Abstract In this study, size control of carbon-encapsulated nickel nanoparticles (CENiNPs) synthesized by direct thermal decomposition of Ni(CH3COO)2.4H2O (NiAc) was possible by varying systematically the initial amount of the precursor during its pyrolysis. The reaction was conducted inside a thermogravimetric analyzer coupled to a quadrupole mass spectrometer for evolved gas analysis. By heating non-isothermally different initial amounts of NiAc (100–400 mg) in an argon flow at 10 °C/min from room temperature to 500 °C, CENiNPs were readily obtained, in which a thin layer of carbon resulting from the breakdown of the anion protects their metallic core from spontaneous oxidation. High resolution transmission electron microscopy and methane catalytic decomposition tests revealed that this encapsulating layer can also exert a significant role in the control of the size distribution (40–140 nm) and catalytic activity of the resultant CENiNPs. Temperature programmed oxidation of the CENiNPs identified preliminary some surface carbon species responsible for the packing of the catalytically-active metallic core. This simple and cost-effective method emerges as a competitive way to manufacture and conserve highly active CENiNPs.

中文翻译：

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通过四水醋酸镍热解合成尺寸可调的碳包覆镍纳米粒子

摘要 在这项研究中，通过在热解过程中系统地改变前驱体的初始量，可以控制通过 Ni(CH3COO)2.4H2O (NiAc) 直接热分解合成的碳包覆镍纳米粒子 (CENiNPs) 的尺寸。反应在与四极杆质谱仪联用的热重分析仪内进行，用于分析逸出气体。通过在氩气流中以 10°C/min 从室温加热至 500°C，非等温不同初始量的 NiAc（100–400 mg），很容易获得 CENiNPs，其中由分解产生的薄碳层阴离子保护它们的金属核免受自发氧化。高分辨率透射电子显微镜和甲烷催化分解测试表明，该封装层还可以在控制所得 CENiNPs 的尺寸分布（40-140 nm）和催化活性方面发挥重要作用。CENiNP 的程序升温氧化初步确定了一些负责催化活性金属核填充的表面碳物种。这种简单且具有成本效益的方法成为制造和保存高活性 CENiNP 的一种有竞争力的方法。