Ni/AC膜电极-铝合金储氢电池的研究

采用化学还原法制备了以椰壳活性炭(AC)为载体的Ni/AC电催化剂. 将Ni/AC电催化剂制作成膜电极, 与铝合金一起组成了一种全新概念的高效、安全、廉价的Ni/AC膜电极-铝合金储氢电池. 运用SEM和XRD 对Ni/AC电催化剂的形貌和结构进行了分析, 通过稳态极化曲线研究了Ni/AC膜电极在中性电解液中的电催化活性, 将Ni/AC膜电极与铝合金组装成的模拟电池进行了恒流放电实验以研究其产氢量和放电性能. 结果表明, 镍在活性炭上的负载量为50%时, 活性炭上沉积的镍颗粒最小; 采用镍负载量为50%的Ni/AC电催化剂的Ni/AC膜电极的电催化活性最高, 将其作为正极的储氢电池不仅放电性能好, 产氢量也大.     

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。     

PPy/AC电极的理化性能表征及电吸附除盐性能研究

为了提高活性炭电极在电吸附去离子实验中的除盐效果,实验采用化学原位合成法对活性炭进行负载聚吡咯改性,得到聚吡咯改性活性炭(PPy/AC)并制备电极,研究PPy/AC电极在硝酸钾溶液中的电吸附除盐性能。利用SEM、接触角测试仪、CV、EIS和GCD等多种表征手段分析改性前后活性炭电极的理化性质和电化学特性。结果表明,改性之后,活性炭电极的平均接触角从85.7°减小到60.45°,润湿性变好;比电容由89.66 F/g增加到283.5 F/g,提高了68.37%;电极的导电性变好,电阻变低,离子扩散属于半无限扩散过程;经过100次循环伏安测试后,比电容仅降低了20%,电极具有较好的循环稳定性和再生性。     

含Mn中间层提高钛基SnO2电催化电极的稳定性

采用浸渍法和溶胶-凝胶法分别制备了含Mn中间层和SnO_2表面催化层,并结合高温热氧化工艺制备了Ti/SnO_2和Ti/MnOx/SnO_2电催化电极.采用SEM、EDS和XPS等方法对两种电极进行了表征,使用大电流加速寿命实验详细研究了涂层的表面形貌、元素组成和化学态对两种电极稳定性的影响.结果表明:Ti/MnOx/SnO_2电极的稳定性是Ti/SnO_2电极的4.8倍,涂层使电极的稳定性显著提高.致密的涂层和较多的晶格氧能有效减少或阻止阳极的腐蚀,是电极稳定性提高的主要原因.     

以TiO_2/AC为正极催化剂的空气电极的性能优化

以TiCl4一步水蒸气水解法制备负载均匀的粉状TiO2/AC,以其为催化剂制作成空气电极并组装成空气电池,采用稳态极化曲线法测试其电极性能。分别讨论了正极中聚四氟乙烯(PTFE)和乙炔黑的用量、煅烧时间、活性炭的酸处理及来源对正极放电性能的影响。结果表明,当PTFE的用量为5mL、乙炔黑用量为0.8g、煅烧时间为30min、AC经过酸处理且AC比表面积较大时,空气电极的放电性能较好。     

掺锰活性炭的制备及其电化学性能

分别采用催化法和物理法制得含锰氧化物的中孔活性炭(AC-Mn)和普通活性炭(AC),表征了活性炭的孔容、孔径分布、碘值和亚甲兰值等主要结构、性能指标,并对以这两种活性炭为原料制得的电极进行循环伏安、定电流充放电和交流阻抗测定.结果表明:AC-Mn的收率和碘值分别比AC降低了28.9%和12.4%,但业甲兰吸附值提高了19.8%.AC-Mn的中孔率显著提高,其中3.4nm-4.2nm的中孔增长率最大.AC-Mn电极比电容达93.8F/g.比末负载金属Mn的AC电极高近140%,显示出相对较高的能量密度和良好的准电容特性.     

