TiO2/γ-Al2O3与铁屑三维电极光电催化研究

以微孤氧化法制备的钛基TiO2/Ti膜为阳极,以钛片为阴极,TiO2/γ-Al2O3与铁屑粒子组合作粒子电极,以Na2SO4为支持电解质,以亚甲基蓝为处理目标物,结合20W紫外灯和稳压电源组成三维电极光电催化体系,研究三维电极体系对光电催化的影响.实验结果表明:粒子电极5g铁屑和2g三层膜球状TiO2/γ-Al2O3粒子,亚甲基蓝溶液初始浓度为3mg/L,电源电压6V,Na2SO4电解质溶液浓度0.02mol/L,电极间距为4.5cm.三维电极光电催化3h的降解效率比传统二维电极光电催化的降解率提高了25％.     

固定态TiO2薄膜制备及光催化氧化性能研究

以TAi钛合金为原料,在不同的成膜电压及电流密度下,用阳极氧化法在基体表面原位生长TiO2薄膜,应用于光催化氧化及光电催化氧化反应体系降解水中的罗丹明B,采用X射线衍射法和扫描电镜对薄膜的粒径、物相进行了表征,结果表明：当成膜电压为160V,电流密度为160mA／cm^2时,薄膜中二氧化钛晶型以锐钛矿型为主,粒径45～50nm;在光催化氧化水中罗丹明B的实验中,90min去除率达到93．5％,该薄膜表现了很好的光催化活性;同时,外加一定的偏压,在降解的最初60min时,外加偏压0．6V比未加偏压(OV)的薄膜电极罗丹明B的去除率提高了33．4％,表明外加偏压可以提高光催化氧化的效率。     

腐殖酸在掺硼TiO2/Ti催化剂上光电催化反应动力学

为去除饮用水中腐殖酸类天然有机物,采用阳极氧化法制备出掺硼TiO2/Ti催化剂,将该催化剂用于光电催化降解腐殖酸(HA)研究腐殖酸光电催化降解反应动力学,结果表明:影响腐殖酸光电催化降解速率的因素由强到弱顺序为:紫外灯功率、催化剂面积、外加偏压、腐殖酸初始质量浓度.在光电催化氧化体系中,优化的降解条件为:紫外灯功率为125 W,催化剂面积为39.8 cm2,外加偏压为1.3 V,腐殖酸初始质量浓度为5 mg/L.     

氧化性物种在光电催化反应中的产生和利用

光电催化技术结合了光催化氧化技术和电催化氧化技术的优点,具有更高的降解效率.文章详细介绍了光电催化反应中的氧化性物种(以羟基自由基为主)的产生途径和产生规律,分析了氧化性物种的利用方式.以期开发出兼具光催化活性和电催化活性的光电极,并将其用于光电催化降解有机污染物中.     

可见光照射下纳晶TiO_2电极对染料污染物的光电催化降解研究

为揭示TiO2光催化降解染料的反应机理,研究了可见光照射下各种染料污染物在正、负不同偏压下的降解情况.以溶胶-凝胶结合水热法制备的TiO2薄膜为光电极,通过检测反应过程中染料溶液的紫外-可见吸收光谱及总有机碳变化情况,深入探讨了外加电压在光电催化降解染料中的作用.同时,通过电子自旋共振技术检测了染料降解过程中活性自由基的生成情况.实验结果表明,在可见光照射下,外加正偏压时,阳离子染料如罗丹明B和孔雀绿虽也褪色,但矿化率比较低;而负偏压作用时,阳离子型染料在可见光与偏压的共同作用下,以分子中共轭结构的破环为主,产生较高的矿化率.     

