梯度化Pt基载体膜电极制备及膜界面孔道形态控制研究
发布时间：2019-06-21 07:08
【摘要】：贵金属Pt由于其较高的催化活性、良好的耐腐蚀、抗氧化与稳定性等使得其在各行各业中得到应用,但由于Pt的价格比较昂贵使得成本提升,为此如何在确保催化性能不降低的情况下有效降低Pt的用量来降低成本成为研究的热点。当前主要是在Pt催化剂的基础上添加贱金属元素,以此来形成新型的Pt基催化剂。本文主要通过离子束溅射技术(IBS)制备一定沉积温度下的PtCu/C梯度催化剂薄膜,以此来探究沉积温度对双金属催化剂催化性能的影响。通过电化学循环伏安法(CV)和线性扫描伏安法(LSV)对催化剂薄膜性能进行表征;采用电感耦合等离子体发射光谱(IPC-AES)、X射线衍射(XRD)、高分辨透射电镜(HR-TEM)对催化剂样品的成分、物相、表面形貌进行表征;采用场发射扫描电镜(FESEM)对催化剂颗粒在Nafion膜表面孔道形态进行表征;通过苯加氢装置对PtCu/C/Nafion复合催化剂加氢性能进行测试。结果表明:(1)电化学性能随沉积温度呈现先增后减的特征,即随着沉积温度的升高,电化学性能先增强,当沉积温度达到250℃后,随沉积温度的继续升高,性能反而下降。与常温条件下制备的C和C1样品相比,腐蚀前的最大增长率为18.03%,腐蚀处理改性后的最大增长率为33.63%。,通过Z4和ZS4与常温纯Pt/C相比,其i0值分别增长10.1%和64.7%(常温Pt/C的i0值为0.003 901 A/cm2),具有较高的实用性。275℃沉积温度经过后处理改性的性能与250℃的性能相接近,因此对于梯度双金属PtCu催化剂薄膜适宜的沉积温度为250～275 ℃。(2)采用三次超声波震荡分散处理和超声自然沉积的方式,能够使催化剂颗粒的整体分布随着液面高度逐渐下降,颗粒均匀化程度逐渐增加,且形成结构紧凑,催化剂颗粒大小均一,分布均匀的PtCu/C/Nafion膜电极结构。(3)通过在-0.3V电解电压下的苯加氢测试表明,与常温条件下的纯Pt样相比,250℃沉积温度下的纯Pt样和双金属梯度PtCu样,其加氢效率分别提升了 62.32%和63.86%;PtCu梯度膜电极的加氢性能对比表明250℃制备的较常温制备的提升17.56%,而250℃制备的PtCu梯度膜电极经后处理改性仅提升3.92%,说明沉积温度对膜电极苯加氢效率的影响要强于后处理改性过程。
[Abstract]:Precious metal Pt has been applied in various industries because of its high catalytic activity, good corrosion resistance, oxidation resistance and stability, but because of the high price of Pt, how to effectively reduce the amount of Pt to reduce the cost has become the focus of research. At present, a new type of Pt based catalyst is formed by adding base metal elements to Pt catalyst. In this paper, the effect of deposition temperature on the catalytic performance of bimetallic catalysts was investigated by preparing PtCu/C gradient catalyst thin films at a certain deposition temperature by ion beam sputtering (IBS). The properties of the catalyst thin films were characterized by electrochemical cyclic Voltammetric method (CV) and linear scanning Voltammetric method (LSV), the composition, phase and surface morphology of the catalyst samples were characterized by inductively coupled plasma emission spectroscopy (IPC-AES) and X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), and the pore morphology of the catalyst particles on the surface of Nafion film was characterized by field emission scanning electron microscope (FESEM). The hydrogenation performance of PtCu/C/Nafion composite catalyst was tested by benzene hydrogenation unit. The results show that: (1) the electrochemical performance increases at first and then decreases with the deposition temperature, that is, with the increase of deposition temperature, the electrochemical performance increases first, and when the deposition temperature reaches 250 鈩，
本文编号：2503890
[Abstract]:Precious metal Pt has been applied in various industries because of its high catalytic activity, good corrosion resistance, oxidation resistance and stability, but because of the high price of Pt, how to effectively reduce the amount of Pt to reduce the cost has become the focus of research. At present, a new type of Pt based catalyst is formed by adding base metal elements to Pt catalyst. In this paper, the effect of deposition temperature on the catalytic performance of bimetallic catalysts was investigated by preparing PtCu/C gradient catalyst thin films at a certain deposition temperature by ion beam sputtering (IBS). The properties of the catalyst thin films were characterized by electrochemical cyclic Voltammetric method (CV) and linear scanning Voltammetric method (LSV), the composition, phase and surface morphology of the catalyst samples were characterized by inductively coupled plasma emission spectroscopy (IPC-AES) and X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM), and the pore morphology of the catalyst particles on the surface of Nafion film was characterized by field emission scanning electron microscope (FESEM). The hydrogenation performance of PtCu/C/Nafion composite catalyst was tested by benzene hydrogenation unit. The results show that: (1) the electrochemical performance increases at first and then decreases with the deposition temperature, that is, with the increase of deposition temperature, the electrochemical performance increases first, and when the deposition temperature reaches 250 鈩，
本文编号：2503890
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