钌-钯掺杂Ti/TiO2阳极电催化降解甲基橙研究

以偶氮染料甲基橙为处理对象, 分别考察了Ru, Pd及Ru-Pd掺杂的Ti/TiO2阳极的光、电催化活性, 并与Ti/RuOx-PdO阳极的电催化活性进行了比较; 利用XPS分析了Ru-Pd掺杂的Ti/TiO2阳极表面Ru, Pd及Ti的化学形态. 实验发现, Ru, Pd及Ru-Pd掺杂的Ti/TiO2阳极的光催化活性都有所降低, 而其电催化活性却都有大幅提升, 特别是Ru-Pd掺杂的Ti/TiO2阳极, 其电催化活性明显地优于Ti/RuOx-PdO阳极. XPS分析表明, Ru-Pd掺杂的Ti/TiO2阳极其光、电催化活性的变化可能与该阳极表面Ru, Pd及Ti的化学形态变化有关.     

Behavior of 2',4',5',7'-Tetrabromofluorescein on a Platinum Electrode at Anodic Polarization in Aqueous Solution, Simulating Electrolytic Breakdown of Dioxins

Electrocatalytic systems are effective means for breakdown of pollutants in aqueous solution. 2',4',5',7'-Tetrabromofluorescein (eosin) is a convenient model compound for simulation of electrocatalytic oxidation of dioxins. Adsorption of eosin on platinum at potentials exceeding the oxygen evolution potential was discovered. The adsorbate orientation on platinum is presumably planar. The kinetics of electrocatalytic oxidation of eosin in aqueous solution were studied; the reaction orders, rate constants, half-lives, and activation energy were determined. Eosin is oxidized to mineral products (carbonates, bromates). Schemes of the electrocatalytic oxidation of the substrates were suggested.     

双核钴锰酞菁对SOCl2还原反应的电催化性能

为了确定双核金属酞菁化合物对亚硫酰氯还原反应是否具有比单核金属酞菁更强的电催化性能, 通过循环伏安测试方法, 用酞菁钴和酞菁铁作为对比, 研究了双核钴锰酞菁在1.5 mol·L-1 LiAlCl4/SOCl2电解液中的电催化行为, 并计算出动力学参数, 由此来评估具有平面结构的双核金属酞菁化合物对亚硫酰氯还原的催化活性的影响. 通过比较循环伏安曲线发现, 与单核酞菁钴(II)和酞菁铁(II)相比, 双核钴锰酞菁对SOCl2还原反应具有更好的催化活性, 能提高SOCl2还原反应的交换速率常数和SOCl2在玻碳电极上的扩散系数, 从而提高SOCl2还原电位和电流.通过ER14250型实体电池10 mA放电性能测试验证表明, 与单核酞菁钴和酞菁铁催化剂的电池相比, 双核钴锰酞菁在低温(-30 ℃)下可提高放电中点电压0.3 V, 在常温(25 ℃)下可以提高放电容量约100 mAh, 催化效果比单核酞菁钴和酞菁铁显著.     

Fixation of CO_2 by electrocatalytic reduction to synthesis of dimethyl carbonate in ionic liquid using effective silver-coated nanoporous copper composites

<正>With high surface area,open porosity and high efficiency,a catalyst was prepared and firstly employed in electrocatalytic reduction of CO_2 and electrosynthesis of dimethyl carbonate(DMC).The electrochemical property for electrocatalytic reduction of CO_2 in ionic liquid was studied by cyclic voltammogram(CV).The effects of various reaction variables like temperature,working potential and cathode materials on the electrocatalytic performance were also investigated.80%yield of DMC was obtained under the optimal reaction conditions.     

邻溴苯甲酸电化学脱溴反应的原位红外光谱研究

采用循环伏安法研究了水溶液中邻溴苯甲酸在不同电极上的电化学还原脱溴反应,与Ti和C电极相比,Cu电极对邻溴苯甲酸有较好的电化学还原活性。同时采用电化学原位红外反射光谱对其反应机理进行了系统分析,结果表明：邻溴苯甲酸在Cu电极上的电还原脱溴反应是一个脱溴加氢的过程,邻溴苯甲酸在电极表面首先得到一个电子变成邻溴苯甲酸自由基负离子;然后脱去溴离子得到苯甲酸自由基,该自由基再得到一个电子变成苯甲酸负离子;最后加成氢质子得到最终产物苯甲酸,这一产物已经通过恒电流电解实验得到了进一步的证实。     

碳纳米管/SnO2复合电极的制备及其电催化性能研究

采用液相沉积法制备碳纳米管(CNTs)/SnO₂复合材料, 并制备成电极, 分别与石墨/SnO₂及活性炭/SnO₂复合电极比较, 考察电催化降解有机废水的性能. 由于CNTs高的比表面积及优良的导电性能, 结合SnO₂良好的催化活性, CNTs/SnO₂复合电极电催化降解有机废水性能优越. 研究发现, CNTs的预处理情况、SnO₂负载量以及煅烧温度对复合电极的电催化性能有重要影响. 当功能化CNTs负载40% SnO₂, 煅烧温度600 ℃时, 所得CNTs/SnO₂复合电极电催化降解有机废水的能力是纯CNTs电极的2倍. 最后, 初步探讨了CNTs/SnO₂复合电极电催化降解有机废水的机理.     

