钒液流电池用石墨毡电极的电化学修饰

研究了钒液流电池用石墨毡电极的电化学处理,结果发现,电化学处理能提高电极活性,30mA·cm-2电流密度下,电压效率可达90．96％,电流效率达92％．XPS分析表明,电化学处理后,石墨毡表面的O／C比例由0．085增加至0．15,且主要增加的是COOH官能团,与FT-IR分析结果一致．SEM表明碳纤维表面被刻蚀,BET测试结果表明比表面积有所增加．电极活性的提高归因于碳纤维表面COOH官能团数目的增加及比表面积的增大．     

Ir修饰碳毡对VO2+/VO2+电对电催化性能的影响

用热分解法使Ir包覆到碳毡表面,经过50次循环充放电后Ir的附着良好.稳态极化和循环伏安实验结果表明,Ir修饰后的碳毡电极上V(Ⅳ)/V(V)的电荷转移极化电阻降低,Ir催化剂降低了V-O键打开和形成的活化能,从而降低了电池极化.以Ir修饰碳毡为电池正极、酸和热处理的碳毡为负极组成的全钒氧化还原液流电池,在20 mAcm-2充放电时的电压效率达87.5%.与用未经修饰的碳毡组成的电池相比,电压效率提高6.9%,内阻降低了25%.     

全沉积型铅酸液流电池石墨毡正极的性能

以石墨毡为电极材料,以甲基磺酸和甲基磺酸铅溶液为电解液组成全沉积型铅酸液流电池体系,研究了PbO₂/Pb（Ⅱ）电对在石墨毡电极上的电化学反应动力学特征和电极表面改性处理对PbO₂/Pb（Ⅱ）电对反应动力学行为的影响。结果表明:实验测得的PbO₂/Pb（Ⅱ）电对在石墨毡电极上的平衡电极电位值为1.25 V,与理论值接近,且电极反应在平衡状态下的动力学特性较好;循环伏安曲线的氧化峰与还原峰电位分别为1.54 V和1.238 V,表明石墨毡电极Pb（Ⅱ）与PbO₂之间的还原反应比氧化反应更容易;在浓酸、热、热与酸结合三种表面改性方法中,以浓甲基磺酸处理的石墨毡表面电化学活性最好。     

钒液流电池用碳纸电极改性的研究

采用红外光谱、单点比表面积检测手段研究了碳纸435℃热处理前后的表面结构和比表面积的变化. 并将这类碳纸用作全钒液流氧化还原电池电极材料, 对其电化学性能进行了研究. 结果表明：热处理10h的碳纸表面有-COOH官能团生成, 比表面积显著增大, 其电化学活性增强. 热处理后的碳纸作为电极组装成的电池在电流密度50mA/cm²时有良好的充放电性能, 平均电流和电压效率达到95%和89%.     

负载TiO2活性炭电极材料的制备工艺

采用溶胶-凝胶法对活性炭进行载钛改性,制备TiO2/AC电极材料。通过正交实验考察改性过程中无水乙醇(C2H5OH)、去离子水(H2O)、冰乙酸(CH3COOH)、盐酸(HCl)以及活性炭(AC)这五种成分的最佳加入量。利用比表面积及孔径分析仪(BET)、电化学工作站分别对材料的比表面积和电极比电容进行表征。结果表明,材料组成的最佳加入量为无水乙醇30mL、冰乙酸2mL、盐酸0.3mL、去离子水4.5mL、活性炭2g。各因素对电极的电化学性能影响大小依次为:AC量>CH3COOH量>C2H5OH量>去离子H2O量>HCl量。载钛后活性炭比表面积从680.5m2/g降为523.35m2/g,降低23.1%;比电容从116F/g升到135F/g,升高16.4%。活性炭材料负载TiO2处理后,可以加速电极双电子层的形成,提高电极比电容量。     

