Advance in electrochemical methods for remediation of organic pollutants in water

介绍利用直接电解、间接电解和电化学吸附等方法去除水中有机污染物的研究现状 ,并指出今后的工作方向。The recent progresses of the electrochemical techniques,such as direct electrolysis,indirect electrolysis and electroadsorption,for remediation of organic pollutants in water were reviewed.And the prospective research work was indicated.福建省自然科学基

The effect of additives on electroless copper plating on ceramic surface

研究了亚铁氰化钾和α ,α′ -联吡啶对陶瓷表面化学镀铜沉积速率、阻抗、镀层晶体结构和外观的影响。加入亚铁氰化钾 ,铜沉积速率降低 ,阻抗增大 ,镀层外观得到改善 ,镀层晶体呈无序生长 ;α ,α′ -联吡啶的加入对铜沉积的抑制更明显 ,镀层晶体取向为 (2 ,2 ,0 )。The effect of potassium ferrocyanide and α,α′-dipyridyl on deposition rate, impedance, microstructure and appearance of electroless copper deposits on ceramic surface was studied. Results show that the addition of potassium ferrocyanide reduces the deposition rate, increases impedance of copper deposition, improves appearance of copper deposits, and results in the disordered crystal growth of copper deposits, while the addition of α,α′-dipyridyl restrains copper deposition further more, and transfers the crystal orientation of copper deposits to (2,2,0)

硅表面直接化学镀镍研究

演示了n-Si(100)不经预先活化处理, 可在碱性镀液中直接进行化学镀镍. 考察了镀液pH值和温度对镀层中金属颗粒尺寸的影响, 并运用能量耗散谱(EDS)分析了硅表面上化学镀层的元素组成. 发现温度的提高或镀液pH值的降低会使沉积层中的金属颗粒尺寸增大. 根据半导体电化学原理讨论了镍离子在硅表面还原的可能机理, 化学镀镍晶种的形成主要归因于在碱性溶液中Si表面上水分子捕获半导体电子而产生原子氢

Kinetic analysis of an enzyme-containing polymer modified electrode

A theoretical model for enzyme-entrapped conducting polymer modified electrodes is proposed and appropriate expressions are derived for the steady-state current response of the enzyme electrode. More attention has been paid to the role of conducting polymer in electron transfer and the effect of mass transport. On the basis of kinetic analysis, the performance and optimum design of the second and third generation enzyme electrodes are discussed

Electrolessly plated Ni-Zn(Fe)-P alloy and its corrosion resistance properties

The autocatalytic deposition of Ni-Zn(Fe)-P alloys has been carried out on substrate of carbon steel from a bath containing nickel sulfate. zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effects of pH and the molar ratio of NiSO4/ZnSO4 on the deposition rate and the composition of deposits have been studied. It was found that the presence of zinc sulfate in the bath has an inhibitory effect on the alloy deposition. The structure and the surface morphology of Ni-Zn(Fe)-P coatings were characterized with XRD and SEM, respectively. The alloys plated under the experimental conditions consisted of an amorphous phase coexisting with a crystalline cubic Ni phase (poly-crystalline). The surface morphology of the coating is dependent on the deposition parameters. The corrosion resistance of the Ni-Zn(Fe)-P deposits was examined via mass loss tests and anodic polarization measurements, respectively. The results show that the surface morphologies of the deposits and the corrosion resistance of the deposits have been improved. The results of mass loss tests almost accord with those of anodic polarization measurements. The corrosion mechanisms of Ni-Zn(Te)-P alloys in NaCl and NaOH solutions were investigated by means of EDX. The deposit immersed in an NaCl or an NaOH solution contains more content of oxygen and less contents of the metals(except Fe) than that placed in air., which shows that the NaCl or NaOH solution can accelerate the oxidation of the deposit

Investigation of Mixed Potential in Electroless Ni-W-P Plating

　测量了化学镀Ni P和Ni W P过程混合电位随时间的变化,并分析其变化规律。指出Emix的正移与pH值随时间而降低有关,而且pH值的降低会加速化学镀的诱发过程。低碳钢诱发化学镀Ni W P会在混合电位 时间曲线上出现两个电位阶梯,其原因在于低碳钢在给定的镀液体系中稳定电位不够负,不能提供足够的能量使化学镀Ni W P快速发生,只有当表面形成达到一定覆盖度的具有催化活性的Ni原子层后,才能迅速地诱发化学镀过程;而Ni P和Ni W P的稳定电位足够负,可以使化学镀过程快速诱发,故仅有一个电位阶梯。The mixed potentials as a function of time were measured during the process of electroless Ni\|P and Ni\|W\|P plating, and their patterns were also analyzed. It was indicated that the positive shift of Emix was related to the pH value which decreased with time, and that the decrease in pH could accelerate the initiation of electroless plating. Two potential steps were observed on Emix\|t curves when the mild steel was used as the substrate of electroless Ni\|W\|P plating because of its less negative stable potential, which couldn't supply enough energy for rapid electroless deposition of Ni\|W\|P, and none but a layer of catalytic nickel with considerable coverage on mild steel was needed for rapidly initiating the electroless plating. However, since sufficient negative stable potentials, Ni\|P and Ni\|W\|P were able to initiate electroless deposition rapidly, hence only one potential step was found.国家自然科学基金资助项目(20073035

