二维多层PtRu/PtNd纳米薄膜的结构效应及电催化氧化活性

Structural Effects and Electrooxidation Activity of a Two-Dimensional Multilayer PtRu/PtNd Alloy Nanostructure Thin Film

采用离子束多靶溅射技术控制膜层结构制备出二维多层PtRu/PtNd纳米合金薄膜作为微型直接甲醇燃料电池(DMFCs)阳极催化电极材料.应用X射线光电子能谱(XPS)、原子力显微镜(AFM)、X射线衍射(XRD)、掠入射X射线衍射(GIXD)研究了薄膜表面的化学状态、形貌以及薄膜表层、次表层和体相的结构,并用CO-stripping伏安法、循环伏安法(CV)、线性扫描伏安法(LSV)、计时电流法(CA)等电化学方法测试薄膜催化剂的电化学活性比表面积及其对甲醇的电催化氧化.结果表明,多次交替沉积制备的PtRu/PtNd薄膜,由于溅射产生的Pt+、Ru+和Pt+、Nd+之间的相互作用,使薄膜表面的化学状态和膜层结构发生变化,其衍射谱峰呈现异常宽化,Pt与Nd之间产生电子转移,证实了PtRu/PtNd纳米合金薄膜是一种具有特殊膜层结构和电子结构的二维多层PtRu/PtNd纳米合金薄膜,电化学活性比表面积高达115.00m·2g-1,在酸性溶液中电催化氧化甲醇的活性显著提高.

The two-dimensional multilayer PtRu/PtNd alloy nanostructure thin film used for anode electrodes of micro-direct methanol fuel cells （DMFCs） was fabricated by multi-target ion beam sputtering （IBS）. The surface chemical state, structure, surface layer structure, and morphology of the PtRu/PtNd thin-film were characterized by X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, grazing incidence X-ray diffraction （GIXD）, and atomic force microscope （AFM）. Electrochemical properties were examined by CO-stripping voltammetry, cyclic voltammetry （CV）, linear sweep voltammetry （LSV）, and chronoamperometry （CA）. The structure and surface chemical state of the PtRu/PtNd thin film were found to have changed due to a strong interaction between Pt^＋, Ru^＋ and Pt^＋, Nd^＋ during the ion beam alternate sputtering deposition process. Abnormal peak widths in the XRD spectra as well as electron transfer between Pt and Nd have also been observed. The PtRu/PtNd thin-film is shown to have a special multiphase structure and electronic structure. The electrochemical activity-specific surface area of PtRu/PtNd thin-film was 115.00 m^2· g^-1, and therefor PtRu/PtNd thin-film catalysts exhibited higher catalytic activity for methanol electrooxidation in an acidic environment.