活性炭表面改性对双电层电容器电化学性能的影响

通过氢气还原改性和浓硝酸氧化处理对石油焦基活性炭(ACs)进行改性.采用氮气吸附和脱附等温线计算改性ACs的BET比表面积、 DFT孔径分布及孔容,以XPS方法表征改性ACs的表面含氧官能团种类及含量,改性ACs的电化学性能通过直流循环充放电、循环伏安等表征.结果表明:浓硝酸处理后,ACs比表面积和孔容均稍有减少,表面含氧官能团和比电容明显增加,内阻和自放电显著增大;氢气改性后,ACs比表面积和孔容亦稍有减少,孔径分布的变化使比电容明显增加,氧化官能团的减少降低了内阻并减少了自放电.即,氢气改性ACs的电化学性能明显提高,增加了比电容,降低了内阻和自放电.     

SnO2修饰石墨毡电极的制备及其性能表征

采用H₂O₂对石墨毡（GF）进行预处理,然后在其表面电沉积Sn,最后在120℃烘箱氧化24 h制备出SnO₂修饰的石墨毡电极。通过扫描电镜（SEM）对SnO₂修饰前后的石墨毡表面形貌进行表征,采用循环伏安法研究了SnO₂修饰后石墨毡电极的电化学性能。结果表明：SnO₂能够均匀地包覆在石墨毡表面;SnO₂修饰石墨毡后V⁴⁺/V⁵⁺电对的氧化峰的峰电流由0.0538 A增加到0.0708 A,与未处理石墨毡相比增加了31.5%,反应峰出峰持续时间提高,说明SnO₂对V⁴⁺/V⁵⁺电对电极过程具有一定的催化作用。析氧电位由1.382 V增加到了1.517 V,使电极在VOSO₄溶液中的电化学窗口变宽。     

电化学改性PAN基碳纤维表面及其机理探析

表面处理是高性能碳纤维制备的重要环节之一. 采用原子力显微镜(AFM)、扫描电子显微镜（SEM）、X射线光电子能谱(XPS)和X射线衍射(XRD)等表征方法, 研究了改性聚丙烯腈（PAN）基碳纤维的表面状态, 探讨了电化学氧化法对碳纤维表面的改性机理. 研究结果表明, 在电化学的化学刻蚀作用下, 碳纤维表面薄弱外层被去除, 表面原有沟槽加宽加深, 表面粗糙度增大了1倍多;在电化学的化学氧化作用下, 碳纤维表面的活性官能团增多, (O1s+N1s)/C1s提高了9.7%. 并提出了电化学氧化同时改善了碳纤维的表面物理状态和表面化学状态的 “物化双效”机理.     

活性炭表面改性对双电层电容器电化学性能的影响（英文）

通过氢气还原改性和浓硝酸氧化处理对石油焦基活性炭(ACs)进行改性。采用氮气吸附和脱附等温线计算改性ACs的BET比表面积、DFT孔径分布及孔容,以XPS方法表征改性ACs的表面含氧官能团种类及含量,改性ACs的电化学性能通过直流循环充放电、循环伏安等表征。结果表明:浓硝酸处理后,ACs比表面积和孔容均稍有减少,表面含氧官能团和比电容明显增加,内阻和自放电显著增大;氢气改性后,ACs比表面积和孔容亦稍有减少,孔径分布的变化使比电容明显增加,氧化官能团的减少降低了内阻并减少了自放电。即,氢气改性ACs的电化学性能明显提高,增加了比电容,降低了内阻和自放电。     

Ti基IrO2+Ta2O5阳极的电化学特性

测量了Ti基IrO2 Ta2O5混合氧化物涂层的电化学阻抗谱（EIS），研究了Ti基IrO2 Ta2O5混合氧化物涂层阳极在H2SO4溶液中的电化学表面结构以及电化学行为，这种涂层阳极具有多层电化学结构，低频段的阻抗行为对应电极外表面/溶液界面的阻抗特性，高频段对应内表面/溶液界面的电化学特性和电极的物理阻抗。在析氧电位下，由于析出氧气的冲击，电极表面的总反应面积增大，而且析出的氧气对电极表面的改性受表面涂层的组织形态影响很大，由于晶粒的最细化，这种改性作用在IrO2含量为70%时最为明显，制备温度的升高使氧化物电极的多孔结构变得不明显，致密度上升以及活性表面积下降。     

