Abstract Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized at various temperatures ranging from 650 to 950°C, at 100°C intervals, by chemical vapor deposition technique (CVD). The synthesized N-CNTs were employed as modifiers of glassy carbon paste electrodes (GCPE), which were further used as electrochemical sensors for the determination of dopamine (DA) and epinephrine (EP), two important catecholamines that display biological roles as neurotransmitters and hormones. The results revealed that electrodes modified with the N-CNTs synthesized at 650°C (GCPE/N-CNT650) and 950°C (GCPE/N-CNT950) presented better electrocatalytic activities and sensing capabilities than the others (GCPE/N-CNT750 and GCPE/N-CNT850). N-CNT950 had the highest graphitization and the highest powder conductivity, whereas N-CNT650 had the lowest graphitization and the lowest powder conductivity. However, both N-CNT950 and N-CNT650 had the highest nitrogen contents, 3.5 and 3.8 at.%, respectively, which probably enhanced their number of electroactive sites to interact with DA and EP molecules. This result is of high significance, because the use of the lowest temperature (650°C) in the CVD process, yielded N-CNTs with improved electrocatalytic activity and less energy consumption during CVD.

中文翻译：

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氮掺杂碳纳米管对电化学传感的影响：合成温度的影响

摘要 通过化学气相沉积技术 (CVD) 在 650 至 950°C 的各种温度下以 100°C 的间隔合成氮掺杂碳纳米管 (N-CNT)。合成的 N-CNTs 被用作玻璃碳糊电极 (GCPE) 的改性剂，进一步用作电化学传感器，用于测定多巴胺 (DA) 和肾上腺素 (EP)，这两种重要的儿茶酚胺具有神经递质和激素的生物学作用. 结果表明，用在 650°C (GCPE/N-CNT650) 和 950°C (GCPE/N-CNT950) 合成的 N-CNT 修饰的电极比其他电极 (GCPE/N-CNT750) 表现出更好的电催化活性和传感能力和 GCPE/N-CNT850）。N-CNT950具有最高的石墨化和最高的粉末电导率，而 N-CNT650 具有最低的石墨化和最低的粉末电导率。然而，N-CNT950 和 N-CNT650 的氮含量最高，分别为 3.5 和 3.8 at.%，这可能增加了它们与 DA 和 EP 分子相互作用的电活性位点的数量。这一结果具有重要意义，因为在 CVD 过程中使用最低温度 (650°C)，产生的 N-CNT 具有更高的电催化活性和更低的 CVD 能耗。