可见光照射下纳晶TiO2电极对染料污染物的光电催化降解研究

为揭示TiO2光催化降解染料的反应机理,研究了可见光照射下各种染料污染物在正、负不同偏压下的降解情况.以溶胶-凝胶结合水热法制备的TiO2薄膜为光电极,通过检测反应过程中染料溶液的紫外-可见吸收光谱及总有机碳变化情况,深入探讨了外加电压在光电催化降解染料中的作用.同时,通过电子自旋共振技术检测了染料降解过程中活性自由基的生成情况.实验结果表明,在可见光照射下,外加正偏压时,阳离子染料如罗丹明B和孔雀绿虽也褪色,但矿化率比较低;而负偏压作用时,阳离子型染料在可见光与偏压的共同作用下,以分子中共轭结构的破环为主,产生较高的矿化率.     

悬浮TiO2-Ti电极体系中光电催化降解甲基橙

研究了在不同浓度的NaCl电解质溶液中,悬浮TiO2-钛电极体系的光电催化降解效率。当降解时间达到60min时,单独光催化降解甲基橙的降解率为50．7％;在10V电压下进行光电催化反应,以0．5mol／LNaCl为电解质时,可使甲基橙降解率达到98．9％。光电催化法对甲基橙的降解率明显高于光催化法和电降解法,电降解和光催化降解之间存在着协同效应,且降解效率随着外加电压和NaCl溶液浓度的增大而提高．     

活性炭负载TiO2催化剂的制备及光电催化性能的研究

采用溶胶-凝胶法制备TiO2并负载在活性炭(AC)上,在400～700℃下热处理得到TiO2-AC催化剂.用XRD,SEM和氮气吸附等方法表征不同热处理温度下TiO2催化剂的晶相和形貌,通过对亚甲基蓝溶液的降解来评价催化剂的催化活性.结果表明:TiO2颗粒很好地负载在活性炭的表面,热处理温度为600℃时TiO2-AC催化剂活性最高,处理90min后亚甲基蓝的去除率为94.7%.此催化剂的晶相是锐钛矿型TiO2和金红石型TiO2构成的混晶.外加电场能增强催化剂的催化活性,光催化处理亚甲基蓝的去除率为70.5%,光电催化处理1h后其去除率为86.4%.此外,亚甲基蓝的光电催化降解反应符合表观一级动力学.     

氧化镍与氧化石墨烯复合电极的制备及其光电催化性能

通过水热法、电泳法制备了氧化镍-氧化石墨烯复合电极,利用XRD、SEM等对其进行了晶体结构和形貌表征.将所得电极材料用于降解活性艳蓝染料废水,利用电化学工作站、PL、DRS和废水降解考察了样品的理化性质及光电催化活性.结果表明,电泳时间为15 min时,氧化石墨烯修饰后的电极降解效果最好,降解率高达84.45％,与纯氧...     

蜂窝状二氧化钛纳米管阵列的制备及光催化性能

采用二次阳极氧化法,在钛基体上制得蜂窝状整齐有序的TiO2纳米管阵列,借助FESEM、XRD等进行表面形貌和结构晶型的表征和分析,通过对甲基橙的降解检测TiO2纳米管阵列的光催化活性.结果表明:可以通过改变二次阳极氧化的电压有效控制TiO2纳米管阵列结构的参数,氧化电压为20~50V时,下层TiO2纳米管管径为30~80nm、管壁为12~30nm.TiO2纳米管阵列的光催化活性与其形貌有关,蜂窝状TiO2纳米管阵列的光催化效率明显高于一次阳极氧化制得的TiO2纳米管(1.87倍).     

