Electrocatalytic Activity of Ti/TiO_2 Electrodes in H_2SO_4 Solution

Ti/TiO_2 electrodes were prepared with the polymeric precursor method (PPM). The structureand morphology of Ti/TiO_2 electrodes were examined with XRD and ESEM. The voltammetric charge(q~*) of Ti/TiO_2 electrodes as cathode in 0.5 mol/L H_2SO_4 solution was investigated with cyclicvoltammetry. It was found that the electrocatalytic activity of the Ti/TiO_2 electrodes was affected by thestructure and morphology of the Ti/TiO_2 electrodes, in other words, was affected by the calcinationconditions of preparing the electrodes. The value of q_in~* was considerably larger than that of q_out~*, whichmeans that the 'inner' active surface area was much larger than the 'outer' active surface area, and'inner' active surface played a main role in the electrocatalytic activity of the Ti/TiO_2 electrodes.     

Electrochemical characterization of SnO2 electrodes doped with Ru and Pt

Antimony-platinum doped tin dioxide electrodes supported on titanium have been prepared by thermal decomposition. The effect of the progressive replacement of Sb with Ru (x = 0.00; 3.25; 6.50; 13.00 at.%) on their electrochemical response in acid medium has been analysed by cyclic voltammetry. The morphology of the coatings was observed by scanning electron microscopy. Ti/SnO₂-Sb-Pt electrodes without Ru presented a cracked-mud structure, typical of oxide electrodes prepared by thermal decomposition. The introduction of Ru in the oxide layer modified the coating morphology. The roughness increased and passed through a maximum with the increase of Ru content. A relation between the surface morphology, the roughness factor, voltammetric charge and the electrochemical activity has been established. The mechanism and electrocatalytic activity towards the oxygen evolution reaction has been studied from Tafel measurements. The progressive introduction of Ru in the electrodes increased their electrocatalytic activity for the oxygen evolution reaction with a change on the mechanism from non-active to active electrodes. The electrocatalytic activity mainly depends on electronic factors.     

TiO2-SiO2复合氧化物的理化性质及其对柴油加氢精制性能的影响

采用溶胶-凝胶法结合CO₂超临界流体干燥技术制备了不同Ti/Si原子比的TiO₂-SiO₂复合氧化物（TS-n）,考察了Ti/Si原子比、焙烧温度对复合氧化物比表面积、孔结构、酸性及原子结合状态的影响,通过重油催化裂化柴油加氢精制反应考察了以TS-1、TS-4为载体的催化剂脱硫性能的差异.结果表明,TiO2经SiO2复合改性后,热稳定性和晶态稳定性大幅度提高;TiO₂-SiO₂复合氧化物的酸性及原子间的相互作用与Ti/Si原子比有直接的关系;载体的晶态组成及酸性和催化剂的酸性对催化剂的加氢脱硫性能有显著影响,复合氧化物中锐态型TiO₂的存在强化了载体与金属组分之间的相互作用,提高了催化剂的加氢脱硫活性,不同类型的酸性中心对柴油中不同类型的硫化物具有不同的脱除能力,Bronsted 酸中心较多的催化剂对结构简单的硫化物脱除能力强,Lewis酸中心较多的催化剂对结构复杂的硫化物有较好的脱除效果.     

Effects of Precursors for Preparing Intermediate Layer on the Performance of Ti/SnO2+Sb2O3/PbO2 Anode

The Ti/SnO2+Sb2O3/PbO2 anode with SnO2+Sb2O3 intermediate layer obtained by the polymeric precursor method (PPM) and with the conventional route was studied. The morphology and microstructure of SnO2+Sb2O3 intermediate layer derived from different precursors and the top PbO2 active layer were examined by means of ESEM and XRD. The lifetime and electrocatalytic activity of the anode were also assessed by the cyclic voltammetry and accelerated lifetime test in 1.0 mol/L H2SO4 solution. It was found that precursor solvents affected lifetime, microstructure and morphology of the anode, and had little influence on electrocatalysis activity of the electrodes. The accelerated lifetime of Ti/SnO2+Sb2O3/PbO2 anode with intermediate layer prepared by PPM was 29.5 h in 1.0 mol/L H2SO4 solution, which was respectively about four times and twice that of the anode prepared with ethylene glycol and ethanol. After the anode was subjected to thermal corrosion, the lifetime still reached 27 h in contrast to the others.     

