Boosting Capacitive Deionization Performance of Commercial Carbon Fibers Cloth via Structural Regulation Based on Catalytic-Etching Effect

Monolithic carbon electrodes with robust mechanical integrity and porous architecture are highly desired for capacitive deionization but remain challenging.Owing to the excellent mechanical strength and electroconductivity,commercial carbon fibers cloth demonstrates great potential as high-performance electrodes for ions storage.Despite this,its direct application on capacitive deionization is rarely reported in terms of limited pore structure and natural hydrophobicity.Herein,a powerful metal-organic framework-engaged structural regulation strategy is developed to boost the desalination properties of carbon fibers.The obtained porous carbon fibers features hierarchical porous structure and hydrophilic surface providing abundant ions-accessible sites,and continuous graphitized carbon core ensuring rapid electrons transport.The catalytic-etching mechanism involving oxidation of Co and subsequent carbonthermal reduction is proposed and highly relies on annealing temperature and holding time.When directly evaluated as a current collector-free capacitive deionization electrode,the porous carbon fibers demonstrates much superior desalination capability than pristine carbon fibers,and remarkable cyclic stability up to 20 h with negligible degeneration.Particularly,the PCF-1000 showcases the highest areal salt adsorption capacity of 0.037 mg cm^(−2) among carbon microfibers.Moreover,monolithic porous carbon fibers-carbon nanotubes with increased active sites and good structural integrity by in-situ growth of carbon nanotubes are further fabricated to enhance the desalination performance(0.051 mg cm^(−2)).This work demonstrates the great potential of carbon fibers in constructing high-efficient and robust monolithic electrode for capacitive deionization.

Integration of pore structure modulation and B,N co-doping for enhanced capacitance deionization of biomass-derived carbon

Biomass-derived carbon has demonstrated great potentials as advanced electrode for capacitive deionization(CDI),owing to good electroconductivity,easy availability,intrinsic pores/channels.However,conventional simple pyrolysis of biomass always generates inadequate porosity with limited surface area.Moreover,biomass-derived carbon also suffers from poor wettability and single physical adsorption of ions,resulting in limited desalination performance.Herein,pore structure optimization and element co-doping are integrated on banana peels(BP)-derived carbon to construct hierarchically porous and B,N co-doped carbon with large ions-accessible surface area.A unique expansionactivation(EA)strategy is proposed to modulate the porosity and specific surface area of carbon.Furthermore,B,N co-doping could increase the ions-accessible sites with improved hydrophilicity,and promote ions adsorption.Benefitting from the synergistic effect of hierarchical porosity and B,N co-doping,the resultant electrode manifest enhanced CDI performance for NaCl with large desalination capacity(29.5 mg g^(-1)),high salt adsorption rate(6.2 mg g^(-1)min^(-1)),and versatile adsorption ability for other salts.Density functional theory reveals the enhanced deionization mechanism by pore and B,N co-doping.This work proposes a facile EA strategy for pore structure modulation of biomass-derived carbon,and demonstrates great potentials of integrating pore and heteroatoms-doping on constructing high-performance CDI electrode.

High-yield production of non-layered 2D carbon complexes:Thickness manipulation and carbon nanotube branches for enhanced lithium storage properties

Non-layered two-dimensional(2 D)carbon complexes manifest great potential in energy-related applications owing to their exotic electronic structures,large electrochemically active surface,and intriguing synergistic effects.However,reliable method for mass production and thickness manipulation of 2 D carbon complexes remains great challenges.Here,inspired by blowing chewing gum into bubbles,a“tailored gel expanding"strategy is proposed for high-yield synthesis of non-layered 2 D carbon complexes with tailored thickness from~12 nm to~1 lm,by controllable pyrolysis of metal-polymeric gel with adequate crosslinking degree.The key feature for thickness manipulation is introducing NH4 NO3 in sol-gel process,which tailors the expansion behavior of gel precursor during subsequent pyrolysis.Various of 2 D sheets with intimately coupled N,O-doped carbon(NOC)and Ni Co-based(Ni Co,(Ni Co)S_(2),(Ni Co)Se_(2),Ni Co_(2)O_(4),(Ni Co)(PO_(3))_(2))nanocrystals are obtained on a large scale and without any impurities.Moreover,these 2 D products are branched with in-situ grown CNTs on the surface,accelerating electrons transfer and preventing the nanosheets from stacking.As a demonstration,the 2 D(Ni Co)S_(2)/NOC with optimized thickness manifests excellent lithium storage properties in both half and full cells.This method paves a new path for massive and controlled production of non-layered 2 D materials with tailored thickness and robust structure stability for energy-related applications.