ZrO_2-AC电极材料制备工艺的确定及性能表征

采用浸渍-焙烧法对活性炭(AC)进行载锆改性,选取浸渍浓度、浸渍时间和焙烧温度为影响因子,以比电容为评价指标,通过单因素和正交试验确定ZrO_2-AC电极材料的最佳制备工艺,利用BET、SEM、EDS及FT-IR对载锆前后活性炭材料进行性能表征。结果表明:ZrO_2改性活性炭的最佳工艺参数为浸渍浓度1.5mol/L,浸渍时间16h,焙烧温度500℃;活性炭负载ZrO_2后比电容增加了72.6%,比表面积降低了12.75%;ZrO_2-AC电极材料的表面及孔道出现絮状和颗粒状的ZrO_2,Zr元素的质量分数为16.8%,表面形成Zr—O键的含氧官能团。活性炭负载ZrO_2后加速了电极双电层的形成,提高了电极材料的电化学性能,可作为电吸附除盐的电极材料。     

炭载MnO2复合电极材料的制备与电容性能研究

采用真空浸溃、化学沉淀法制备活性炭(AC)载MnO2复合电极材料(MAC),利用XRD、SEM、EDS、恒流充放电、循环伏安、交流阻抗等方法对所制备的复合材料进行物性表征和电化学电容性能测试.实验结果表明在AC颗粒表面沉积了γ-MnO2颗粒,所得MAC以200mA/g的电流密度充放电,首次放电比电容高达417F/g,循...     

TiO2/活性炭复合体超临界沉淀法制备及其光催化性能

以活性炭为载体、超临界二氧化碳为流体、钛酸丁酯为前驱体,用超临界流体沉积法制备TiO2/活性炭（TiO2/AC）复合体。用X射线衍射（XRD）、扫描电镜（SEM）、比表面积分析（BET）、热重-差热（TG-DTA）对TiO2/AC进行表征。以紫外灯为光源,偶氮类染料亚甲基蓝为标准降解物,考察TiO2/AC复合体的光催化...     

蔗渣活性炭二次活化制备及其吸附CO2性能研究

以蔗渣为原料, 以ZnCl₂为活化剂制备出活性炭AC, 并用KOH对活性炭AC进行二次活化制备活性炭KAC。用热重法测定材料的CO₂吸附脱附性能, 傅里叶红外光谱、氮气物理吸附-脱附和扫描电镜对样品进行表征。结果表明：KAC具有优异的CO₂吸附性能, 在60℃下其对CO₂吸附量可达3.45 mmol/g, 而AC的CO₂吸附量仅有1.79 mmol/g。KAC的CO₂吸附能力明显优于AC。循环吸附脱附的结果表明, 经过5次吸附-脱附, 材料的吸附量无显著变化, 表明材料具有良好的再生性能。傅里叶红外分析结果表明两种活性炭材料的特征峰基本一致, 活性炭表面官能团中羟基和羧基可以使活性炭表面的极性增大。氮气物理吸附-脱附和扫描电镜结果表明材料都具有发达的孔径结构, 但KAC的孔径结构比AC更发达, 因此其对CO₂的吸附能力也更强。     

Electrochemical oxidation of phenol in a parallel plate reactor using ruthenium mixed metal oxide electrode

In this study, electrochemical oxidation of phenol was carried out in a parallel plate reactor using ruthenium mixed metal oxide electrode. The effects of initial pH, temperature, supporting electrolyte concentration, current density, flow rate and initial phenol concentration on the removal efficiency were investigated. Model wastewater prepared with distilled water and phenol, was recirculated to the electrochemical reactor by a peristaltic pump. Sodium sulfate was used as supporting electrolyte. The Microtox bioassay was also used to measure the toxicity of the model wastewater during the study. As a result of the study, removal efficiency of 99.7% and 88.9% were achieved for the initial phenol concentration of 200 mg/L and chemical oxygen demand (COD) of 480 mg/L, respectively. In the same study, specific energy consumption of 1.88 k Wh/g phenol removed and, mass transfer coefficient of 8.62 x 10(-6)m/s were reached at the current density of 15 mA/cm(2). Electrochemical oxygen demand (EOD), which can be defined as the amount of electrochemically formed oxygen used for the oxidation of organic pollutants, was 2.13 g O(2)/g phenol. Electrochemical oxidation of petroleum refinery wastewater was also studied at the optimum experimental conditions obtained. Phenol removal of 94.5% and COD removal of 70.1% were reached at the current density of 20 mA/cm(2) for the petroleum refinery wastewater.     

