光电化学反应的催化I.大颗粒金岛对n-TiO2电极上光电化学过程的催化作用

用溅射、光还原及电沉积法在n-TiO2单晶电极表面上形成了大颗粒金岛,测量了这些电极和纯金电极在H2SO4溶液以及含有Fe[3+]/Fe[2+]的酸溶液中的光电化学极化行为。通过分析和比较这些曲线,确定了大颗粒金岛与n-TiO2单晶的接触具有欧姆结性质。并借助于可换盘旋转环盘电极,在含Ce[3+]的酸溶液中测量了裸TiO2电极及载金TiO2电极上Ce[3+]的竞争光电化学氧化。证实了以大岛形式在TiO2电极表面上分布的催化剂只能催化暗反应,而不能催化光电化学反应。     

光电化学反应的催化 Ⅱ.表面覆盖针状铱层对n-TiO_2电极上光电化学过程的催化作用

借助于可换盘旋转环盘电极在含Ce~(3+)酸性溶液中比较了n-TiO_2电极上载多孔铱层前后的竞争光氧化过程.观察到当铱以高度分散的针状多孔透光层在TiO_2电极表面分布时能够催化Ce~(3+)的光电化学氧化,并据此讨论了催化光电化学反应的基本前题.     

光电化学反应的催化III: 溶液中钴离子及用钴修饰的n-TiO2电极的光催化行为

在溶液中加入钴(II)离子能够催化n-TiO2电极上的光电化学析氧反应,增加光电流-电压曲线的充满因子.用钴修饰的n-TiO2电极能提高光电流,并催化溶液中铈(III)的光氧化反应.本文对这两种催化反应的机理进行了讨论.     

光电化学反应的催化 Ⅰ.大颗粒金岛对n-TiO_2电极上光电化学过程的催化作用

用溅射、光还原及电沉积法在n-TiO_2单晶电极表面上形成了大颗粒金岛.测量了这些电极和纯金电极在H_2SO_4溶液以及含有Fe~(3+)/Fe~(2+)的酸溶液中的光电化学极化行为.通过分析和比较这些曲线,确定了大颗粒金岛与n-TiO_2单晶的接触具有欧姆结性质.并借助于可换盘旋转环盘电极,在含Ce~(3+)的酸溶液中测量了裸TiO_2电极及载金的TiO_2电极上Ce~(3+)的竞争光电化学氧化.证实了以大岛形式在TiO_2电极表面上分布的催化剂只能催化暗反应,而不能催化光电化学反应.     

硝酸银-氨-吡啶甲酸体系的阴极过程研究II. 交换电流和表面扩散步骤

本文报道了用不同方法测得的Ag-AgNO3-NH3-吡啶甲酸体系蜩交换电流值. 探讨了产较大差异的原因, 并得出银从上述体系中电积时, 在低过位区的过电位区的速率控制步骤是吸附离了的表面扩散.     

n型碲化镉单晶光电化学电池的研究II:金属离子修饰与光电化学催化

n-CdTe单晶表面用H2PtCl6或RuCl3溶液浸渍,显著提高了电池的效率及稳定性.除选择金属离子种类外,电极预处理及浸渍时间对修饰作用也有很大影响.固体表面分析表明,在PtCl6^2^-溶液中短时间浸渍的电极表面上有大量铂岛,能减少表面缺陷并催化界面反应.在RuCl3溶液中浸渍,将可使Ru^3^+离子吸附于电极表面,有利于光电化学反应.PdCl2溶液浸渍或长时间PtCl6^2^-溶液处理均得到不利的结果.     

卟啉化合物的电催化行为IV.载在石墨上经热处理的四(对甲氧基苯基)卟啉钴对胱氨酸还原的电催化作用

应用循环伏安法及带环的旋转圆盘电极(RRDE)在2mol.dm^-^3HCl溶液中研究了经热处理的四(对甲氧基苯基)卟啉钴(Co-TMPP)对胱氨酸还原反应的电催化作用.在循环伏安曲线上出现明显的氧化还原电流峰,表明Co-TMPP对胱氨酸还原有很好的电催化活性.在Co-TMPP/石墨电极上的还原反应为不可逆的简单电荷传递反应,其控制步骤的电子数为1.在极化电位较正时(-0.35~-0.45V)为电化学控制,在电位较负时(<-0.45V)为电化学及扩散混合控制.根据实验结果计算了动力学参数并初步讨论了反应机理.应用薄层盘环电极及聚四氟己烯粘结膜电极分别测定了胱氨酸还原反应的电流效率.实验结果表明,经热处理的Co-TMPP能提高胱氨酸还原反应的电流效率.     