Ti/IrO2+MnO2电极在酸性溶液中的电化学活性表面积

采用涂覆热分解法制备不同成分的Ti/IrO₂+MnO₂电极,利用恒电位循环伏安法研究Ti/IrO₂-MnO₂电极在硫酸溶液中的电化学表面行为,并用直线外推法定量地评价电极的电化学活性表面积。结果表明,Ti/(0.7)IrO₂+(0.3)MnO₂的伏安电荷达到最高,为电化学活性表面积最大;随着电位扫描速率增大,伏安电流密度不断增加,而伏安电荷容量逐渐减少,直到维持恒定;所有Ti/IrO₂+MnO₂电极的“内部”电化学活性表面积远大于“外部”电化学活性表面积,约为“外部”电化学活性表面积的2倍,说明电极内部存在丰富的多孔结构,真实表面积巨大,因此Ir⁴⁺/Ir³⁺转化反应多发生于内电化学活性表面区域。     

TiO2纳米管阵列电极电催化降解甲基橙的研究

采用阳极氧化法制备了TiO2纳米管阵列电极.采用场发射扫描电子显微镜（FESEM）和X-射线衍射仪（XRD）表征了电极的表面形貌和晶体结构,应用电化学阻抗谱（EIS）技术研究了不同阳极极化电位下电板的导电性能,应用荧光光谱法研究了电极产生羟基自由基（·OH）的活性,考察了3种支持电解质（Na2SO4、NaNO3和NaCl）对甲基橙（MO）电催化降解效率的影响,通过加入捕获剂探讨了MO分子的降解机理.结果表明,TiO2纳米管阵列电极电极的导电性随阳极极化电位的升高而增强;在电场作用下,TiO2纳米管阵列电极表面生成大量·OH;Na2SO4和NaNO3不参与MO分子的氧化反应,MO的降解符合一级反应动力学模型,而NaCl参与了TiO2纳米管阵列电极电催化降解MO的过程,呈现出复杂的动力学行为;在捕获剂存在的情况下,MO分子仍能发生降解,显示MO分子可在TiO2纳米管阵列电极表面直接氧化.     

Electrochemically created roughened lead plate for electrochemical reduction of aqueous CO2

Surface-roughened Pb electrodes were prepared through a facile oxidation–reduction cycle. Compared with their smooth surface counterparts, the electrodes exhibited significantly higher activity, selectivity, and energy utilization in the electrocatalytic reduction of CO₂ to HCOOH using water under ambient temperature and pressure. Furthermore, the modified electrodes maintained high activities after operating repeatedly for five batches. The enhanced performance of these electrodes is attributed to the enlarged active surface area and increased number of reactive species associated with the three-dimensional structure of the surface. Both the hydrogenation mechanism and the hydrogencarbonate mechanism were affected during the electrochemical CO₂ reduction.     

MoO3/TiO2纳米复合催化剂的合成及催化脱氢性能

采用溶胶-凝胶法合成MoO3/TiO2、K2O-MoO3/TiO2、V2O5-MoO3/TiO2、Al2O3-MoO3/TiO2、K2O-V2O5-MoO3/TiO2系列纳米催化剂。借助TEM、XRD、IR等技术对催化剂进行了表征,并利用环己烷催化氧化脱氢成环己烯的反应进行活性测试。结果表明,MoO3在载体TiO2呈单层和多层分布,单层分布时发生了Mo与O—Ti的键合作用,同时使TiO2表面水分子发生解离反应,活化时脱去—OH产生Mo6+和Mo—O-活性中心;多层分布时以Mo[FY=,1]O、Mo—O-活性物种为主。脱氢中心和供氧中心之间存在协同作用,K、Al、V均能影响其协同作用。     