活性炭纤维电极法处理含酚废水的研究

以活性炭纤维作为阳极,不锈钢板为阴极,采用电化学氧化法对模拟的含酚废水进行了处理.结果表明,该方法可以有效分解除去水中的苯酚,苯酚和COD的去除率均能达到95%以上,其最佳的操作条件为:pH值为3、进水苯酚浓度为500mg/L、电流密度为26mA/cm2、Na2SO4浓度为15g/L.同时,通过对比不同电极材料的降解效果,证明了具高比表面积的活性炭纤维作为电极材料,能充分将其导电、吸附、催化及稳定性能有效地结合起来,实现高效净化,具有良好的应用前景.     

Electrochemical degradation of phenol using electrodes of Ti/RuO(2)-Pt and Ti/IrO(2)-Pt

Electrochemical degradation of phenol was evaluated at two typical anodes, Ti/RuO(2)-Pt and Ti/IrO(2)-Pt, for being a treatment method in toxic aromatic compounds. The influences of current density, dosage of NaCl, initial phenol concentration on electrochemical phenol degradation were investigated. It was found that Ti/RuO(2)-Pt anode had a higher oxygen evolution potential than Ti/IrO(2)-Pt anode, which will increase the current efficiency for electrochemical degradation, and the instantaneous current efficiency (ICE) was relatively higher at the initial time during phenol electrolysis. HOCl formed during electrolysis would play an important role on the oxidation of phenol. For the Ti/RuO(2)-Pt anode, phenol concentration decreased from around 8mg/L to zero after 30min of electrolysis with 0.3g/L NaCl as supporting electrolyte at the current density of 10mA/cm(2). Although phenol could be completely electrochemical degraded at both Ti/RuO(2)-Pt and Ti/IrO(2)-Pt anodes, phenol degradation was slower at the Ti/IrO(2)-Pt anode than at the Ti/RuO(2)-Pt anode due to the fact that passivation was to be found at the Ti/IrO(2)-Pt anode.     

Ketjenblack carbon supported amorphous manganese oxides nanowires as highly efficient electrocatalyst for oxygen reduction reaction in alkaline solutions

A composite air electrode consisting of Ketjenblack carbon (KB) supported amorphous manganese oxide (MnOx) nanowires, synthesized via a polyol method, is highly efficient for the oxygen reduction reaction (ORR) in a Zn-air battery. The low-cost and highly conductive KB in this composite electrode overcomes the limitations due to low electrical conductivity of MnOx while acting as a supporting matrix for the catalyst. The large surface area of the amorphous MnOx nanowires, together with other microscopic features (e.g., high density of surface defects), potentially offers more active sites for oxygen adsorption, thus significantly enhancing ORR activity. In particular, a Zn-air battery based on this composite air electrode exhibits a peak power density of ～190 mW/cm2, which is far superior to those based on a commercial air cathode with Mn3O4 catalysts.     

Oxidation of various reactive dyes with in situ electro-generated active chlorine for textile dyeing industry wastewater treatment

The present investigation revealed that all the reactive dyes were degraded in chlorine mediated electrochemical oxidation. Titanium based dimensionally stable anode (DSA) was used for in situ generation of chlorine in the dye solution. All classes of reactive dyes (100 mg/L) showed a complete color removal at a supporting electrolyte concentration of 1.5 g/L NaCl and 36.1 mA/cm(2) current density. The chemical oxygen demand (COD) and total organic carbon (TOC) removals were from 39.5 to 82.8% and from 11.3 to 44.7%, respectively, for different reactive dyes. It can be concluded in general that the triazine containing higher molecular weight diazo compounds takes more time for complete de-colorization than the mono azo or anthraquinone containing dye compounds. The degradation rate of mixed dye compounds was affected by reaction temperature, current density, NaCl concentration and initial dye concentration. However, the initial pH of the dye solution ranging from 4.3 to 9.4 did not show significant effect on de-colorization. A complete color removal with 73.5% COD and 32.8% TOC removals were obtained for mixed reactive dyes (200 mg/L) at the end of 120 min of electrolysis under the optimum operating conditions of 4 g/L NaCl concentration and 72.2 mA/cm(2) current density.     

