焙烧温度对TiO_2纳米纤维的组成及其载铂催化剂对甲醇电化学氧化活性的影响

Effects of calcination temperature on component of TiO_2 nanofibers and Pt/TiO_2 nanofiber catalysts for methanol electrooxidation

采用静电纺丝技术及随后的高温焙烧制备了不同晶相组成的TiO_2纳米纤维(TiO_2NFs),再经浸渍还原将Pt纳米颗粒负载于其表面,得到Pt/TiO_2纳米纤维催化剂(PT-x,x为焙烧温度).通过X射线衍射(XRD)、透射电镜(TEM)和X射线能量散射谱(EDS)等测试手段对样品的晶相、微结构和化学组成进行了表征.测试结果表明,随着焙烧温度的升高,TiO_2纳米纤维中金红石相含量相应增大,550℃下焙烧获得的TiO_2纳米纤维中金红石含量为2.67%.所制备的催化剂中,Pt负载量均大约为20%,Pt纳米颗粒均匀地分布于TiO_2纳米纤维表面,其中PT-550所负载的Pt纳米颗粒最小.电化学测试结果表明,PT-550催化剂具有较好的催化甲醇氧化活性、抗CO中毒能力和稳定性.

TiO2 nanofibers with different crystal phases were prepared by electrospinning and calcination at different temperatures. Pt/TiO2 nanofiber electrocatalysts（ PT-x,x was the calcination temperature） were achieved by loading Pt nanoparticles on the surface of TiO2 nanofibers using impregnation reduction method. The crystal phase,the microstructure and the chemical composition were investigated by X-ray diffraction（ XRD）,transmission electron microscope（ TEM） and energy disperse spectroscopy（ EDS）. The test results showthat the rutile content of TiO2 nanofibers increases with the increase of the calcination temperature. The rutile content of TiO2 nanofiber obtained at 550℃ is 2. 67%. The Pt content is about 20% and Pt nanoparticles are uniformly distributed on the surface of TiO2 nanofibers. The size of Pt nanoparticles supported by PT-550 is the smallest among the catalysts. The electrocatalytic results showthat,the PT-550 catalyst has better electrocatalytic oxidation activity,CO poisoning resistance ability and stability.