前驱体溶剂对锡锑电极性能影响的研究

利用热解法在钛基体上制备了锡锑氧化物电极,研究了前驱体对Ti/SnO2-Sb2O3电极性能的影响,并利用金相显微镜和X-射线衍射分析对电极的形貌和结构进行了表征,通过甲基橙降解实验考查了电极的电催化活性。结果表明,乙醇作为前驱体溶液制备的锡锑电极,表面结构致密,在100 A/dm2电流密度下,强化寿命试验可达213min,超过了其他三种前驱体所制备的电极,电解甲基橙褪色率达到95.48%,表现出了良好的性能。     

A comparative study on IrO2-Ta2O5 coated titanium electrodes prepared with different methods

The electrodes of IrO₂-Ta₂O₅ coated titanium were prepared using conventionally thermal decomposition procedure and polymer sol-gel (Pechini) method, respectively. The microstructure and electrochemical properties of the electrodes were studied with scanning electron microscope (SEM), energy dispersive X-ray (EDX), atomic force microscope (AFM), potentiodynamic polarization, cyclic voltammetry, electrochemical impedance spectroscopy and accelerated life test. As compared with the electrode formed using the traditional method of thermal decomposition, the oxide electrode prepared by Pechini method presents morphology of higher nano-scale roughness and more uniform surface composition with little precipitates. It also has larger electrochemically active surface area, better electrocatalytic activity for oxygen evolution and higher stability.     

有序TiO_2纳米管阵列光催化性能研究进展

高度有序TiO₂纳米管阵列由于具有结构的有序性及尺寸的可控性,已成为近年来光催化材料领域的研究热点之一。本文针对有序TiO₂纳米管阵列特殊的结构形貌特点,阐述了管壁粗糙度、管长、管壁厚度、管径及表面积对其光催化性能的影响。在不同的催化剂载体（透明玻璃基底、无基底、钛丝网基底、非平面钛片基底）生长TiO₂纳米管阵列是有效地提高其光催化性能的途径之一,介绍了这些新型结构的TiO₂纳米管阵列的研究进展。最后总结了现阶段主要掺杂改性TiO₂纳米管阵列的方法及掺杂效果。在此基础上,指出了当前研究中存在的主要问题,并展望今后的研究方向。     

新型钛基体PbO2电极的制备及降解性能研究

采用电沉积法制备钛基体PbO2电极并对其表面形貌进行了表征,所制备的电极具有较高的析氧电位和良好的电催化活性。以制备的钛基PbO2为阳极,抛光钛电极为阴极,分别进行电流密度、反应时间、pH、电解质质量浓度等单因素试验,确定PbO2电极对亚甲基蓝的最优降解条件为:pH=6,电解质质量浓度为5.0 g.L-1,电流密度为5×10-2A.cm-2,该条件下亚甲基蓝1 h的降解率可以达到99%;且电流密度为0.25×10-2A.cm-2时能耗最低。     

Solvothermal fabrication of three-dimensionally sphere-stacking Sb–SnO2 electrode based on TiO2 nanotube arrays

TiO₂-NTs-based Sb–SnO₂ electrode with three-dimensionally sphere-stacking structure was successfully fabricated by the solvothermal method, followed by annealing at 500 °C for 1 h. The physico-chemical properties of electrodes were characterized through scanning electron spectroscopy (SEM), X-ray diffraction (XRD) and electrochemical measurements. SEM result showed that TiO₂-NTs/Sb–SnO₂ electrode has morphology of vertically sphere-stacking coralline. Compared with Ti/Sb–SnO₂, TiO₂-NTs/Sb–SnO₂ electrode has smaller grain size and greater specific surface area which can provide with more active sites. Compared with Ti/Sb–SnO₂ electrode, TiO₂-NTs/Sb–SnO₂ has a higher oxygen evolution potential and stronger phenol oxidation peak, indicating an improved catalytic activity for phenol degradation. The kinetic analysis of electrochemical phenol degradation showed that the first-order kinetics rate constant on TiO₂-NTs/Sb–SnO₂ electrode is 1.33 times as much as that on Ti/Sb–SnO₂, confirming that the sphere-stacking Sb–SnO₂ based on TiO₂ nanotube has a good electrocatalytic activity.     