Non-passivating polymeric structures in electrochemical conversion of phenol in the presence of NaCl

The formation of non-passivating polymeric structures was investigated during electrochemical conversion of phenol using carbon electrodes and NaCl as electrolyte. The influence of initial phenol concentration, current density and reaction temperature on phenol conversion and polymer morphology was studied by FTIR and STM, while the fate of intermediate compounds was analyzed by GC/MS. Unlike previous work, non-passivating solid polymer was produced at high voltage and current density values in the presence of NaCl. The most orderly polymer formed at 912 mg l(-1) initial phenol concentration, current density 32.9 mA cm(-2), NaCl concentration 120 g l(-1) and temperature 25 degrees C. Higher operational parameters yielded disorderly formed aggregates of the polymer in decreasing surface density on STM images. Along with the polymer, only toxic mono-, di- and tri-chlorophenols were formed as intermediate compounds during the electrochemical conversion, which eventually were polymerized and/or oxidized to final products. FTIR analysis and enlarged STM image implied the repeating phenol units in the polymer structure. The results may lead to appropriate techniques for the removal of phenol from wastewater in the form of a solid polymer.     

膨胀石墨基炭/炭复合电极的制备及含酚废水的降解

以压缩膨胀石墨为基体、蔗糖为炭源、磷酸为活化剂,经碳化、活化压片制得膨胀石墨基炭/炭复合电极(EGC电极)。采用低温液氮吸附法和扫描电镜(SEM)进行表征,研究了蔗糖浓度对电极表面结构和孔道特征的影响规律,并以苯酚为处理目标物,考察了不同的电解条件。结果表明,EGC电极以膨胀石墨为骨架,包覆炭膜,孔径主要分布在0.5～2.5nm之间,蔗糖浓度为50%制备的EGC电极比表面积最高,电化学氧化苯酚效果最优。电解苯酚试验中,降低苯酚初始浓度、增加电流密度和电解质浓度有利于提高苯酚的降解效率。     

Optimization of Bomaplex Red CR-L dye removal from aqueous solution by electrocoagulation using aluminum electrodes

In this paper, Taguchi method was applied to determine the optimum dye removal from aqueous solution by electrocoagulation using aluminum electrodes. An orthogonal array (OA(16)) experimental design that allows to investigate the simultaneous variations of five parameters (initial dye concentration, initial pH of the solution, supporting electrolyte concentration, supporting electrolyte type and current density) having four levels was employed to evaluate the effects of experimental parameters. Performance measure analysis was followed by performing a variance analysis, in order to determine the optimum levels and relative magnitude of the effect of parameters. Because the desired characteristic for response has been maximum decolorization, Taguchi's 'the larger the better' performance formula was used. While the optimum conditions were found to be initial dye concentration of 100 mg/L, initial pH of the solution of 3, supporting electrolyte concentration of 0.0 mM, supporting electrolyte type of CaCl(2) and current density of 0.50 mA/cm(2). Under these optimum conditions, energy consumption is 0.607 kWh/kg dye, when the system evaluated also based on the energy consumptions it can be said that optimum conditions should be modified as follows: supporting electrolyte concentration of 2.5 mM; supporting electrolyte type NaCl, for 100 mg/L initial dye concentration; initial pH of the solution of 3; current density of 0.50 mA/cm(2).     

Preparation and characterization of Ti/SnO(2)-Sb(2)O(3)-Nb(2)O(5)/PbO(2) thin film as electrode material for the degradation of phenol

In this work, a novel electrode of titanium substrate coated with mixed metal oxides of SnO(2), Sb(2)O(3), Nb(2)O(5) and PbO(2) was successfully prepared using thermal decomposition and electrodeposition. The surface morphology and the structure of the prepared thin film were characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD), respectively. Experimental results showed that the structure of the prepared electrode might be described as a Ti/SnO(2)-Sb(2)O(3)-Nb(2)O(5)/PbO(2) thin film and its surface was mainly comprised pyramidal-shape beta-PbO(2) crystals. The modified electrode had higher oxygen evolution potential than that of other PbO(2) modified electrodes. Electrocatalytic oxidation of phenol in aqueous solution was studied to evaluate the potential applications of this electrode in environmental science. The phenol removal efficiency in an artificial wastewater containing 0.50g/L phenol could reach 78.6% at 20 degrees C and pH 7.0 with an applied electricity density of 20mA/cm(2) and treatment time of 120min. When 21.3g/L chloride was added to this wastewater, the removal efficiency could reach to 97.2%.