Catalysis of photoelectrochemical reactions: II. Catalytic behaviors of Ir needles deposited on n-TiO2 electrode

The competitive photo-oxidation of Ce³⁺ on the surface of n-TiO₂ electrode before and after deposition of porous Ir-needles was studied by using rotating ring-disc electrode with interchangeable disc. It was found that highly dispersed porous layer composed of Ir needles could catalyse the photo-oxidation of Ce³⁺. Basic postulates of catalyst of photoelectrochemical reactions were discussed.     

化学修饰电极的研究XVIII,四苯基钴卟啉化学修饰玻碳电极的热处理及其对氧的催化还原

本文研究四苯基钴卟啉化学修饰玻碳电极的热处理,经热处理的这种电极[(PCo/GC)h]具有对氧催化还原的异常高的稳定性和活性.在纯O2饱和的0.05mol.L^-^1H2SO4溶液中经循环伏安(CV)扫描3000次(100mV/s),其催化活性未见明显降低.研究了热处理温度(500-1000℃)对(PCo/GC)h电极电催化性能的影响.用紫外可见光谱对热处理产物的结构进行了分析.用CV法及旋转圆盘电极研究了O2在(PCo/GC)h电极上电催化反应动力学,测定了速率常数.在该电极上O2的还原反应为二电子还原成H2O2的不可逆过程.     

The catalysis of photoelectrochemical reactions: I. The catalytic action of large gold islands on photoelectrochemical reactions at n-TiO2 electrode

Large gold islands were deposited on n-TiO₂ single crystal electrode by sputtering, photo-reduction and electrodeposition. Photoelectrochemical behaviors of Au-coated semiconductor electrode and pure Au electrode were measured in H₂SO₄ solution and acidic solution containing Fe^2+/3+. From the analysis of these polarization curves it was found that the contact between gold particles and semiconductor surface is mainly ohmic in nature. The catalytic behaviors of gold islands on the competitive photo-oxidation of Ce³⁺ and water were studied by using the RRDE with interchangeable disc. It was proved that gold particles in the form of large islands could only catalyse dark (electrochemical) reaction, but not the photo-electrochemical reaction.     

在氯化物熔体中用铁阴极沉积Nd-Fe合金的电极过程

用循环伏安法、卷积伏安法和计时电位法研究了700℃-850℃下,在NaCl-KCl-NdCl3熔体中Nd(III)在铁电极上还原的阴极过程.对恒电位电解的沉积物进行X射线衍射分析.结果表明,Nd(III)在铁电极上还原时,在形成金属间化合物Fe2Nd后才析出纯金属钕,其中形成Fe2Nd这一步是可逆的.在850℃左右电解制取了含85-90wt%Nd的液态Nd-Fe合金.所得合金的物相被鉴定为Fe2Nd和Nd.     

铅锑合金在硫酸溶液中的阳极膜IV.方波电位对阳极膜生长的影响

The effects of sq. wave potential on the growth rate of the anodic films on Pb-7 Sb and Pb-5 Sb-0.2 As in 4.5 mol/dm3 H2SO4 at 30?were studied by a cathodic linear potential sweep method. By applying the sq. wave potential with period of 3600 s, the potentials of the lead alloys were cycled between that corresponding to the charged conditions of a Pb-acid battery (3 different charge potentials were studied: 1.4, 1.3 and 1.2 V vs. Hg/Hg2SO4, resp.) and that to the discharged condition (1.0 V). The anodic films contain grains with many voids among them as observed with SEM. The surface layer of the grain is PbO2, however, the major constituent of the grain is probably PbO.PbSO4. The relation between the quantity of electricity used to form PbO.PbSO4 and the no. of charges is linear for a certain no. of charge-discharge cycles. The conductance of the film is mainly due to the high conductivity of the PbO2 boundary layers of the grains, especially when the grains are in close contact with one another under pressure.