Preparation And Catalytic Performance Of PtCu / CeO_x / C / Nafion Membrane Electrode

Metal platinum (Pt) has excellent catalytic properties, which are often made into catalyst used in fuel cells, etc. However the price of Pt is expensive and the reserves of it is rare, so that the cost of using pure as Pt/C catalyst is higher, thus fuel cell is still can not be widely used. Seeking a low Pt loading and high catalytic performance is the hotspot in current life. Copper (Cu) and Pt are both of face-centered cubic structure, and Cu and Pt can be infinite miscibility, therefore, the Cu doped into the Pt catalyst, can form a substitution solid solution with the main phase catalytic Pt. Rare earth element has a unique catalytic properties, and it can make synergistic catalytic action with main phase catalytic Pt to enhance the catalytic performance of the catalyst.For this study, PtCu/C membrane catalysts were prepared by ion beam sputtering (IBS), they were post-processed by 400 ℃ vacuum annealing in combination with 0.5 mol/L H2SO4 acid etching. Through electrochemical CV, LSV testing and ICP-AES detection, the Pt loading of PtCu/C fell by 8.77% compared with original sample, and its electrochemical catalyzed hydrogen evolution performance improved by 20.62%. Compared with the traditional Pt/C catalyst, the Pt loading of post-processed PtCu/C fell by 62.32%, and the catalytic performance increase 9.49%. measured by the HRTEM and AFM film after post-processing of PtCu/C catalyst surface a kind of honeycomb nano porous structure, and the XRD test shows, vacuum heat treatment can enhance the degree of alloying platinum copper alloy. High resolution transmission electron microscopy (HRTEM & STEM) and atomic force microscope (AFM) were employed to characterize the surface morphology of samples and found the surface of post-processed PtCu/C exhibits honeycomb nano-porous structure. And the alloying degree of Pt and Cu was determined by the X-ray diffraction (XRD).Composite membrane catalysts of PtCu/CeOx/C was also prepared by IBS and they were also post-processed by 400 ℃ vacuum annealing in combination with 0.5 mol/L H2SO4 acid etching. Through electrochemical CV, LSV, ICP-AES, XRD and HRTEM detection, it was shows that the addition of rare earth element additives (CeOx) makes further enhance the alloying degree, from the original Pt1Cu1 into Pt1Cu3, and formed CeCu alloy. At the same time, the surface of post-processed PtCu/CeOx/C appears "bridging" structure. The electrochemical hydrogen evolution performance of PtCu/CeOx/C increased 36.07% in contrast PtCu/C and 48.97% compared with Pt/C, and the potential of hydrogen peak was moved positive by 2.14% and 2.97%, respectively, showed a low energy consumption, high electrochemical catalytic activity of hydrogen evolution performance.Get the PtCu/CeOx/C catalyst powder way through mechanical scratch. And then placed the powder into the Nafion+normal propyl alcohol solution with ultrasonic dispersion(7.5h,80w). After ultrasonic dispersion, the particles maintain its high specific surface area morphology, and the particle size reduced to 30-300nm, and keeping "bridging" surface morphology. The nano size and the surface morphology of porous particles will help to further enhance the catalytic performance of the catalyst.