Abstract Water hyacinth (WH) is a noxious weed. Its rapid growth can clog waterways, causing widespread ecological and environmental threats as well as power generation and irrigation issues. In the present study, water hyacinth was utilized as a precursor to synthesize multiwall carbon nanotubes (MWCNTs) using a simple chemical vapor deposition method. FESEM-EDS revealed that the synthesized MWCNTs had noodle-like, dense, and rough surfaces. TEM confirmed that MWCNTs had a bamboo-like structure with the diameter of 30–40 nm, and the wall thickness of approximately 7 nm. The interlayer distance was found to be approximately 0.34 by XRD. Raman spectra displayed three major bands of MWCNTS: D-band at 1,340 cm−1, G-band at 1,596 cm−1, and (D + G)-band between 2,783 and 2,953 cm−1. The ratio of the D-to-G band intensity was 0.94 ± 0.03, indicating that the synthesized MWCNTs had well degree of graphitization. Electrochemical measurement results of the prepared MWCNTs cathode for aluminum–air battery showed that MWCNTs exhibited higher energy capacity than commercial graphite. Collectively, this study shows that water hyacinth could be used effectively as a precursor for the production of MWCNTs, thus successfully converting the noxious weed into high value-added materials.

中文翻译：

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可再生水葫芦中用作铝-空气电池阴极材料的碳纳米管的合成、表征和电化学性能

摘要 水葫芦（WH）是一种有毒杂草。它的快速增长会堵塞水道，造成广泛的生态和环境威胁以及发电和灌溉问题。在本研究中，水葫芦被用作前体，使用简单的化学气相沉积方法合成多壁碳纳米管 (MWCNT)。FESEM-EDS 显示合成的 MWCNTs 具有面条状、致密和粗糙的表面。TEM 证实 MWCNTs 具有竹状结构，直径为 30-40 nm，壁厚约为 7 nm。通过XRD发现层间距离约为0.34。拉曼光谱显示了 MWCNTS 的三个主要波段：1,340 cm-1 处的 D 波段、1,596 cm-1 处的 G 波段和 2,783 和 2,953 cm-1 之间的 (D + G) 波段。D-G 带强度比为 0.94 ± 0.03，表明合成的 MWCNTs 具有良好的石墨化程度。制备的铝空气电池用多壁碳纳米管阴极的电化学测量结果表明多壁碳纳米管比商业石墨具有更高的能量容量。总的来说，这项研究表明，水葫芦可以有效地用作生产多壁碳纳米管的前体，从而成功地将有害杂草转化为高附加值材料。