Browsing by Author "Ma, Yanjiao"

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    The effect of PtRuIr nanoparticle crystallinity in electrocatalytic methanol oxidation
    (MDPI, 2013) Ma, Yanjiao; Wang, Rongfang; Wang, Hui; Liao, Shijun; Key, Julian; Linkov, Vladimir; Ji, Shan
    Two structural forms of a ternary alloy PtRuIr/C catalyst, one amorphous and one highly crystalline, were synthesized and compared to determine the effect of their respective structures on their activity and stability as anodic catalysts in methanol oxidation. Characterization techniques included TEM, XRD, and EDX. Electrochemical analysis using a glassy carbon disk electrode for cyclic voltammogram and chronoamperometry were tested in a solution of 0.5 mol L−1 CH3OH and 0.5 mol L−1 H2SO4. Amorphous PtRuIr/C catalyst was found to have a larger electrochemical surface area, while the crystalline PtRuIr/C catalyst had both a higher activity in methanol oxidation and increased CO poisoning rate. Crystallinity of the active alloy nanoparticles has a big impact on both methanol oxidation activity and in the CO poisoning rate.
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    Platinum overlaid PdCulr/C: an Improved Methanol Oxidation Elextrocatalyst
    (ESG, 2013) Ma, Yanjiao; Wang, Rongfang; Wang, Hui; Ji, Shan
    A platinum overlaid PdCuIr/C (Pt-PdIrCu/C) anodic catalyst for direct methanol fuel cell was prepared by a two-step reduction method. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) results show that the metal nano-particles had a large surface area and even distribution. The Pt mass activity of the catalyst was about 6.6 times larger than that of a Pt/C catalyst and 1.2 times larger than that of a Pt-PdCu/C catalyst. The high electrocatalytic activities could be attributed to the synergistic effect between Pt and PdIrCu.
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    Synthesis of carbon-supported PdSn–SnO2 nanoparticles with different degrees of interfacial contact and enhanced catalytic activities for formic acid oxidation
    (Royal Society of Chemistry, 2013) Wang, Hui; Liu, Ziyue; Ma, Yanjiao; Julian, Key; Ji, Shan; Linkov, Vladimir; Wang, Rongfang
    The conjunction of the PdSn alloy and SnO2 is of interest for improving catalytic activity in formic acid oxidation (FAO). Here, we report the synthesis of PdSn–SnO2 nanoparticles and a study of their catalytic FAO activity. Different degrees of interfacial contact between SnO2 and PdSn were obtained using two different stabilizers (sodium citrate and EDTA) during the reduction process in catalyst preparation. Compared to the PdSn alloy, PdSn–SnO2 supported on carbon black showed enhanced FAO catalytic activity due to the presence of SnO2 species. It was also found that interfacial contact between the PdSn alloy and the SnO2 phase has an impact on the activity towards CO oxidation and FAO.