聚吡咯与十二烷基苯磺酸钠修饰的钯-镍双金属电极的制备与性能表征

采用电沉积法,以钛(Ti)网为基体材料,分别用聚吡咯(PPy)修饰、PPy与十二烷基苯磺酸钠(SDBS)联合修饰,制备了钯-镍(Pd-Ni)双金属催化电极(Pd-Ni/PPy/Ti电极和Pd-Ni(SDBS)/PPy/Ti电极),探讨了SDBS掺杂对电极电化学催化活性的影响.循环伏安(CV)测试表明,在研究范围内,Pd-Ni/PPy/Ti电极的最大氢吸附峰电流值为-93 mA,Pd-Ni(SDBS)/PPy/Ti电极的最大氢吸附峰电流值为-154 mA,后者的电催化性能更优.用扫描电镜(SEM)观察了引入PPy和SDBS后电极表面形态的变化.利用电感耦合等离子体-原子发射光谱(ICP-AES)分析了电极表面Pd、Ni的负载量.X射线衍射(XRD)测试结果表明在2种电极上都形成了钯镍合金.实验表明,制备过程中引入表面活性剂SDBS,使Pd-Ni(SDBS)/PPy/Ti电极上的钯负载量减少,同时电催化性能提高,电化学脱氯潜能大.     

Effect of sulphate-reducing bacteria on the electrochemical impedance spectroscopy characteristics of 1Cr18Ni9Ti

The electrochemical characteristics of 1Cr18Ni9Ti in sulphate-reducing bacteria (SRB) solutions and the biofilm of SRB on the surface of the 1Cr18Ni9Ti electrode were studied by electrochemical, microbiological, and surface analysis methods. Electro- chemical impedance spectroscopy (EIS) of 1Cr18Ni9Ti was measured in the solutions with and without SRB at the culture time of 2, 4, 8 d, respectively. The measurement used two test methods, the nonimmersion electrode method and the immersion electrode method. It was found that the polarization resistance (Rp) of 1Cr18Ni9Ti in the solutions without SRB is the greatest for each test method. When using the nonimmersion electrode method, Rp shifts negatively at first and then positively, and the time constant is only one. Although using the immersion electrode method, the Rp shifts positively at first and then negatively, and the time constant also changes when the biofilm forms. The biofilm observed through SEM is with pores. It was demonstrated that SRB has acceler- ated corrosion action on 1Cr18Ni9Ti. The protection effect of the biofilm on the electrode depends on the compact degree of the film.     

Comparative study of oxidation ability between boron-doped diamond （BDD） and lead oxide （PbO_2） electrodes

The electrochemical oxidation capabilities of two high-performance electrodes,the boron-doped diamond film on Ti(Ti/BDD)and the lead oxide film on Ti(Ti/PbO2),were discussed.Hydroxyl radicals(·HO)generated on the electrode surface were detected by using p-nitrosodimethylaniline(RNO)as the trapping reagent.Electrochemical oxidation measurements,including the chemical oxygen demand (COD)removal and the current efficiency(CE),were carried out via the degradation ofp-nitrophenol(PNP)under the galvanostatic condition.The results indicate that an indirect reaction,which is attributed to free hydroxyl radicals with high activation,conducts on the Ti/BDD electrode,while the absorbed hydroxyl radicals generated at the Ti/PbO2 surface results in low degradation efficiency.Due to quick mineralization which combusts PNP to CO2 and H2O absolutely by the active hydroxyl radical directly,the CE obtained on the Ti/BDD electrode is much higher than that on the Ti/PbO2 electrode,notwithstanding the number of hydroxyl radicals produced on PbO2 is higher than that on the BDD surface.     

Hydrothermal preparation and formation mechanism of titanium dioxide microcrystallites

Hydrothermal preparation experiments of TiO_2 microcrystallites were carried out. The formation of TiO_2 microcrystallites of polymorpbic forms was related to the precursor types and the basicity or acidity of reaction mediums under hydrothermal conditions. Based on the "growth unit" model, the space lattice graphs of growth units responding to different polymorphs were established. The stable energy of growth unit was calculated for different basicity or acidity of reaction mediums. The formation of polymorphic TiO_2 microcrystallites under hydrothermal conditions was discussed based on the experimental results.     

