carbonization product is only 120 mAh g-1. Prominently, the GQD/HC heterostructure displays marked mechanical strength and flexibility. The experimental and theoretical results illustrate the ion and electron transfer, coordination environment, and electronic states in the GQD/HC heterostructure and elaborate on the origin of the enhanced performance. The thermopressure coupling under micropressure mimics graphite formation, but the heterostructure has better properties than traditional carbon materials. Additionally, micropressure injects new vitality into material research.

Revealing the Mechanism of sp-N Doping in Graphdiyne for Developing Site-Defined Metal-Free Catalysts.

Due to the limited reserves of metals, scientists are devoted to exploring high-performance metal-free catalysts based on carbon materials to solve environment-related issues. Doping would build up inhomogeneous charge distribution on surface, which is an efficient approach for boosting the catalytic performance. However, doping sites are difficult to control in traditional carbon materials, thus hindering their development. Taking the advantage of unique sp-C in graphdiyne (GDY), a new N doping configuration of sp-hybridized nitrogen (sp-N), bringing a Pt-comparable catalytic activity in oxygen reduction reaction is site-defined introduced. However, the reaction intermediate of this process is never captured, hindering the understanding of the mechanism and the precise synthesis of metal-free catalysts. After the four-year study, the fabrication of intermediate-like molecule is realized, and finally sp-N doped GDY via the pericyclic reaction is obtained. Compared with GDY doped with other N configurations, the designed sp-N GDY shows much higher catalytic activity in electroreduction of CO2 toward CH4 production, owing to the unique electronic structure introduced by sp-N, which is more favorable in stabilizing the intermediate. Thus, besides opening the black-box for the site-defined doping, this work reveals the relationship between doping configuration and products of CO2 reduction.

Research progress on the application of derived porous carbon materials in solid-phase microextraction

固相微萃取是一种集采样、萃取、富集和进样于一体的样品前处理技术,其萃取效果与涂层材料密切相关。多孔碳材料具有比表面积大、多孔结构可控、活性位点多和化学稳定性好等优点,广泛应用于电池、超级电容器、催化、吸附和分离等领域,也是一种热门的用作固相微萃取探针的涂层材料。衍生多孔碳材料因种类丰富、可设计性强被广泛研究,研究主要集中在对衍生多孔碳材料的结构优化方面。但是衍生多孔碳材料在固相微萃取中的应用还存在如下问题:(1)共价有机框架衍生多孔碳材料的制备已取得较大进展,但将其应用于固相微萃取领域的研究仍较少;(2)有待进一步明确制备出的衍生多孔碳材料用作固相微萃取涂层表现出优异提取能力的机理;(3)有待进一步深入研究将衍生多孔碳材料用作固相微萃取涂层以实现对不同物理化学性质污染物的广谱高灵敏度分析。文章综述了近3年衍生多孔碳材料在固相微萃取中的应用研究,并展望了未来衍生多孔碳材料在固相微萃取中的研究前景。引用文献共56篇,主要来源于Elsevier。