Electrocatalytic properties of guanine, adenine, guanosine-5'-monophosphate, and ssDNA by Fe(II) bis(2,2':6',2'-terpyridine), Fe(II) tris(1,10-phenanthroline), and poly-Fe(II) tris(5-amino-1,10-phenanthroline)

The electrocatalytic oxidations of guanine, adenine, guanosine-5'-monophosphate(GMP) and ssDNA were performed in the presence of Fe(II) bis(2,2':6',2'-terpyridine) and Fe(II) tris(1,10-phenanthroline) complexes as homogeneous catalysts by cyclic voltammetric methods. The Fe(II/III) redox couple of these compounds is responsible for their catalytic properties. The electrocatalytic oxidation current of above substrates were developed from the anodic peak currents of Fe(II) bis(2,2':6',2'-terpyridine) and Fe(II) tris(1,10-phenanthroline) complexes at about +0.93 V and 0.97 V, respectively. The electrocatalytic oxidative properties of guanine by Fe(II) bis(2,2':6',2'-terpyridine) complex was measured by amperometry method using the rotating disk electrodes. Electropolymerization of Fe(II) tris(5-amino-1,10-phenanthroline) complex produced thin polymer films on gold and glassy carbon electrodes. The electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry were used to study the in situ growth of the polymer. The poly(FeII(5-NH(2)-1,10-phen)(3)) exhibited a good electrocatalytic oxidation towards guanine and also for the mixture of guanine and adenine too.     

Synthesis of flower-like gold nanoparticles and their electrocatalytic activity towards the oxidation of methanol and the reduction of oxygen

This article describes the synthesis of branched flower-like gold (Au) nanocrystals and their electrocatalytic activity toward the oxidation of methanol and the reduction of oxygen. Gold nanoflowers (GNFs) were obtained by a one-pot synthesis using N-2-hydroxyethylpiperazine-N-2-ethanesulphonic acid (HEPES) as a reducing/stabilizing agent. The GNFs have been characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and electrochemical measurements. The UV-visible spectra show two bands corresponding to the transverse and longitudinal surface plasmon (SP) absorption at 532 and 720 nm, respectively, for the colloidal GNFs. The GNFs were self-assembled on a sol-gel-derived silicate network, which was preassembled on a polycrystalline Au electrode and used for electrocatalytic applications. The GNFs retain their morphology on the silicate network; the UV-visible diffuse reflectance spectra (DRS) of GNFs on the silicate network show longitudinal and transverse bands as in the case of colloidal GNFs. The GNFs show excellent electrocatalytic activity toward the oxidation of methanol and the reduction of oxygen. Oxidation of methanol in alkaline solution was observed at approximately 0.245 V, which is much less positive than that on an unmodified polycrystalline gold electrode. Reduction of oxygen to H2O2 and the further reduction of H2O2 to water in neutral pH were observed at less negative potentials on the GNFs electrode. The electrocatalytic activity of GNFs is significantly higher than that of the spherically shaped citrate-stabilized Au nanoparticles (SGNs).     

铂纳米晶的合成及其甲醇电催化性能

以草酰胺作为保护剂,采用胶体法合成铂纳米晶,考察了不同溶液pH值、前驱体与保护剂反应物配比对铂纳米晶形貌及其甲醇电催化氧化活性的影响. 测试表明,pH = 5、反应物配比1:20合成的铂纳米晶的甲醇电催化氧化活性最佳,其峰电流密度达到1709 μA·cm^-2. 空气中搁置3个月后,其表面形貌变化不大,但甲醇的电催化活性显著降低. 0.05 ~ 1.2 V电位范围循环扫描100周期,其循环伏安曲线明显变化,晶体表面原子排列方式也发生变化,由易毒化(100)面逐渐转化为(110)面,其甲醇电催化活性增加.     