The Electroless Plating Ni-Fe-P Alloy and Its Voltammetric Behavior

在以次亚磷酸钠为还原剂 ,硼酸为缓冲剂和柠檬酸钠为络合剂的碱性介质中 ,研究了镍_铁_磷合金化学沉积条件 (pH值 ,温度及 [Fe2 + ]/([Ni2 + ]+[Fe2 + ])物质的量比 )对沉积速率和镀层组成的影响 ;并由此建立镀液稳定的最佳沉积工艺 .实验表明 ,镀液中硫酸亚铁对沉积镍_铁_磷合金有阻碍作用 (降低了化学沉积速率 ) ,造成镀层中铁含量不高 (小于 2 0 % ) ,使用循环伏安技术研究了镍_铁_磷合金的电沉积机理 .结果发现铁对次亚磷酸钠的氧化不起催化作用 ,提高镀液温度和pH值有增加沉积速率之效Electroless Ni_Fe_P alloy deposition from an alkaline bath, containing sodium hypophosphite as reducer, boric acid as buffer agent and sodium citrate as complexing agent, was investigated. To increase the plating rate and to inprove the bath stability, the deposition parameters were optimized. The effects of process parameters (pH,temperature and mole ratio of [Fe 2+ ]/([Ni 2+ ]+[Fe 2+ ]) on the plating rate and deposit composition were examined and it was found that the presence of ferrous sulfate in the bath has an inhibitory effect on the alloy deposition. As a consequence, the per_centage of iron in the electroless Ni_Fe_P alloys never reaches high values which is lower 20.0%. Using cyclic voltammetry the electrodeposition mechanism of Ni_Fe_P alloys was investigated. It was observed that the presence of ferrous sulfate in the bath decreases the deposition rate and the iron doesn′t catalyst on the oxidation of hypophosphite. However, the increase in temperature or pH leads to improving the deposition rate.作者联系地址：华侨大学材料科学与工程学院,厦门大学化学系,固体表面物理化学国家重点实验室 福建泉州362011 ,福建厦门361005Author's Address: 1.College of materials science and engineering,Huaqiao university,Quanzhou 362011, China, 2.State key laboratory for physical chemistry of solid surface,Department of chernistry, Xiamen university, Xiamen 361005, Chin

Deposition and Characterization of Electroless Nickel-Phosphorus-Boron Coatings From Acidic Bath

联用次亚磷酸钠和硼氢化钠两种还原剂 ,从酸性镀液中沉积出不同硼含量的Ni_P_B镀层 ,并用原子力显微镜、X_射线衍射、透射电镜、动电位扫描等实验技术对其镀态结构及性能进行了表征。实验表明 ,镀液中硼氢化钠含量对沉积速度影响不大 ,但能显著影响镀层的化学组成。硼的共沉积使镍晶格点阵产生扭变 ,导致镀层晶粒增大 ,表面粗糙 ,颗粒分布不均匀 ,并使镀层由非晶态向微晶结构转变 ,且微晶成分随镀层中硼含量的增加而增多。Ni_P_B镀层的硬度随镀层中硼含量的增加而增大 ,热处理能显著提高镀层的硬度 ,且服从沉淀硬化机理。在 3.5wt%NaCl和 40wt%NaOH两种介质中 ,Ni_P_B合金的耐腐蚀能力优于Ni_P合金。镀层中硼含量越高 ,其耐腐蚀能力越强。Acknowledgments The authors gratefully acknowledge Professor B.W.Mao for use of AFM facilities at her laboratory. We would also like to thank J.Tang for assistance with AFM measurements.作者联系地址：固体表面物理化学国家重点实验室!厦门大学化学系,福建厦门361005,固体表面物理化学国家重点实验室!厦门大学化学系,福建厦门361005Author's Address: State Key Lab. for Phys. Chem. of Solid Surfaces, Dept. of Chem., Xiamen Univ., Xiamen 361005, Chin

Mechanistic Study of Oxidation of Hypophosphite on Pt Electrodes by SNIFTIRS

用SNIFTIRS和循环伏安法研究次亚磷酸根离子在多晶铂电极上的电氧化机理 .分析了0 .5mol/LH2 SO4 + 0 .1mol/LNaH2 PO2 溶液中原位红外反射谱图与Pt电极电位的关系 ,发现次亚磷酸根离子在Pt上发生解离吸附 ,其氧化产物是H3 PO4 ,不同于在Ni上的氧化产物H2 PO- 3 ,据此提出了酸性溶液中次亚磷酸根离子在Pt上氧化机理的新看法The oxidation of hypophosphite on a polycrystalline platinum electrode was studied by SNIFTIRS and cyclic voltammetry, the in-situ IR spectra were analyzed as a function of Pt electrode potentials in the solution of 0.5 mol/L H 2SO 4+0.1 mol/L NaH 2PO 2. It was found that the dissociative adsorption of hypophosphite ions occurs on Pt surface, and the oxidation product is H 3PO 4, rather than H 2PO 3 - which was considered to produce on Ni electrodes, thereby a new insight into mechanism of hypophosphite oxidation on Pt in acidic media was provided.作者联系地址：厦门大学化学化工学院,固体表面物理化学国家重点实验室,厦门大学化学化工学院,固体表面物理化学国家重点实验室 福建厦门361005 ,福建厦门361005Author's Address: Dept. of Chem., State Key Lab. for Phys. Chem. of the Solid Surfaces,Xiamen Univ., Xiamen 361005, Chin

Direct electroless nickel plating on silicon surface

Direct electroless nickel plating on n-Si(100) wafers in alkaline solutions was demonstrated without any activation procedure in advance, the effect of pH and temperature of the solutions on size of metal particles in deposits was examined, and also the element contents of deposits were analyzed by energy disperse spectroscopy (EDS). The results indicated that the size of metal particles increases with increasing temperature or decreasing pH. The possible mechanism of nickel deposition on n-Si(100) was discussed in terms of semiconductor electrochemistry, and the formation of nickel seed crystal on Si was mainly attributed to the generation of atomic hydrogen by electron capture of water molecule from the semiconductor in alkaline solutions