不同基体材料的载钯修饰电极的制备及比较

以玻碳板、钛网和泡沫镍为基体材料,通过电沉积法制备载钯催化电极,对比研究基体材料对电极电催化活性的影响.循环伏安测试表明,Pd/GC电极、Pd/Ti电极和Pd/foam-Ni电极的氢吸附峰值分别为-23.46 mA、-59.57 mA和-60.53 mA.扫描电镜分析表明,基体材料影响钯在电极表面的沉积形态,GC板表面呈菱形块状,Ti网表面呈现针状结构,foam-Ni表面呈绒毛状.多孔foam-Ni及Ti网比表面积较大,Pd沉积后拥有更多的催化位点,增强了电极的电催化性能,增大了电极的脱氯潜能.     

血红蛋白固定在Ti0.865O2纳米片层间的直接电化学和电催化

通过对层状纤铁矿型钛酸锂钾进行剥离,可以制备得到Ti0．865O2纳米片溶胶。将Ti0．865O2纳米片作为载体固定血红蛋白（Hb）,制备得到Hb/Ti0．865O2/纳米片修饰的热解石墨（PG）电极。在Ti0．865O2纳米片层间,Hb能实现与电极的直接电子转移。在pH值为5．6的磷酸盐缓冲溶液中,该修饰电极的循环伏安曲线上显示出一对可逆的氧化还原峰,式电位为-230mV（vs．Ag/AgCl）。该修饰电极对H2O2有良好的电催化响应,线性响应范围为50μM到2．2mM,灵敏度为10μA．mM^-1．cm^-2。     

Influence of substrate metals on the crystal growth of AIN films

AIN films were deposited by reactive radio frequency (RF) sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of A1N thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of A1N films depends on the kinds of substrate metals evidently. The differences of A1N films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the A1N material and substrate metals. The A1N film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality A1N films and high-performance film bulk acoustic resonator (FBAR) may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited A1N material and the Pt/Ti electrode substrate.     

Electrochemical Properties of Poly(ethylene oxide )(PEO) Doped TiO_2-PEO Films Prepared by Sol-gel Dip Coating Technique

PEO modified Ti02 -PEO organic-inorganic hybrid thin films were prepared via, sol-gel dipping process on glass substrate pre-coated with ITO. The preparation parameters were studied. Electrochemical and optical properties of the films were characterized by cyclic voltammetric response and visible transmittance. X-ray diffraction (XRD) was used to determined the crystalline structure of the gel. The results show the sols added with PEO have acceptable stable periods for practical use. The PEO modified optical transitivity of the hybrid films has heavy effects on the crystallization of TiO2 during structural evolution because of the interaction between PEO and Ti02 . PEO-TiO2 films have better electrochemical activity than the TiO2 equivalent behaved as higher Li insertion/extraction current density and cyclic reversibility.     

TiO2/Ti电催化膜电极的制备及其对盐酸四环素废水的处理

为高效降解盐酸四环素(TCH)废水,以氢氧化钠、乙醇和水为溶剂,以平板微孔钛膜为钛源和基膜,采用水热法制备出原位生长二氧化钛纳米线的钛基电催化膜(TiO₂ NWs/Ti膜)。运用扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、X射线衍射(XRD)和电化学测试等手段,对TiO₂ NWs/Ti膜电极的形貌、晶型和电化学性能等进行表征,并以TiO₂ NWs/Ti膜为阳极构建电催化膜反应器(ECMR)处理盐酸四环素废水。结果表明:原位生长的催化剂锐钛矿TiO₂纳米线直径约为40 nm,均匀生长在Ti膜上;负载TiO₂纳米线可以显著提高Ti膜电极的电化学性能和催化活性,在常温常压下,当盐酸四环素废水质量浓度为50 mg/L、停留时间为10 min、电流密度为0.8 mA/cm2、pH值为7.0、Na2SO4质量浓度为15 g/L、溶液体积为100 mL时,盐酸四环素去除率可达99.5%,TOC去除率可以达到70.5%,明显高于Ti膜构建ECMR(40.2%和12.8%),且经过10次重复使用,催化性能基本保持较高水平。