Selepe Cyril Tlou, Gwebu Sandile Surprise, Matthews Thabo, Mashola Tebogo Abigail, Sikeyi Ludwe Luther, Zikhali Memory, Maxakato Nobanathi Wendy
Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa.
Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Braamfontein, Johannesburg 2050, South Africa.
Nanomaterials (Basel). 2021 Oct 15;11(10):2725. doi: 10.3390/nano11102725.
Carbon nano-onions (CNOs) were successfully synthesized by employing the flame pyrolysis (FP) method, using flaxseed oil as a carbon source. The alcohol reduction method was used to prepare Pd/CNOs and Pd-Sn/CNOs electro-catalysts, with ethylene glycol as the solvent and reduction agent. The metal-nanoparticles were supported on the CNO surface without adjusting the pH of the solution. High-resolution transmission electron microscopy (HRTEM) images reveal CNOs with concentric graphite ring morphology, and also PdSn nanoparticles supported on the CNOs. X-ray diffractometry (XRD) patterns confirm that CNOs are amorphous and show the characteristic diffraction peaks of Pd. There is a shifting of Pd diffraction peaks to lower angles upon the addition of Sn compared to Pd/CNOs. X-ray photoelectron spectroscopy (XPS) results also confirm the doping of Pd with Sn to form a PdSn alloy. Fourier transform infrared spectroscopy (FTIR) displays oxygen, hydroxyl, carboxyl, and carbonyl, which facilitates the dispersion of Pd and Sn nanoparticles. Raman spectrum displays two prominent peaks of carbonaceous materials which correspond to the D and G bands. The Pd-Sn/CNOs electro-catalyst demonstrates improved electro-oxidation of methanol and ethanol performance compared to Pd/CNOs and commercial Pd/C electro-catalysts under alkaline conditions.
以亚麻籽油为碳源，采用火焰热解法成功合成了碳纳米洋葱（CNOs）。以乙二醇为溶剂和还原剂，采用醇还原法制备了Pd/CNOs和Pd-Sn/CNOs电催化剂。金属纳米颗粒负载在CNO表面，无需调节溶液的pH值。高分辨率透射电子显微镜（HRTEM）图像显示CNOs具有同心石墨环形态，并且CNOs上负载有PdSn纳米颗粒。X射线衍射（XRD）图谱证实CNOs为非晶态，并显示出Pd的特征衍射峰。与Pd/CNOs相比，添加Sn后Pd衍射峰向低角度移动。X射线光电子能谱（XPS）结果也证实了Pd与Sn掺杂形成了PdSn合金。傅里叶变换红外光谱（FTIR）显示了氧、羟基、羧基和羰基，这有利于Pd和Sn纳米颗粒的分散。拉曼光谱显示了碳质材料的两个突出峰，分别对应于D带和G带。在碱性条件下，与Pd/CNOs和商业Pd/C电催化剂相比，Pd-Sn/CNOs电催化剂表现出改善的甲醇和乙醇电氧化性能。
