【作者】 宋曰海；

【导师】 魏刚；

【作者基本信息】 北京化工大学 ， 材料学， 2007， 博士

【摘要】 电极材料是电化学的基础，现代电化学技术和电化学工业发展的技术先导。钛基形稳阳极的开发促进和实现了氯碱工业的革命，使高性能电极材料的研究成为电化学的前沿课题。本工作针对钛基形稳阳极对其它应用领域催化活性不够高，制备成本尚嫌昂贵等问题，进行钛基形稳阳极的改性研究，不锈钢基不溶性催化阳极研究，具有催化活性的阴极材料的研究，进而研究了所制备的电极材料对难降解有机废水的催化活性及其催化作用机理。采用高温热分解方法制备了Ti／IrO₂-RuO₂-CeO₂阳极，试验结果表明，电极制备的优化条件为：涂装次数10～12次，烘干温度80℃，热氧化气氛为氧气，温度450℃，时间10min。经扫描电镜表征，所制得的电极催化层为多孔的蜂窝状结构，无龟裂。在0.5 mol／L H₂SO₄溶液中，电极的析氧电位为1.3V。电极的催化活性优于形稳阳极，制备工艺的复杂性和制备成本与形稳阳极相当。针对钛基形稳阳极对处理难降解废水催化活性不够高，制备成本尚嫌昂贵等问题，提出不锈钢基不溶性催化电极的构想和设计方法，制备了不锈钢基CeO₂-PbO₂阳极。试验结果表明，由于易发生表面氧化等问题，采用制备钛基不溶性阳极常用的热分解法无法在不锈钢基体上制备催化层，本研究采用电沉积法解决了这一难题，得出了电极制备的优化条件：电流密度5～15mA／cm²，温度60℃。电极催化层结构呈多孔状，粒子结构呈四面体型。试验发现，掺杂CeO₂可明显起到细化晶粒的作用。在0.5 mol／L H₂SO₄溶液中，电极的析氧电位为2.1V。在3 mol／L H₂SO₄溶液，电流密度1A／cm²，温度35℃条件下，电极的使用寿命为1100 h。该阳极对染料废水有良好的催化活性，并具有析氧电位高、使用寿命长、制备成本低等优点，尚存在着阳极脆性较大等不足。采用复合电沉积法制备了不锈钢基CNT（碳纳米管）-PbO₂阳极。电极制备的优化条件为：电流密度5～15 mA／cm²，温度60℃。电极催化层粒子结构呈四面体型，碳纳米管晶粒的加入改变了电极催化层微观形貌，生成大量圆柱状小孔，使得电极的比表面积增加。在0.5mol／L H₂SO₄溶液中，电极的析氧电位为1.8 V。该阳极具有良好的催化活性，较高的析氧电位，制备工艺简单等优点。采用脉冲电沉积法，制备了以不锈钢为基体，以非晶态Ni-W-P为载体，掺杂SiC和稀土元素的阴极材料。当电流密度10 A／dm²、pH值4.5，温度65℃，占空比1：3～5时，频率在300～800 Hz范围内，可得到晶粒细小、周边平滑致密、硬度较高的镀层，800 Hz时效果最好。电极镀层结构致密而多孔，具有高的比表面积，因而与氧气接触面积大，对氧气生成H₂O₂具有良好的催化作用。以不锈钢基CeO₂-PbO₂为阳极，不锈钢片为阴极，设计了电催化反应器。反应器结构采用模块化设计思想，每个单元反应室内的电极和曝气设备可以单独进行安装和调换。电极最佳结构和工作参数为：电极间距8 mm，粒子电极粒径4 mm，粒子填充量60％，槽电压15V。在该参数下，电催化反应器对抗生素难降解废水具有良好的处理效果。采用动电位极化法和伏安曲线法等电化学方法，研究了所制备的不溶性电极对有机物的电催化降解机理及其动力学过程，发现在电催化过程中存在着一个特征电位，该特征电位与羟基自由基的产生密切相关，特征电位出现的位置与有机物浓度无关，电流峰值大小随有机物浓度的升高而增大。随有机物溶液温度的上升，电极上出现的特征电位负移，温度与特征电位呈某种直线关系，符合一级反应方程。在电催化过程中，有机物的降解过程符合一级反应规律。更多还原

