Effect of Outer Carbon Layer Thickness of Carbon-covered N-doped Hollow Carbon Nanospheres on Its Electrocatalytic Performance

Hollow nitrogen-doped porous carbon materials covered with different thicknesses of carbon layers were synthesized to assist evaluation of the influence of nitrogen atom on the surrounding carbon atoms.The designed carbon-based materials were synthesized through pyrolysis of surface-attached block copolymer layers on silica nanoparticles with different thicknesses of the second block of grafted polymer chains,followed by removal of silica templates.The experimental results reveal that coverage a carbon layer with proper thickness can improve the oxygen reaction reduction activity of nitrogen-doped carbon materials as evidenced by the positive shift of half-wave potential in linear scanning voltammetry response curves.The conclusions may provide a reference work on understanding the active sites and designing materials with superior electrochemical performance.     

不同碳源对合成含氮竹节状碳纳米管形貌及结构的影响

分别以二乙胺和仲丁胺为碳源和氮源,以Fe/SBA-15分子筛为催化剂,经过973 K高温催化裂解,得到了含氮竹节状碳纳米管（CNX）。比较了两种不同的碳源对所合成的竹节状碳纳米管的内直径、外直径以及竹节长度的影响,并从含氮竹节状碳纳米管的生成机理上解释了产生这种现象的原因。     

高氮含量多孔碳的制备、热处理及氧还原性能

采用快速高温碳化法成功制备了具有海绵结构、氮原子摩尔分数高达7.5%的氮掺杂多孔碳材料（N-PC）,然后对其进行惰性氛围高温脱氮处理,获得氮原子摩尔分数为2.5%、起始电位-44 mV、半峰电位-134 mV、极限电流密度-4.5 mA·cm^-2的样品。分别用场发射扫描电子显微镜、X射线光电子能谱和Raman光谱对N-PC材料进行了表征。采用伏安法测定了材料在O₂饱和0.1 mol/L KOH电解液中的氧还原反应（ORR）性能。结果发现,高吡啶氮、吡咯氮摩尔分数的多孔碳材料不具备优异的氧还原性能,而脱氮后的多孔碳材料因有较多的结构缺陷,暴露出了更多的活性位点,表现出较好的电化学性能。N-PC具有与Pt/C催化剂相近的电催化性能,而且具有比Pt/C催化剂更高的耐甲醇能力和更好的稳定性。因此,N-PC可以作为铂催化剂在ORR领域的一个非常突出的替代选择。     

Boosting Hydrogen Evolution and Oxygen Reduction Performances of Pd/C upon Surface Phosphorization

表面磷化策略提高 Pd/C 的析氢和氧还原性能

朱桐桐， 王海鸽， 李小鹏， 廖耀祖， 朱美芳

（东华大学 材料科学与工程学院 纤维材料改性国家重点实验室，上海 201620）

中文说明：构筑金属异质结构是实现高性能电催化剂的有效途径之一，共轭微孔聚合物（CMP）是一种具有可设计孔隙率的功能新材料。基于此，本文提出利用CMP 客体化学方法来制备具有双功能电催化活性的PdP2@Pd/C 异质结构。该异质结构的形成依赖于由氮基团组成的 CMP前体，它允许结合 Pd 物质并引入磷掺杂剂。原位形成的 Pd 负载CMP 前体在热解过程中可直接转化为氮和磷化物掺杂的多孔碳（NPC），而 P 则扩散到 Pd/C 界面导致Pd颗粒表面磷化。所制备的由 PdP2@Pd/C（Pd 含量 4 wt.%）异质结构组成的 NPC 表现出显著增强的电催化性能，包括具有高析氢活性（58mV @ 10 mA cm^-2）和接近商业化 20 wt.% Pt/Cd电极的氧还原活性以及出色的循环稳定性。该研究指出了CMP作为客体，在构筑异质结构的电催化剂方面展现的巨大潜力。

关键词：共轭微孔聚合物，钯磷异质结构，双功能电催化剂，析氢反应，氧还原反应

     

Preparation of Sialon powder from coal gasification slag

X-ray fluorescence spectrometry(XRF),X-ray powder diffractometry(XRD) and scanning electron microscopy(SEM) were used to characterize the chemical composition,phase constituent and microstructure of the coal gasification slag.Sialon powders were synthesized by carbothermal reduction and nitridation using the coal gasification slag as raw materials.The experimental results showed that glass and amorphous carbon were the main phases,quartz and calcite as minor crystalline phases were also presented in porous coal gasification slag.Main constituents of coal gasification slag were SiO2,Al2O3,CaO and residual carbon.Sialon powder with Ca-α-Sialon as main crystalline phase can be synthesized when coal gasification slag powders were reduced and nitrided at 1500 ℃ for 9 h using nitrogen flow of 500 ml/min.The coal gasification slag is a valuable and economic starting material for preparing Sialon powders.     