原位聚合法制备巯基功能化的聚(3-4乙撑二氧噻吩)/碳纳米管复合物的电催化活性应用

文中采用原位氧化聚合法制备巯基功能化的聚(3,4乙撑二氧噻吩)与多壁碳纳米管复合物(PEDOT-CH2SH/MWCNTs),通过改变碳纳米管在复合物中的含量获得了最佳比例的复合物,并将其作为电活性材料对重金属离子Cd^(2+)和Pb^(2+)的浓度分别进行了单独检测和同时检测。采用扫描电子显微镜、X射线衍射、傅里叶变换红外光谱和X射线光电子能谱等手段对复合物进行结构表征,用电化学差示脉冲伏安法进行电化学测试,系统探讨了结构与电化学性能之间的关系。结果表明,PEDOT-MeSH/15%MWCNTs的复合物表现出较均匀的多孔状形貌,并增强了对重金属离子Cd^(2+)和Pb^(2+)的灵敏度、选择性和检测稳定性。用PEDOT-MeSH/15%MWCNTs复合物单独检测时,Cd^(2+)和Pb^(2+)的线性范围分别为2~40μmol/L和6~40μmol/L,最低检出限(LOD)分别为2μmol/L和6μmol/L。进行同时检测时,Cd^(2+)和Pb^(2+)的线性范围分别为8~40μmol/L和6~40μmol/L,最低检出限(LOD)分别为6μmol/L和2μmol/L,复合材料表现出较好的响应度和较低的检出限。干扰研究表明,PEDOT-MeSH/15%MWCNTs复合电极具有低相互干扰性和高选择性。

BMO BOUNDEDNESS FOR BANACH SPACE VALUED SINGULAR INTEGRALS

In this paper, we consider a class of Banach space valued singular integrals. The Lp boundedness of these operators has already been obtained. We shall discuss their boundedness from BMO to BMO. As applications, we get BMO boundedness for the classic g-function and the Marcinkiewicz integral. Some known results are improved.

Performance and mechanism of carbamazepine removal by FeS-S_(2)O_(8)^(2–)process:experimental investigation and DFT calculations

As persulfate(S_(2)O_(8)^(2-))is being increasingly used as an alternative oxidizing agent,developing lowcost and eco-friendly catalysts for efficient S_(2)O_(8)^(2-)activation is potentially useful for the treatment of wastewater containing refractory organic pollutant.In this study,the degradative features and mechanisms of carbamazepine(CBZ)were systematically investigated in a novel FeS-S_(2)O_(8)^(2-)process under near-neutral conditions.The results exhibited that CBZ can be effectively eliminated by the FeS-S_(2)O_(8)^(2-)process and the optimal conditions were:250 mg/L FeS,0.5 mmol/L S_(2)O_(8)^(2-),and pH=6.0.The existence of Cl^(−)(1 and 50 mmol/L)has little influence on the CBZ elimination,while both HCO_(3)^(−) and HPO_(4)^(2−)(1 and 50 mmol/L)significantly suppressed the CBZ removal in the FeS-S_(2)O_(8)^(2-)process.CBZ could be degraded via a radical mechanism in the FeS-S_(2)O_(8)^(2-)process,the working radical species(i.e.,SO_(4)•−and•OH)were efficiently formed via the promoted decomposition of S_(2)O_(8)^(2-)by the surface Fe2+on the FeS and the dissolved ferrous ions in solution.Based on the identified oxidized products and Fukui index calculations,a possible degradation pathway of CBZ was speculated.More importantly,a two-stage oxidation mechanism of CBZ elimination was speculated in the FeS-S_(2)O_(8)^(2-)process,the activation of S_(2)O_(8)^(2-)by the surface-active Fe(II)of FeS dominated in the initial 5 min,while homogeneous oxidation reactions played more essential parts than others in the following reaction stage(5–60 min).Overall,this study demonstrated that the FeS-S_(2)O_(8)^(2-)process is capable of removing CBZ from water efficiently.

Comparative study of CO_(2) hydrogenation to methanol on cubic bixbyite-type and rhombohedral corundum-type indium oxide

Hydrogenation of CO_(2) to value-added chemicals has attracted much attention all through the world.In2 O_(3) with cubic bixbyite-type(denoted as c-In2O_(3))is well known for its high CO_(2) hydrogenation activity and CH3 OH selectivity at high temperature.However,the other structure of In2O_(3) with rhombohedral corundum-type(denoted as rh-In2O_(3))rarely been investigated as catalyst.Herein,c-In2O_(3) and rh-In2O_(3) were prepared and comparatively studied for CO_(2) hydrogenation.The results indicated that c-In2O_(3) showed higher CO_(2) conversion activity than rh-In2O_(3) due to the impressive reducibility and reactivity.Whereas rh-In2O_(3) had higher CH3 OH selectivity due to weaker CH3 OH and stronger CO adsorption on rhIn2O_(3).Although c-In2O_(3) and rh-In2O_(3) catalysts showed different CO_(2) hydrogenation perfo rmance,in-situ diffuse reflectance infrared Fourier transform spectroscopy showed CO_(2) can be reduced to CO through redox cycling and hydrogenation to CH3 OH through formate path.