Effect of preparation procedure of Iro<Subscript>2</Subscript>–Nb<Subscript>2</Subscript>o<Subscript>5</Subscript> anodes on surface and electrocatalytic properties

The influence of the electrode manufacturing procedure on surface and electrocatalytic properties for oxygen and ozone evolution at electrodes of nominal composition Ti/[IrO₂–Nb₂O₅] (45:55 mol%) was investigated. Thermal decomposition at 450 °C (1 h, air stream) was adopted as standard procedure. Metal support pretreatment, solvent mixture, method of applying the precursor mixture and calcination procedure were all investigated. X-ray diffraction, scanning electronic microscopy, voltammetric and differential capacity analysis show the use of HCl 1:1 as solvent and applying the mixture by brush led to fragile rugged/porous oxide coatings. However, for the same conditions, but controlled calcination (heating/cooling rates), the coating becomes more compact. Using isopropanol as solvent results in a more homogeneous coating, presenting the lowest morphology factor. Kinetic investigation shows the rugged/porous coating presents the lowest Tafel slopes and the highest global electrocatalytic activity for OER. The more compact the coating the lower the electrochemically active surface area and the global OER activity. Ozone efficiency depends on the electrochemically active area while support pretreatment strongly influences the lifetime of the electrode. Application of a Pt interlayer between the oxide and Ti base improves the service life.     

Electrochemical oxidation of Rhodamine B with cerium and sodium dodecyl benzene sulfonate co-modified Ti/PbO2 electrodes:Preparation,characterization, optimization,application

Regulation of the electronic structure and interface property becomes a major strategy in the preparation of electro-catalyst. This paper reports the synthesis of cerium (Ce) and sodium dodecyl benzene sulfonate (SDBS) co-modified Ti/PbO2 electrodes (Ti/PbO2-Ce-SDBS). Ce and SDBS could greatly change the elec-tronic structure and interface property of PbO2. Ti/PbO2-Ce-SDBS exhibited excellent electrocatalytic activity and stability in Rhodamine B (RhB) electrocatalytic oxidation reaction. The improved electrocat-alytic activity associates with the synergistic effect of electronic and interface factors. In the electrochem-ical degradation of RhB, the removal efficiencies of RhB and COD are about 0.880 and 0.694 respectively after the electrolysis of 220 min with Ti/PbO2-Ce-4-SDBS-40, which are higher than the contrast Ti/PbO2 electrodes. In the meantime, the accelerated lifetime of Ti/PbO2-Ce-4-SDBS-40 is more than 6.2 times than that of Ti/PbO2.     

Electrochemical analysis and convection-enhanced mass transfer synergistic effect of MnOx/Ti membrane electrode for alcohol oxidation

The different electrocatalytic reactors could be constructed for the electrocatalytic oxidation of 2,2,3,3-tetrafluoro-1-propanol(TFP) with two typical MnO_x/Ti electrodes, i.e.the electrocatalytic membrane reactor(ECMR) with the Ti membrane electrode and the electrocatalytic reactor(ECR) with the traditional Ti plate electrode.For the electro-oxidation of TFP, the conversion with membrane electrode(70.1%) in the ECMR was 3.3 and 1.7 times higher than that of the membrane electrode without permeate flow(40.8%) in the ECMR and the plate electrode(21.5%) in the ECR, respectively.Obviously, the pore structure of membrane and convection-enhanced mass transfer in the ECMR dramatically improved the catalytic activity towards the electro-oxidation of TFP.The specific surface area of porous electrode was 2.22 m~2·g~(-1).The surface area of plate electrode was 2.26 cm~2(1.13 cm~2× 2).In addition, the electrochemical results showed that the mass diffusion coefficient of the MnO_x/Ti membrane electrode(1.80 × 10~(-6) cm~2·s~(-1)) could be increased to 6.87 × 10~(-6) cm~2·s~(-1) at the certain flow rate with pump, confirming the lower resistance of mass transfer due to the convection-enhanced mass transfer during the operation of the ECMR.Hence, the porous structure and convection-enhanced mass transfer would improve the electrochemical property of the membrane electrode and the catalytic performance of the ECMR,which could give guideline for the design and application of the porous electrode and electrochemical reactor.     

