制备条件对甲醇电氧化催化剂PtRu/CAs性能的影响

Effect of Preparation Conditions on the Catalytic Performances of PtRu/CAs Catalysts for Methanol Electro-oxidation

利用液相浸渍还原的方法,以炭气凝胶(CAs)为载体制备了担载型Pt-Ru催化剂,其中Pt质量分数为15%,Pt和Ru的原子比为2∶1.研究了金属前驱体于不同介质(CH3COOH,H2O及CH3COONa)中浸渍所制备的催化剂在组成、结构以及对甲醇催化活性方面的区别.催化剂的物化性质通过X射线衍射(XRD)、透射电镜(TEM)以及能谱仪(EDS)表征,并采用循环伏安法测试其电化学性能.结果表明,以CAs为载体,均匀分散于异丙醇与水混合溶液后,先加入CH3COOH使金属前驱体在酸性介质中浸渍,再用NaOH调节pH值至碱性,同时生成CH3COONa作为稳定剂,最后用NaBH4还原所制得的催化剂具有更高的电催化活性,其峰电流密度达到38.24 mA/cm2,远高于其它条件下制备的催化剂.

The impregnation method was applied to prepare the platinum-ruthenium（Pt-Ru） catalysts in which mass fraction of Pt is 15%,and the atomic ratio of Pt and Ru is 2∶1.The properties of the catalysts prepared with varied impregnated mediums（acetic acid,sodium acetate and water） were studied in detail.The X-ray diffractometry（XRD） and transmission electron microscopy（TEM） were used to observe the surface morphology of above Pt-Ru catalysts.The energy dispersive X-ray spectrum（EDS） was used to analyze the composition of the catalysts.The electrochemical performance of the catalysts was examined by cyclic voltammetry with a glassy carbon working electrode in a solution of 1.0 mol/L CH3OH and 0.5 mol/L H2SO4.In all the above catalysts,the catalyst prepared with the metal precursor impregnated in CH3COOH and carbon aerogels as a carrier has the highest electrocatalytic activity.The peak current density gets to 38.24 mA/cm2,which is much higher than the rest of the catalysts prepared under other conditions in this paper.