High-performance porous carbon for supercapacitors prepared by one-step pyrolysis of PF/gelatin blends

A high-performance porous carbon material for supercapacitor electrodes was prepared by using a polymer blend method. Phenol-formaldehyde resin and gelatin were used as carbon precursor polymer and pore former polymer, respectively. The blends were carbonized at 800 °C in nitrogen. SEM, BET measurement and BJH method reveal that the obtained carbon possesses a mesoporous characteristic, with the average pore size between 3.0 nm and 5.0 nm. The electrochemical properties of supercapacitor using these carbons as electrode material were investigated by cyclic voltammetry and constant current charge-discharge. The results indicate that the composition of blended polymers has a strong effect on the specific capacitance. When the mass ratio of PF to gelatin is kept at 1:1, the largest surface area of 222 m²/g is obtained, and the specific capacitance reaches 161 F/g.     

多孔碳材料的制备及其在锂离子电池中的应用

利用溶剂热法,将前驱体ZIF-8通过高温在氮气保护的气氛下进行碳化,得到高比表面积的多孔碳材料.通过X射线衍射仪分析材料的物相,比表面积分析仪检测材料的比表面积和吸脱附情况,用扫描电镜来观察材料的微观形貌;最后,对多孔碳材料在锂离子电池中的电化学性能进行了测试,0.1C条件下测得的比容量为284.61 mAh/g,且循...     

Dynamic Adsorption of Toluene on Hierarchical Porous Carbons with Varying Pore Structure

Hierarchical porous carbon material (MMC) was successfully fabricated via hard template synthesis method by carbonization of furfury alcohol within the template (MCM-41).The prepared MMC was studied with characterization methods including scanning electron microscopy (SEM),transmission electron microscopy (TEM),nitrogen adsorption-desorption analyses,and infrared spectral analysis (FTIR).To investigate kinetics of toluene adsorption of hierarchical porous carbon materials,the adsorption performances of these carbon samples with varying pore structure (MC-1,MMC,MMHPC) were analyzed via dynamic adsorption.And the Langmuir model and Freundlich equation were employed to correspond with adsorption isotherms to study the adsorption mechanism.The experimental results demonstrate that the Langmuir model is more appropriate to describe the adsorption process.The capacities of toluene adsorption follow the order of MMC MMHPC (micro-meso hierarchical porous carbon) MC-1(microporous carbon).MC-1 has satisfactory absorption performance due to its large pore volume and high ratio of micropores.MMHPC has excellent toluene adsorption performance for proper amounts of surface oxygen containing groups.Long saturation time,interconnected hierarchical pore channels,and large specific surface area make MMC also a promising material for VOCs treatment.These data reveal that the pore channel structure,rational pore distribution,high surface area and reasonable amounts of surface oxygen groups are the main factors contributed to excellent toluene adsorption performance,which proposes theoretical basis for hierarchical porous carbon materials to further engineering application.     

Graphene as a high-capacity anode material for lithium ion batteries

Graphene was produced via a soft chemistry synthetic route for lithium ion battery applications. The sample was characterized by X-ray diffraction, nitrogen adsorption-desorption, field emission scanning electron microscopy and transmission electron microscopy, respectively. The electrochemical performances of graphene as anode material were measured by cyclic voltammetry and galvanostatic charge/discharge cycling. The experimental results showed that the graphene possessed a thin wrinkled paper-like morphology and large specific surface area (342 m²·g^?1). The first reversible specific capacity of the graphene was as high as 905 mA·h·g^?1 at a current density of 100 mA·g^?1. Even at a high current density of 1000 or 2000 mA·g^?1, the graphene maintained good cycling stability, indicating that it is a promising anode material for high-performance lithium ion batteries.     

Experimental studies of N~+ implantation into CVD diamond thin films

The effects of N+ implantation under various conditions on CVD diamond films were analyzed with Raman spectroscopy, four-point probe method, X-ray diffraction (XRD), Rutherford backseattering spectroscopy (RBS), ultraviolet photoluminescence spectroscopy (UV-PL), Fourier transformation infrared absorption spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the N+ implantation doping without any graphitization has been successfully realized when 100 keV N+ ions at a dosage of 2 × 1016 cm-2 were implanted into diamond films at 550℃ . UV-PL spectra indicate that the implanted N+ ions formed an electrically inactive deep-level impurity in diamond films. So the sheet resistance of the sample after N+ implantation changed little. Carbon nitride containing C≡N covalent bond has been successfully synthesized by 100 keV, 1.2×1018 N/cm2 N+ implantation into diamond films. Most of the implanted N+ ions formed C≡N covalent bonds with C atoms. The others were free state nitroge     