Improved performance of iron-chromium flow batteries using SnO2-coated graphite felt electrodes

Polyacrylonitrile-based graphite felt has the properties of high temperature resistance, corrosion resistance, low thermal conductivity, large surface area and excellent electrical conductivity. It has become the preferred material for flow battery electrodes, but its chemical activity is poor. In order to improve the electrochemical activity of graphite felt electrodes, the electrodes were prepared by SnO₂-coated graphite felt. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to analyze the microscopic morphology of SnO₂-coated graphite felt electrodes. Electrochemical impedance spectroscopy, cyclic voltammetry and charge-discharge tests were performed using an electrochemical workstation to investigate the electrocatalytic activity of SnO₂-coated graphite felt electrodes and their cell performance. The results show that the SnO₂ coating on the graphite felt surface forms a convex and concave microstructure, which further increases the specific surface area of the electrode, and at the same time successfully introduces oxygen-containing functional groups to the electrode surface, increasing the electrochemically active spots on the surface. In addition, the presence of oxygen defects in the SnO₂ crystal structure provides more electrochemically active sites and improves the electrochemical performance of the graphite felt electrode. At a current density of 142 mA cm^?2, the charge-discharge capacity of the battery assembled with the SnO₂-coated graphite felt electrode was significantly improved; when the current density was 250 mAcm^?2, the Coulombic efficiency of the electrode (TGF-2) coated with a concentration of 0.1 M could reach 84%.     

钨对VOx/TiO2催化燃烧氯苯的作用

采用等体积浸渍法（VO_x和WO_x的添加采用共浸渍）制备不同钨添加量的VO_x-WO_x/TiO₂（VW/Ti）催化剂。采用XRD和EDS对VW/Ti催化剂样品进行表征，并考察催化剂催化燃烧氯苯的活性。结果表明，钨添加前，VO_x/TiO₂催化剂中TiO₂以锐钛矿相和金红石相共存，锐钛矿相为主要晶相，同时还存在V₂O₅晶相；添加一定量钨后，催化剂中TiO₂金红石相和V₂O₅晶相消失，W与Ti质量比0.024时，催化剂中活性组分VO_x在载体TiO₂表面分散最均匀，催化活性最高，T₅₀和T₉₀分别为226.72 ℃和298.67 ℃。W与Ti质量比0.12时，出现WO₃晶相，催化活性略降。因此，适量添加钨不仅可以抑制TiO₂由锐钛矿相向金红石相转变，还可以促进活性组分VO_x在载体上的分散，进而改善催化剂催化降解氯苯的活性。     

胶原纤维为模板介孔TiO_2和Pt掺杂TiO_2纤维的制备及光催化降解黑液（英文）

以胶原纤维为模板,Ti（SO4）2为钛源,合成了新型光催化剂—介孔TiO2和Pt掺杂TiO2纤维。通过场发射扫描电镜（FESEM）、比表面积和孔径分析、紫外–可见光谱和分子荧光光谱等检测手段对两种介孔TiO2纤维的结构和物理性能进行了表征。FESEM分析表明,胶原纤维的表面结构能被较好地保留在介孔TiO2和Pt掺杂TiO2纤维中。N2吸附–脱附等温线为IV型,表明TiO2和Pt掺杂TiO2纤维具有介孔结构。基于结构的特点,在可见光和UV-A激发下,介孔TiO2和Pt掺杂TiO2纤维表现出强于商品级纳米TiO2（Degussa P25）的总有机碳（TOC）脱除率。此外,Pt的掺杂能明显改善介孔TiO2的光催化活性。光催化实验表明,Pt掺杂TiO2纤维（1.0g L–1）在可见光照射420 min后,黑液的TOC脱除率为37%;UV-A（360 nm）照射300min后,TOC脱除率为51%。因此,制备的介孔TiO2和Pt掺杂TiO2纤维作为一类性能优异的光催化剂,能用于黑液的光催化降解,并在其他类似的反应条件下具有潜在的应用前景。     

TiO2基固体超强酸及其在光催化空气净化中的应用

介绍了光催化空气净化催化剂的制备、性能、结构等。总结了国内外关于固体超强酸光催化剂的研究．论述了SO4^2-／TiO2超强酸光催化剂的研究结果，包括其制备、结构和性能之间的关系以及在空气净化方面的实际应用。