【Abstract】 Electrode material is the basis for the electrochemistry, which is technology pilot of industrial development of modern electrochemical techniques. The invention of dimensionally stable anodes (DSA) on titanium is realization of the chlor-alkali industry revolution. The research of high performance electrode has become the forefront of electrochemical topics. The electro-catalytic activity of dimensionally stable anode on titanium is not high enough for other applications, and the preparation cost is expensive. The dimensionally stable anodes for the modification on titanium and insoluble anode on stainless steel and catalytic activity of the cathode material were studied. Then we study the catalytic activity of prepared electrode and catalytic mechanism in refractory organic wastewater treatment.The IrO-RuO-CeO on titanium was prepared by high temperature thermal decomposition. The experimental results show that electrodes was prepared under optimum conditions : drying temperature is 80℃, thermal decomposition temperature is 450℃, brushing times is 10-12, the oxidation time is 10 minutes. The surface of the porous electrode is the honeycomb pattern without signs of cracking. The oxygen electrode potential is 1．3 V in 0．5 M HSO solution. The catalytic performance of electrode is superior to conventional dimensionally stable anode. But the electrode preparation is complex and the cost of electrode preparation is high.The CeO-PbO on stainless steel was prepared by electrodeposition. The experimental results show that the optimum conditions for electrode preparation is that current density is 5～15 mA/cm, temperature is 60℃. The electrode structure is tetrahedral and porous with doped Ceria. The crystals of electrode have been refined and the electro-catalytic performance has been increased with the addition of rare earth element. The oxygen evolution over-potential is 2．1 V in 0．5 M HSO solution. The service life of electrode is 1,100 hours on the condition of 3 M sulfuric acid solution, the current density of 1 A/cm, and the temperature is 35℃. The anode has a higher oxygen evolution potential, long service life, low-cost advantages of preparation, particularly good catalytic activity in dyes wastewater treatment, but anode is brittleness. The CNT(carbon nanotubes)-PbO on stainless steel was prepared by composite electrodeposition. The experimental results show that the optimum conditions for electrode preparations are that current density is 5～15 mA/cm, temperature is 20℃. The electrode structure is tetrahedral and cylindrical holes were made on the electrode surface with adding carbon nanotubes grains and that changes the electrode surface. The oxygen evolution over-potential is 1．8 V in 0．5 M HSO solution. The preparation of the anode with an excellent catalyst activity and higher oxygen evolution potential is simple.A new cathode material for wastewater treatment was studied in this paper. The cathode was prepared by impulse electrodeposition on stainless steel substrate, with amorphous ingredients Ni-W-P as a carrier, doped SiC and the rare earth element. The experimental results show that the optimum conditions for electrode preparation is that current density is 10 A/dm, PH is 4．5, temperature is 65℃, duty ratio is 1:3～5, frequency range is 300～800 Hz. The cathode has high catalytic performance, surface area, effectively improving HO reaction rate on the cathode surface. The cathode has the advantage of high hardness and wear resistance.A catalytic reactor was designed and the CeO-PbO on stainless steel used as anode and stainless steel used as cathode. The results show that each module aeration chamber and the electrodes can be individually installed by modular design. The optimal parameters are that the cell voltage is 15 V, particle electrode size is 4 mm, electrode spacing is 8 mm, filler particles is 60%. The antibiotic refractory wastewater is good treated in the electro-catalytic reactor.The electro-catalytic degradation mechanism of organic matter and dynamics process were studied by electrochemical method, such as potentiodynamic polarization technique and cyclic voltammetry method. There is a characteristic potential in the electro-catalytic process. The characteristics potential has to do with hydroxyl radical and has nothing to do with organic matter concentration. The current peak increased with a rise of concentration of organic matter. The potential of electrode decreased with the increase in wastewater solution temperature. The linear relationship between temperature and potential features accords with the first order reaction principle. The electro-catalytic degradation process of organic matter was a first order reaction.更多还原