Hu Xiaoxian, Min Xiaobo, Li Xinyu, Si Mengying, Liu Lu, Zheng Junhao, Yang Weichun, Zhao Feiping
Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China.
Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China.
J Colloid Interface Sci. 2022 Jun 15;616:389-400. doi: 10.1016/j.jcis.2022.02.098. Epub 2022 Feb 22.
Capacitive deionization (CDI) has gained increasing attention as an environmentally friendly and energy-efficient technology for brackish water desalination. However, traditional CDI electrodes still suffer from low salt adsorption capacity and unsatisfactory reusability, which inhibit its application for long-term operations. Herein, we present a facile and effective approach to prepare Co and CoO nanoparticles co-incorporating nitrogen-doped (N-doped) carbon nanotubes (Co-CoO/N-CNTs) via a pyrolysis route. The Co-CoO nanoparticles were homogeneously in-situ encapsulated in the inner channels of the conductive CNTs to form a novel and efficient CDI electrode for the first time. The encapsulation of Co-CoO nanoparticles in CNTs not only inhibits the Co leaching but also significantly enhances the desalination capacity. The morphology, structure, and capacitive desalination properties of the Co-CoO/N-CNTs were thoroughly characterized to illuminate the nano-confinement effects and the key roles of the interaction between cobalt species in the CDI performance. The co-existing metallic cobalt and cobalt oxides act as the roles of effective active sites in the CDI performance. As a consequence, the optimum Co-CoO/N-CNTs electrode displays an outstanding desalination capacity of 66.91 mg NaCl g at 1.4 V. This work provides insights for understanding the nano-confinement effects and the key roles of the interaction between cobalt species on the CDI performance.
电容去离子化（CDI）作为一种用于微咸水脱盐的环境友好且节能的技术，已受到越来越多的关注。然而，传统的CDI电极仍然存在低盐吸附容量和不理想的可重复使用性问题，这限制了其在长期运行中的应用。在此，我们提出了一种简便有效的方法，通过热解路线制备共掺入氮掺杂（N掺杂）碳纳米管（Co-CoO/N-CNTs）的钴和氧化钴纳米颗粒。首次将Co-CoO纳米颗粒均匀地原位封装在导电碳纳米管的内通道中，形成了一种新型高效的CDI电极。Co-CoO纳米颗粒封装在碳纳米管中不仅抑制了钴的浸出，还显著提高了脱盐能力。对Co-CoO/N-CNTs的形貌、结构和电容去离子化性能进行了全面表征，以阐明纳米限域效应以及钴物种之间的相互作用在CDI性能中的关键作用。共存的金属钴和氧化钴在CDI性能中起到了有效活性位点的作用。因此，最佳的Co-CoO/N-CNTs电极在1.4 V时显示出66.91 mg NaCl g的出色脱盐能力。这项工作为理解纳米限域效应以及钴物种之间的相互作用在CDI性能中的关键作用提供了见解。
