一维CoO_x纳米结构原位负载电催化膜制备及催化氧化性能研究

发布时间：2018-01-12 09:21

  本文关键词：一维CoO_x纳米结构原位负载电催化膜制备及催化氧化性能研究　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 苯甲醇 苯甲酸 电催化氧化 电催化膜反应器 一维钴基金属氧化物

【摘要】：开发绿色高效、高选择性的苯甲酸合成体系是精细化学品生产的重点研究方向。针对工业上制备苯甲酸中腐蚀污染严重、产物难分离、操作复杂等问题。本文以管式微孔钛膜为基膜,采用水热热解法原位负载一维CoOx纳米结构,构筑三维CoOx/Ti电催化膜电极。对膜电极的微观形貌、晶形结构及电化学性能进行表征分析,结构表明一维CoOx纳米线原位负载基体钛膜提高了催化剂与膜之间的相互作用力,大大提高了膜电极的活性面积、降低膜与溶液之间的电子传输阻力。以CoOx/Ti电催化膜电极为阳极,不锈钢网为阴极,构建电催化膜反应器(ECMR)。通过调控膜反应器操作参数和反应条件可控高效催化氧化苯甲醇制备苯甲酸。在最优操作条件下,反应温度为21℃,电流密度为2.6 mA cm-2,停留时间为14 min,pH为13.9时,苯甲醇浓度为10 mmol L-1,电解质NaOH浓度为0.125 mol L-1条件下,苯甲醇的转化率大于99%,苯甲酸的选择性为92%。ESR结果证实,Co基电催化膜电极在低压电场激发下,可以产生高活性的羟基自由基,由此实现钴元素价态由低价态向高价态相互转变及基膜与一维CoOx纳米线相互作用进而实现苯甲醇的氧化,通过电催化氧化反应与膜分离一体化实现可控高效、高选择性制备苯甲酸。此外,对比膜电极形貌效应对电催化性能影响,制备了一维CoOx纳米线、一维CoOx纳米针及零维CoOx纳米颗粒负载基体钛膜,并构建电催化膜反应器用于降解含酚废水。结果表明,在常温常压下,电解质Na2SO4浓度为14.4gL-1,pH值为7.0,苯酚初始浓度为470 mg L-1,电流密度为1.0 mAcm-2,停留时间为14 min。纳米针膜反应器降解苯酚效果最佳,其COD和TOC去除率分别为88.6%及73.8%。
[Abstract]:The development of green, efficient and highly selective benzoic acid synthesis system is the key research direction of fine chemical production. In view of the serious corrosion pollution in the industrial preparation of benzoic acid, it is difficult to separate the products. In this paper, the tubular microporous titanium film was used as the base film, and the in-situ loading of one-dimensional CoOx nanostructures was investigated by hydrothermal method. Three-dimensional CoOx/Ti electrocatalytic membrane electrode was constructed. The microstructure, crystal structure and electrochemical properties of the membrane electrode were characterized and analyzed. The structure shows that the in-situ loading of titanium film on one-dimensional CoOx nanowires increases the interaction force between the catalyst and the membrane, and greatly increases the active area of the membrane electrode. CoOx/Ti electrocatalytic membrane electrode was used as anode and stainless steel mesh as cathode. An electrocatalytic membrane reactor (ECM) was constructed to prepare benzoic acid from benzyl alcohol by controlling the operating parameters and reaction conditions of the membrane reactor. Under the optimum operating conditions, the reaction temperature was 21 鈩，

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