Flores-Lasluisa Jhony Xavier, Cazorla-Amorós Diego, Morallón Emilia
Department Química Física e Instituto Universitario de Materiales, Universidad de Alicante, Ap. 99, E-03080 Alicante, Spain.
Department Química Inorgánica e Instituto Universitario de Materiales, Universidad de Alicante, Ap. 99, E-03080 Alicante, Spain.
Nanomaterials (Basel). 2024 Aug 24;14(17):1381. doi: 10.3390/nano14171381.
Defect-containing carbon nanotube materials were prepared by subjecting two commercial multiwalled carbon nanotubes (MWCNTs) of different purities to purification (HCl) and oxidative conditions (HNO) and further heat treatment to remove surface oxygen groups. The as-prepared carbon materials were physicochemically characterized to observe changes in their properties after the different treatments. TEM microscopy shows morphological modifications in the MWCNTs after the treatments such as broken walls and carbon defects including topological defects. This leads to both higher surface areas and active sites. The carbon defects were analysed by Raman spectroscopy, but the active surface area (ASA) and the electrochemical active surface area (EASA) values showed that not all the defects are equally active for oxygen reduction reactions (ORRs). This suggests the importance of calculating either ASA or EASA in carbon materials with different structures to determine the activity of these defects. The as-prepared defect-containing multiwalled carbon nanotubes exhibit good catalytic performance due to the formation of carbon defects active for ORR such as edge sites and topological defects. Moreover, they exhibit good stability and methanol tolerances. The as-prepared MWCNTs sample with the highest purity is a promising defective carbon material for ORR because its activity is only related to high concentrations of active carbon defects including edge sites and topological defects.
通过对两种不同纯度的商用多壁碳纳米管（MWCNTs）进行纯化（HCl）和氧化处理（HNO），并进一步进行热处理以去除表面含氧基团，制备了含缺陷的碳纳米管材料。对制备的碳材料进行物理化学表征，以观察不同处理后其性能的变化。透射电子显微镜（TEM）显示处理后的MWCNTs在形态上有改变，如管壁破裂和包括拓扑缺陷在内的碳缺陷。这导致了更高的表面积和活性位点。通过拉曼光谱对碳缺陷进行了分析，但活性表面积（ASA）和电化学活性表面积（EASA）值表明，并非所有缺陷对氧还原反应（ORR）都具有同等活性。这表明在具有不同结构的碳材料中计算ASA或EASA对于确定这些缺陷的活性很重要。所制备的含缺陷多壁碳纳米管由于形成了对ORR具有活性的碳缺陷（如边缘位点和拓扑缺陷）而表现出良好的催化性能。此外，它们还表现出良好的稳定性和甲醇耐受性。所制备的纯度最高的MWCNTs样品是一种很有前景的用于ORR的缺陷碳材料，因为其活性仅与包括边缘位点和拓扑缺陷在内的高浓度活性碳缺陷有关。