Comparison of electrocatalytic characterization of Ti/Sb-SnO<Subscript>2</Subscript> and Ti/F-PbO<Subscript>2</Subscript> electrodes

Electrocatalytic oxidation is a promising process for degrading toxic and biorefractory organic pollutants in wastewater treatment. Selection of electrode materials is crucial for electrochemical oxidation process. In this study, Ti/F-PbO₂ and Ti/Sb-SnO₂ electrodes were chosen to compare their electrocatalytic characterization, which were prepared by electrodeposition and thermal decomposition method, respectively. The surface morphology and crystal structure of two electrodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The linear polarization curves show that Ti/Sb-SnO₂ electrodes possess higher oxygen evolution overpotential than Ti/F-PbO₂ electrodes. But the stability and corrosion resistance ability of Ti/F-PbO₂ electrode was higher than that of Ti/Sb-SnO₂ electrode. The electrocatalytic activity of Ti/F-PbO₂ and Ti/Sb-SnO₂ electrodes was examined for the electrochemical oxidation of malachite green (MG). The bulk electrolysis shows that the Ti/Sb-SnO₂ electrodes exhibit the higher electrocatalytic activity for the degradation of MG than Ti/F-PbO₂ electrodes, and the degradation process is good fitting for the pseudo-first order reaction. The higher electrocatalytic activity of Ti/Sb-SnO₂ electrodes can be attributed to the higher oxygen evolution overpotential.     

纳米PbO/Ti电极催化还原偏硼酸锂制备硼氢化锂

在乙二醇甲醚溶液中电解铅片,制备了铅醇盐配合物,然后将溶液直接水解、凝胶,再通过提拉法涂抹在钛丝表面,450 ℃煅烧2 h制备纳米PbO/Ti电极。 将PbO/Ti电极在0.2~1.0 mol/L LiOH+0.1~0.5 mol/L LiBO2溶液测试催化还原性能,研究了影响电解还原LiBO2制备硼氢化锂(LiBH4)的主要因素,如LiBO2和LiOH浓度等。 通过X射线粉末衍射和扫描电子显微镜对PbO/Ti电极和LiBH4进行了表征。 实验表明,纳米PbO/Ti电极表面颗粒分散较好,修饰电极催化性能稳定,放电电流较大,产率和电流效率分别达15.6%和25.3%。     

Ni-P-TiO2化学复合镀层电极的乙醇电催化氧化

于Ni-P镀液添加TiO2颗粒,用化学镀法在黄铜基底上制备不同TiO2含量的Ni-P-TiO2复合镀层电极.采用循环伏安法、线性扫描法、计时电流和交流阻抗法测定Ni-P-TiO2/Cu电极的电化学性能.结果表明:常温下Ni-P-TiO2/Cu电极在碱性溶液中对乙醇氧化有很高的电催化活性;Ni-P-TiO2电极上乙醇的电催化氧化活性随镀层TiO2量的不同而异;镀液中TiO2含量为5 g.L-1时,所得电极的电催化乙醇氧化的活性最佳.     

炭载微过氧化物酶-11电极对O2和H2O2还原的电催化性能

氧还原;生物燃料电池;炭载微过氧化物酶-11电极对O2和H2O2还原的电催化性能     

Biopolymer and carbon nanotubes interface prepared by self-assembly for studying the electrochemistry of microperoxidase-11

Stable films of biopolymer chitosan and carbon nanotubes were prepared by a layer-by-layer self-assembly technique. Atomic force microscopy, scanning electron microscopy, cyclic voltammetry, and UV-vis spectroscopy were used to characterize the film assembly. Atomic force microscopy and scanning electron microscopy showed that an even, stable film was formed. The UV-vis spectroscopy and cyclic voltammetry study indicated the uniform growth of the film. The property of the self-assembled multilayer film in promoting protein electron transfer was demonstrated by incorporating microperoxidase-11 in the film. Microperoxidase-11 in the multilayer film could transfer electrons with the electrode indicating that carbon nanotubes could wire the protein to the electrode. The electrocatalytic activity of the microperoxidase-11 containing multilayer film-modified electrode toward H(2)O(2) and O(2) was investigated. The results showed that along with the increase in the assembled layers the electrocatalytic reduction potentials of H(2)O(2) and O(2) shifted positively. The prepared multilayer film of chitosan and carbon nanotubes containing protein was a sensitive interface for electrocatalytic study.     

复合金属氧化物Sn-Sb-Mn/陶瓷粒子电极体系的电催化性能

通过热分解法制备了复合金属氧化物Sn-Sb-Mn/陶瓷粒子电极, 分别采用扫描电子显微镜(SEM)、能量色散X 射线能谱(EDS)、X射线衍射(XRD)和N2吸附-脱附等技术对电极的形貌、晶相组成、比表面积和孔径分布进行了表征. 考察了该三维粒子电极系统的析氧特性, 采用循环伏安法分析了三维系统的电催化性能, 并且进行了电化学催化降解苯酚的试验. 结果表明, 制备的陶瓷粒子电极涂层比表面较大、孔结构发达, 有利于电催化反应; 电催化降解主要发生在电化学析氧区; 粒子电极系统对苯酚降解作用显著, 明显高于二维电极系统, 苯酚的去除率为92.3%, 总有机碳(TOC)的去除率为66.7%. 研究结果表明, 该三维粒子电极系统具有优良的电催化性能.     