Titanium Nitride Nanorods Array-Decorated Graphite Felt as Highly Efficient Negative Electrode for Iron–Chromium Redox Flow Battery

Iron-chromium redox flow batteries have attracted widespread attention because of their low cost. However, the performance of these batteries is still lower than that of vanadium redox flow batteries due to the poor electrochemical activity of Cr³⁺/Cr²⁺ redox couples on graphite felt electrodes. Herein, binder-free TiN nanorods array—decorated 3D graphite felt composite electrode—is demonstrated. The dendrite-like TiN nanorods array increases the specific surface area of the electrode. The nitrogen and oxygen elements on the surface provide more adsorption sites and electrochemically active sites for Cr³⁺/Cr²⁺. The contact resistance of the composite electrode is effectively reduced and its homogeneity and stability are improved by avoiding the use of a binder and mixing process. A battery prepared using the TiN nanorods array-decorated 3D graphite felt electrode has enabled the maximum power density to be 427 mW·cm^-2, which is 74.0% higher than a battery assembled with TiN nanoparticles bonded to graphite felt. At a current density of 80 mA·cm^-2, the TiN nanorods battery exhibits the highest coulombic efficiency of 93.0%, voltage efficiency of 90.4%, and energy efficiency of 84.1%. Moreover, the battery efficiency and composite electrode structure remains stable during a redox flow battery cycle test.     

Construction and performance evaluation of mediator-less microbial fuel cell using carbon nanotubes as an anode material

A microbial fuel cell (MFC) is a device that converts chemical energy to electrical energy using the catalytic reaction of microorganisms. We investigated the performance of mediator-less MFC with carbon nanotubes (CNTs)/graphite felt composite electrodes. The addition of CNTs to a graphite felt electrode increases the specific surface area of the electrode and enhances the charge transfer capability so as to cause considerable improvement of the electrochemical activity for the anode reaction in a MFC. The performance of the MFC using CNTs/graphite felt electrode has been compared against a plain graphite felt electrode based MFC. A CNTs/graphite felt electrode showed as high as 15% increase in the power density (252 mW/m2) compared to graphite felt electrode (214 mW/m2). The CNTs/graphite felt anode therefore offers good prospects for application in MFCs.     

全钒液流电池用碳纳米管-石墨复合电极的研究

将石墨(GP)和多壁碳纳米管(MWNT)按不同比例压片制成电极,用于全钒氧化还原液流电池电极材料,通过循环伏安、交流阻抗、充放电测试、SEM手段对MWNT-GP复合电极进行表征和分析.研究结果表明,MWNT含量为15wt%的MWNT-GP复合电极性能最佳,对组装成的静态电池在电流密度20~80mA/cm2进行充放电性能比较,电流效率均在93%以上,电压效率随着电流密度的增加而有所下降.     

Catalytic conversion of 1,2-dichlorobenzene over mesoporous V2O5/TiO2 prepared from spray pyrolysis

Mesoporous V2O5/TiO2 particles were prepared by spray pyrolysis and applied to the catalytic oxidation of 1,2-dichlorobenzene (1,2-DCB). Two different precursors (alkoxide and nanoparticles) for the TiO2 support were used to determine the effects on the texture properties and the catalytic activity of the mesoporous V2O5/TiO2 particles. The 5 wt% V2O5/TiO2 particles had the largest surface area (173 m2/g) and 4.7 nm in average pore size. The catalytic activity of the V2O5/TiO2 particles depended strongly on the loading quantity of vanadium, whereas the P25-derived samples showed no significant change in catalytic activity with weight% of vanadium. The surface area of the V2O5/TiO2 particles prepared using the alkoxide precursor was larger than that of the particles prepared using P25 nanoparticles. The P25-derived V2O5/TiO2 particles, however, showed a higher catalytic activity compared with those alkoxide-derived, which is due to the difference in the vanadium quantity exposed to the pore surface. It was confirmed that the 10 wt% V2O5/TiO2 particles prepared by spray pyrolysis had an excellent activity for the oxidation of 1,2-DCB, particularly at temperatures below 300 degrees C.     