Characteristics of activated carbon prepared from Chinese fir sawdust by zinc chloride activation under vacuum condition

The preparation of activated carbon from Chinese fir sawdust by zinc chloride activation under both nitrogen atmosphere and vacuum conditions was carried out in a self-manufactured vacuum pyrolysis reactor. The effects of the system pressure and the activation condition (nitrogen or vacuum) on pore development were investigated. The results show that both high quality activated carbon and high added-value bio-oil can be obtained simultaneously via vacuum chemical activation. The characteristics of the activated carbons produced under vacuum conditions are better than those prepared under nitrogen atmosphere. The performance parameters of the activated carbon obtained under vacuum conditions are as follows: the pore size distribution is mainly microporous, the Brunauer-Emmett-Teller (BET) surface area is 1 070.59 m²/g, the microporous volume is 0.502 4 cm³/g, the average pore size is 2.085 nm, and the iodine adsorption value and the methylene blue adsorption value are 1 142.92 and 131.34 mg/g, respectively. The activated carbon from vacuum chemical activation has developed micropores, and the N₂ adsorption equilibrium constant of the corresponding activated carbon gradually increases with the decrease of reaction system pressure.     

氮掺杂石墨烯凝胶的制备与表征

为了拓展石墨烯凝胶在超级电容器方面的应用,采用氨水、水合肼作为还原剂和掺杂剂,通过与氧化石墨烯的水热反应制备了氮掺杂石墨烯凝胶,并采用X射线光电子能谱,元素分析、扫描电子显微镜对产物的结构与微观形貌进行表征,采用循环伏安法和计时电位法测试其电化学性能. 结果表明,在氧化石墨烯的水热反应体系中引入氮掺杂剂,不仅能得到具有三维多孔结构的有一定力学强度的凝胶,而且经过氮掺杂后石墨烯的电化学性能较纯石墨烯的有明显提高. 当扫描速率为10 mV/s时,氮掺杂石墨烯的比电容为196 F/g;当电流密度为1 A/g时,氮掺杂石墨烯的比电容达到217 F/g,当循环伏安扫描1 000圈后,电容保持率达到80%. 这表明氮掺杂石墨烯凝胶具有优异的电化学性能,在超级电容器方面有很好的应用前景.     

Preparation of bioactive calcium phosphate coating on porous C/C substrate by a novel deposition technique

A novel heat substrate technique, high frequency inductive heat deposition （IHD）, was introduced to coat porous carbon materials, C/C and carbon felt to improve their bioactivity. The morphologies, composition and microstructure of the resulting coatings were examined by scanning electron microscopy （SEM）, energy dispersive spectra （EDS）, X-ray diffractometer （XRD） and Fourier transform infrared spectroscopy （FTIR）. The results show that, the calcium phosphate consisted of non-stoichiometric, CO3-containing and plate- like octacalcium phosphate （Ca8-xH2（PO4）6, OCP） could uniformly cover the entire porous surfaces of carbon materials. Good adhesion of the coating to carbon material substrates was observed.     

氮掺杂石墨烯/聚苯胺复合凝胶的制备与性能

为了拓展石墨烯凝胶在超级电容器方面的应用,采用氨水与水合肼作为掺杂剂和还原剂,通过与氧化石墨烯的水热反应制备了氮掺杂石墨烯凝胶,并进一步运用原位聚合的方法在氮掺杂石墨烯凝胶上负载聚苯胺,得到氮掺杂石墨烯/聚苯胺复合凝胶. 利用X射线衍射、扫描电子显微镜对产物的结构和微观形貌进行表征,采用循环伏安、恒电流充放电等方法测试其电化学性能. 结果表明,氮掺杂石墨烯/聚苯胺复合凝胶与纯氮掺杂石墨烯凝胶相比,电化学性能有显著的提高. 当扫描速率为10 mV/s时,复合凝胶的比电容约为500 F/g;在恒电流充放电实验中,当电流密度增加到10 A/g时,复合凝胶的比电容仍然保持在约400 F/g. 当循环伏安扫描1 000圈后,比电容的保持率达到80%. 这些表明氮掺杂石墨烯/聚苯胺复合凝胶拥有突出的电化学性能,也表明了氮掺杂石墨烯/聚苯胺在超级电容器方面将会有很好的应用前景.     

