纳米碳化钨的模板法制备及其电化学性能研究

发布时间：2018-03-12 23:33

  本文选题：模板法　切入点：碳化钨　出处：《江西理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：碳化钨具有类铂催化性能和较强的抗中毒能力,但其催化活性远低于铂等贵金属催化剂。为寻找改善碳化钨催化性能的技术方法,本文使用模板法制备纳米级碳化钨前驱体,以乙醇/甲醇混合液为还原剂和碳源,成功制备了纳米级碳化钨和碳化钨/碳管纳米复合材料,并其电催化性能进行了评价。论文主要研究了碳化钨和碳化钨/碳管纳米材料的制备方法及工艺条件。首先从碳纳米管的纯化与分散入手,高温处理和酸洗有利于去除碳纳米管中的杂质,超声分散选用乙二醇为分散剂有利于碳纳米管又快又好的分散。其次,是在碳纳米管纯化与分散的基础上,以碳纳米管为模板制备钨酸/碳纳米管前驱体,优化工艺参数为:温度为100oC,碳纳米管与钨酸钠的摩尔质量比为1:14。最后为还原碳化步骤,该步骤选择的碳源通入温度为600 o C,碳源中乙醇浓度为10%,以0.2 m L/min的速率升至1000 o C保温1小时。采用SEM、XRD、差热以及HRTAM等分析手段对样品进行了表明,结果表明,本工艺可以制备出纯相WC,WC颗粒粒径小于300 nm。在上述实验的基础上以乙二醇还原法制备的WC/Pt和WC/CNTs/Pt催化剂作为甲醇的电催化材料,比较了两种材料电化学性能。实验结果表明,两种催化剂材料均具有与Pt及Pt电极相类似的电催化氧化性能,即甲醇电催化氧化是通过解离吸附产物和反应中间体双途径机理完成。两种催化剂材料均有较好的电催化活性,但在酸性体系下,复合材料对甲醇的电催化活性略高。
[Abstract]:Tungsten carbide has the catalytic activity of platinum-like and anti-poisoning, but its catalytic activity is much lower than that of noble metal catalyst such as platinum. In order to find a technical method to improve the catalytic performance of tungsten carbide, the nanometer tungsten carbide precursor was prepared by template method. Nanocrystalline tungsten carbide and tungsten carbide / carbon tube nanocomposites were successfully prepared using ethanol / methanol mixture as reducing agent and carbon source. The preparation methods and process conditions of tungsten carbide and tungsten carbide / carbon nanotubes were studied. Firstly, the purification and dispersion of carbon nanotubes were introduced. High temperature treatment and acid pickling are helpful to remove impurities in carbon nanotubes (CNTs), and the ultrasonic dispersion with ethylene glycol as dispersant is beneficial to the rapid and good dispersion of CNTs. Secondly, it is based on the purification and dispersion of CNTs. Tungsten acid / carbon nanotube precursor was prepared by using carbon nanotubes as template. The optimized process parameters are as follows: temperature is 100oC, molar ratio of carbon nanotubes to sodium tungstate is 1: 14.The last step is reduction carbonization. The carbon source input temperature is 600o C, the ethanol concentration in the carbon source is 10 鈩，

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