Department of Chemistry, Faculty of Civil Engineering, Khulna University of Engineering & Technology, Khulna, Bangladesh.
Micro-Nano Systems Centre, Tyndall National Institute, University College Cork, Cork, Ireland.
PLoS One. 2021 Mar 11;16(3):e0248142. doi: 10.1371/journal.pone.0248142. eCollection 2021.
Multifunctional and low-cost electrode materials are desirable for the next-generation sensors and energy storage applications. This paper reports the use of pencil graphite as an electrode for dual applications that include the detection of free residual chlorine using electro-oxidation process and as an electrochemical energy storage cathode. The pencil graphite is transferred to cellulose paper by drawing ten times and applied for the detection of free residual chlorine, which shows a sensitivity of 27 μA mM-1 cm-2 with a limit of detection of 88.9 μM and linearity up to 7 mM. The sample matrix effect study for the commonly interfering ions such as NO3-, SO42-, CO32-, Cl-, HCO3- shows minimal impact on free residual chlorine detection. Pencil graphite then used after cyclic voltammogram treatment as a cathode in the aqueous Zn/Al-ion battery, showing an average discharge potential plateau of ~1.1 V, with a specific cathode capacity of ~54.1 mAh g-1 at a current of 55 mA g-1. It maintains ~95.8% of its initial efficiency after 100 cycles. Results obtained from the density functional theory calculation is consistent with the electro-oxidation process involved in the detection of free residual chlorine, as well as intercalation and de-intercalation behavior of Al3+ into the graphite layers of Zn/Al-ion battery. Therefore, pencil graphite due to its excellent electro-oxidation and conducting properties, can be successfully implemented as low cost, disposable and green material for both sensor and energy-storage applications.
多功能且低成本的电极材料是下一代传感器和储能应用的理想选择。本文报道了使用铅笔石墨作为电极的双功能应用，包括通过电氧化过程检测游离余氯以及作为电化学储能阴极。通过 10 次绘图将铅笔石墨转移到纤维素纸上，用于检测游离余氯，其灵敏度为 27 μA mM-1 cm-2，检测限为 88.9 μM，线性度高达 7 mM。对常见干扰离子（如 NO3-、SO42-、CO32-、Cl-、HCO3-）的样品基质效应研究表明，其对游离余氯检测的影响最小。然后，在经过循环伏安处理后，铅笔石墨可用作水系 Zn/Al 离子电池的阴极，在 55 mA g-1 的电流下，平均放电电位平台约为 1.1 V，比容量约为 54.1 mAh g-1。经过 100 次循环后，其初始效率保持在 95.8%左右。密度泛函理论计算的结果与游离余氯检测中的电氧化过程以及 Al3+嵌入和脱嵌 Zn/Al 离子电池石墨层的行为一致。因此，由于其优异的电氧化和导电性能，铅笔石墨可以成功地用作传感器和储能应用的低成本、一次性和绿色材料。