Highly Stable Vanadium Redox‐Flow Battery Assisted by Redox‐Mediated Catalysis

With good operation flexibility and scalability, vanadium redox‐flow batteries (VRBs) stand out from various electrochemical energy storage (EES) technologies. However, traditional electrodes in VRBs, such as carbon and graphite felt with low electrochemical activities, impede the interfacial charge transfer processes and generate considerable overpotential loss, which significantly decrease the energy and voltage efficiencies of VRBs. Herein, by using a facile electrodeposition technique, Prussian blue/carbon felt (PB/CF) composite electrodes with high electrochemical activity for VRBs are successfully fabricated. The PB/CF electrode exhibits excellent electrochemical activity toward VO²⁺/VO₂⁺ redox couple in VRB with an average cell voltage efficiency (VE) of 90% and an energy efficiency (EE) of 88% at 100 mA cm^?2. In addition, due to the uniformly distributed PB particles that are strongly bound to the surface of carbon fibers in CF, VRBs with the PB/CF electrodes show much better long‐term stabilities compared with the pristine CF‐based battery due to the redox‐mediated catalysis. A VRB stack consisting of three single cells (16 cm²) is also constructed to assess the reliability of the redox‐mediated PB/CF electrodes for large‐scale application. The facile technique for the high‐performance electrode with redox‐mediated reaction is expected to shed new light on commercial electrode design for VRBs.     

Ozone reaction with carbon nanostructures. 2: The reaction of ozone with milled graphite and different carbon black grades

Synthetic graphite particles 0.2 microns in diameter react with O3 at room temperature with evolution of CO2. Graphite is less reactive with ozone than carbon blacks having different surface area ranging from 120 to 8 m2/g, but graphite reactivity is comparable to that shown by powdered solid C60 and C70 fullerenes. The kinetic rate constant derived from the ozone consumption k appears in relation with the rate of CO2 evolution suggesting a very simple reaction stoichiometry at the early stages. The reaction between ozone and graphite or carbon blacks essentially involves two stages: the gasification of the surface to CO2 and its functionalization with oxygenated chemical groups, mainly as COOH but also other oxygenated chemical moieties. The pseudofirst order kinetics appears adequate to describe the heterogeneous reaction between ozone and the selected carbon materials. The discussion of the results is focused on the role played by fullerene-like carbon nanostructures, present in graphene sheets to explain the observed gasification rates and surface functionalization.     

Electrochemical treatment of paper mill wastewater using three-dimensional electrodes with Ti/Co/SnO2-Sb2O5 anode

The properties of the interlayer and outer layer of Ti/Co/SnO2-Sb2O5 electrode were studied, and the electrochemical behavior was examined as well. As a result of unsatisfactory treatment using Ti/Co/SnO2-Sb2O5 electrode, electrochemical disposal of paper mill wastewater employing three-dimensional electrodes, combining active carbon granules serving as packed bed particle electrodes, with Ti/Co/SnO2-Sb2O5 anode, was performed. The outcome demonstrates that efficient degradation was achieved. The residual dimensionless chemical oxygen demand (COD) concentration reached 0.137, and color removal 75% applying 167 mA cm(-2) current density at pH 11 and 15 g l(-1) NaCl. The instant current efficiency, energy cost, electrochemical oxidation index (EOI) and kinetic constant of the reaction were calculated. At the same time, the influence of pH and current density on COD abatement and decolorization was also investigated, respectively.