Yahya N, Kamarudin S K, Karim N A, Basri S, Zanoodin A M
Fuel Cell Institute, Universiti Kebangsaan Malaysia, UKM, 43600, Bangi, Selangor, Malaysia.
Malaysian Institute of Chemical and Bioengineering Technology, Universiti Kuala Lumpur, Melaka, Malaysia.
Nanoscale Res Lett. 2019 Feb 11;14(1):52. doi: 10.1186/s11671-019-2871-8.
The aim of this study was to synthesize, characterize, and observe the catalytic activity of PdAu supported by vapor-grown carbon nanofiber (VGCNF) anode catalyst prepared via the chemical reduction method. The formation of the single-phase compounds was confirmed by X-ray diffraction (XRD) and Rietveld refinement analysis, which showed single peaks corresponding to the (111) plane of the cubic crystal structure. Further analysis was carried out by field emission scanning emission microscopy (FESEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption measurements, and X-ray photoelectron spectroscopy (XPS). The electrochemical performance was examined by cyclic voltammetry tests. The presence of mesoporous VGCNF as support enables the use of a relatively small amount of metal catalyst that still produces an excellent current density (66.33 mA cm). Furthermore, the assessment of the kinetic activity of the nanocatalyst using the Tafel plot suggests that PdAu/VGCNF exerts a strong electrocatalytic effect in glycerol oxidation reactions. The engineering challenges are apparent from the fact that the application of the homemade anode catalyst to the passive direct glycerol fuel cell shows the power density of only 3.9 mW cm. To understand the low performance, FESEM observation of the membrane electrode assembly (MEA) was carried out, examining several morphological defects that play a crucial role and affect the performance of the direct glycerol fuel cell.
本研究的目的是合成、表征并观察通过化学还原法制备的气相生长碳纳米纤维（VGCNF）负载的PdAu阳极催化剂的催化活性。通过X射线衍射（XRD）和Rietveld精修分析确认了单相化合物的形成，结果显示对应于立方晶体结构（111）面的单峰。通过场发射扫描电子显微镜（FESEM）、能量色散X射线分析（EDX）、氮吸附/脱附测量以及X射线光电子能谱（XPS）进行了进一步分析。通过循环伏安测试考察了电化学性能。作为载体的介孔VGCNF的存在使得能够使用相对少量的金属催化剂，该催化剂仍能产生优异的电流密度（66.33 mA cm）。此外，使用塔菲尔曲线对纳米催化剂的动力学活性进行评估表明，PdAu/VGCNF在甘油氧化反应中具有很强的电催化作用。从将自制阳极催化剂应用于被动式直接甘油燃料电池仅显示出3.9 mW cm的功率密度这一事实可以明显看出工程方面的挑战。为了解其低性能表现，对膜电极组件（MEA）进行了FESEM观察，检查了几个起关键作用并影响直接甘油燃料电池性能的形态缺陷。
