In the present study, CeO quantum dots (QDs) were synthesized by microplasma discharge method out of cerium nitrate precursor suspension using argon gas as plasma medium. The highly energetic electrons in the microplasma plume generate highly reactive metastable OH radicals, which further combine with electrons to form OH and react with the cerium ions (III) in the precursor solution to form CeO QDs. The radical produced during the process was recorded using optical emission spectroscopy. The structural features, oxidation states, morphology, elemental composition and surface area of the synthesized QDs were identified by XRD, Raman, XPS, FE-SEM, HR-TEM, EDS, PL and BET analysis, respectively. The results obtained revealed the formation of cubic phase CeO QDs, which was confirmed by XRD and Raman analysis. Agglomerated ceria QDs of spherical shape with an average size of around 5 nm were analyzed from FE-SEM and HR-TEM observations. The electrochemical performance of CeO QDs as electrode material was investigated through cyclic voltammetry analysis by an electrochemical workstation. The material achieved a highest specific capacitance of 388 Fg at 1 Ag current density. The commendable electrochemical performance of microplasma synthesized CeO QDs was attributed to the minuscule size, high surface area and the presence of Ce ions. This study highlights the synthesis of CeO QDs through a single, rapid and amicable process without the use of secondary treatments and suggests the use of CeO as a good electrode material for electrochemical applications.

中文翻译：

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用于超级电容器应用的微等离子体放电法快速一步合成二氧化铈量子点

在本研究中，使用氩气作为等离子体介质，通过微等离子体放电法从硝酸铈前驱体悬浮液中合成了CeO量子点（QD）。微等离子体羽流中的高能电子产生高反应性亚稳态OH自由基，其进一步与电子结合形成OH并与前驱体溶液中的铈离子(III)反应形成CeO量子点。使用光学发射光谱记录该过程中产生的自由基。通过 XRD、Raman、XPS、FE-SEM、HR-TEM、EDS、PL 和 BET 分析分别鉴定了合成 QD 的结构特征、氧化态、形貌、元素组成和表面积。所得结果揭示了立方相 CeO QD 的形成，并通过 XRD 和拉曼分析证实了这一点。通过 FE-SEM 和 HR-TEM 观察分析了平均尺寸约为 5 nm 的球形团聚二氧化铈量子点。通过电化学工作站的循环伏安分析研究了CeO量子点作为电极材料的电化学性能。该材料在 1 Ag 电流密度下实现了 388 Fg 的最高比电容。微等离子体合成的 CeO 量子点具有值得称赞的电化学性能，这归因于其微小的尺寸、高表面积和 Ce 离子的存在。这项研究强调了通过单一、快速和友好的过程合成 CeO 量子点，无需使用二次处理，并建议使用 CeO 作为电化学应用的良好电极材料。