RuO_2/TiO_2纳米薄膜的新构建及对CO_2的电催化还原

在旋涂有球状纳米TiO2薄膜的导电玻璃(ITO)基底上采用循环伏安法(CV)电沉积RuO2作为电催化还原CO2的阴极.采用场发射扫描电子显微镜(FE-SEM)表征了RuO2/TiO2纳米薄膜的形貌,并应用近稳态电位扫描法和计时电流法(i～t)研究了薄膜的电催化CO2性能.结果表明所构建的RuO2/TiO2薄膜中纳米粒子大小均匀、排列致密,且较传统热分解法所得催化剂有更好的电催化性能.     

F-和Fe3+掺杂对Ti基PbO2阳极性能的影响

采用热分解-电镀法制备了Ti基PbO2,阳极(Ti/PbO2),F-掺杂PbO2阳极(Ti/F-PbO2),Fe3+掺杂PbO2阳极(TiP/Fe-PbO2)和F-,Fe3+共掺杂PbO2,阳极(Ti/F-Fe-PbO2).采用XRD和EDX测试对电极进行了表征,应用加速电解寿命测试和电催化降解4-氯苯酚(4-CP)污水,考察了F-掺杂,Fe3+掺杂和F-,Fe3+共掺杂对PbO2阳极稳定性及电催化活性的影响.结果表明,Ti/F-PbO2和Ti/FePbO2阳极有相近的电催化降解活性,但与Fe3+掺杂相比,F-掺杂大大提高了PbO2阳极的加速电解寿命.对Ti/F-Fe-PbO2阳极,Fe3+掺杂改善了其导电性能.同时F-掺杂提高了阳极的稳定性能,使其有较长的电解寿命.与Ti/PbO2,Ti/F-PbO2和Ti/Fe-PbO2阳极相比,Ti/F-Fe-PbO2阳极的电催化降解活性显著提高,这不仅与其导电性能的改善有关,更与F-掺杂和Fe3+掺杂对4-CP降解的表面协同作用有关.     

Iodine‐Doped Cobalt Phthalocyanine Supported on Multiwalled Carbon Nanotubes for Electrocatalysis of Oxygen Reduction Reaction

4‐(4,6‐Diaminopyrimidin‐2‐ylthio) phthalocyaninatocobalt(II) (CoPyPc) was iodine doped, and its electrocatalytic properties explored. Physical characterization techniques such as UV‐vis, X‐ray photoelectron, electron paramagnetic resonance and infra‐red spectroscopy were used. Cyclic voltammetry, electrochemical impedance spectroscopy and rotating disk electrode were used for electrochemical characterization of electrodes modified with the prepared phthalocyanine and its nanocomposites. The electrocatalytic effect of a new iodine‐doped cobalt phthalocyanine derivative supported on multiwalled carbon nanotubes was then investigated towards oxygen reduction reaction. The electrocatalytic activity of the iodine‐doped cobalt phthalocyanine was found to be superior in terms of current over the undoped phthalocyanine nanocomposite.     

Keggin型缺位硅钨杂多阴离子的电化学性质及电催化还原H2O2

应用循环伏安、方波伏安和交流阻抗法研究了Keggin型缺位硅钨杂多阴离子SiW11O398-(SiW11)在0.1mol.L-1NaHSO4+Na2SO4溶液中的电化学性质及其对H2O2还原的间接电催化作用.结果表明,SiW11的酸性水溶液在玻碳(GC)电极上显示两对可逆的还原-氧化波,对应的电荷迁移数均为1,且有2个质子参与反应.根据第1对波的还原峰电流与扫描速率平方根关系得到SiW11在溶液中的扩散系数DO为8.92×10-6cm2.s-1.SiW11对H2O2的还原具有明显的电催化活性,催化峰电位随溶液pH的降低而正移,峰电流增大.质子H+在催化反应中起协同促进作用.实验测定该电催化过程的均相准一级反应速率常数为0.30 s-1.SiW11电催化还原H2O2的机理被认为是经过形成所谓"七配位过氧化物"而发生的.     

二氧化钛载Ir催化剂对氨氧化的电催化性能

用同一方法制备了Ir含量相同而载体TiO2-晶体结构不同的TiO2-载Ir（Ir/TiO2）催化剂,研究了TiO2-晶体结构对Ir/TiO2催化剂对氨氧化的电催化性能的影响,发现具有金红石结构的TiO2-载Ir（Ir/TiO2-R）催化剂对氨氧化的电催化性能远好于具有锐钛矿型结构的TiO2-载Ir（Ir/TiO2-A）催化剂。 物理化学和电化学的表征揭示了Ir/TiO2-R催化剂对氨氧化的电催化性能好的可能原因归结于Ir纳米粒子在TiO2-R上的均匀分布。