Preparation of activated carbons from mesophase pitch and their electrochemical properties

The influences of molar ratio of KOH to C and activated temperature on the pore structure and electrochemical property of porous activated carbon from mesophase pitch activated by KOH were investigated. The surface areas and the pore structures of activated carbons were analyzed by nitrogen adsorption, and the electrochemical properties of the activated carbons were studied using two-electrode capacitors in organic electrolyte. The results indicate that the maximum surface area of 3 190 m2/g is obtained at molar ratio of KOH to C of 5:1, the maximum specific capacitance of 122 F/g is attained at molar ratio of KOH to C of 4:1, and 800 ℃ is the proper temperature to obtain the maximum surface area and capacitance.     

热压成型制备玉米芯基生态炭

以来源丰富、价格低廉的玉米芯为原料,通过炭化和活化（水蒸气为活化剂）制备生态炭。为提高生态炭的收率,炭化前采用热压成型的方法对玉米芯原料进行预处理。通过对成型温度、成型压力、成型时间等工艺参数的研究,得出较佳热压成型条件：成型温度为275~300℃,成型压力为5~15 MPa,成型时间为10 min。研究结果表明,成型工艺参数对总炭化收率的影响程度由大到小依次为：成型温度〉成型压力≈成型时间;热压成型使玉米芯的炭化收率由成型前的18.52%（质量分数）提高到成型后的25.58%;热压成型对生态炭的比表面积影响较小,所制生态炭比表面积为982 m2/g,以微孔为主,微孔率高达97.31%。     

Preparation and characterization of novel porous Fe-Si alloys

Porous Fe-Si alloys with different nominal compositions ranging from Fe-10wt% Si to Fe-50wt% Si were fabricated through a reactive synthesis of Fe and Si elemental powder mixtures. The effects of Si contents on the pore structure of porous Fe-Si alloy were investigated in detail. The results showed that the open porosity, gas permeability and maximum pore size of the porous Fe-Si alloys increased with increasing Si contents, indicating that the porosity and pore size can be tailored by changing the Si contents. The pore structure parameter including the open porosity, gas permeability, maximum pore size obeyed the Hagen-Poiseuille formula with the constant G=0.035 m^-1Pa^-1s^-1 for the reactively synthesized porous Fe-Si alloys. The mechanical property of the porous Fe-Si alloys showed applicability in the filtration industries.     

A2/O+MBBR系统的快速启动及反硝化除磷特性

本研究针对A2/O +移动床生物膜反应器 (A2/O + MBBR) 双污泥系统,考察启动过程的污泥特性和反硝化除磷特性,建立系统的快速启动策略。研究结果表明：启动过程21 d完成,污泥结构稳定且具有较好的污泥沉降性和生物活性;SVI值在95 mL/gMLSS以下,反硝化聚磷菌(DNPAOs)占聚磷菌(PAOs)的百分比从接种污泥时的10.87%增加到25.46%。在平均进水C/N为3.44的运行条件下,A2/O + MBBR系统可实现有机物、氮、磷等污染物的同步高效去除,稳定运行阶段出水COD、NH4+-N、TN和PO43--P浓度分别为38.5,1.15,14.2,0.15 mg/L,COD、TN和PO43--P去除率分别为82.23%,74.72%和96.80%。DO、pH和ORP等实时控制参数的联合调控有利于促进系统的快速启动和稳定运行。     

Synthesis and characterization of W-doped TiO2 supported by hybrid carbon nanomaterials of multi-walled carbon nanotubes and C60 fullerene by a hydrothermal method

W-doped TiO2 supported by hybrid carbon nanomaterials of multi-walled carbon nanotubes and C60 fullerene was synthesized by a simple hydrothermal method. The material displayed high visible light photocatalytic activity. X-ray diffraction, field emission transmission electron microscopy, ultra violet/visible light absorption and photoluminescence spectroscopy were used to characterize the material as photocatalyst. Photocatalytic activity on the degradation of Rhodamine B dye in an aqueous solution under ultraviolet light and visible light irradiation was also studied. The experimental results indicated that the photocatalytic activity of the material was much higher than that of pure TiO2 or Degussa P25 TiO2.     

Low temperature synthesis of nano porous 12CaO∙7Al<Subscript>2</Subscript>O<Subscript>3</Subscript> powder by hydrothermal method

Single-phase insulating 12CaO?7Al₂O₃ (C12A7) powder was synthesized using an optimized hydrothermal method. Pure phase of C12A7 was got at a comparatively lower temperature (c.a. 300 °C) than that has been previously reported. The crystallite size of the synthesized C12A7 powder was 7±2 nm. The surface area values calculated for all the samples at a synthesis temperature range of 250-800 °C for 5 h were in the range of about 19-24 m²/g, with pore sizes of 12-20 nm. This low-temperature-based synthetic strategy along with nano porous structures and a high surface area value can facilitate catalyst application.