Arshad Natasha, Usman Muhammad, Adnan Muhammad, Ahsan Muhammad Tayyab, Rehman Mah Rukh, Javed Sofia, Ali Zeeshan, Akram Muhammad Aftab, Demopoulos George P, Mahmood Asif
Department of Physics, Government College Women University, Sialkot 51310, Pakistan.
School of Chemical and Materials Engineering, National University of Sciences and Technology (NUST), Sector H-12, Islamabad 44000, Pakistan.
Nanomaterials (Basel). 2022 Dec 25;13(1):99. doi: 10.3390/nano13010099.
Designing multifunctional nanomaterials for high performing electrochemical energy conversion and storage devices has been very challenging. A number of strategies have been reported to introduce multifunctionality in electrode/catalyst materials including alloying, doping, nanostructuring, compositing, etc. Here, we report the fabrication of a reduced graphene oxide (rGO)-based ternary composite NiO/MnO/rGO (NMGO) having a range of active sites for enhanced electrochemical activity. The resultant sandwich structure consisted of a mesoporous backbone with NiO and MnO nanoparticles encapsulated between successive rGO layers, having different active sites in the form of Ni-, Mn-, and C-based species. The modified structure exhibited high conductivity owing to the presence of rGO, excellent charge storage capacity of 402 F·g at a current density of 1 A·g, and stability with a capacitance retention of ~93% after 14,000 cycles. Moreover, the NMGO//MWCNT asymmetric device, assembled with NMGO and multi-wall carbon nanotubes (MWCNTs) as positive and negative electrodes, respectively, exhibited good energy density (28 Wh·kg), excellent power density (750 W·kg), and capacitance retention (88%) after 6000 cycles. To evaluate the multifunctionality of the modified nanostructure, the NMGO was also tested for its oxygen evolution reaction (OER) activity. The NMGO delivered a current density of 10 mA·cm at the potential of 1.59 V versus RHE. These results clearly demonstrate high activity of the modified electrode with strong future potential.
设计用于高性能电化学能量转换和存储设备的多功能纳米材料极具挑战性。据报道，有多种策略可在电极/催化剂材料中引入多功能性，包括合金化、掺杂、纳米结构化、复合等。在此，我们报道了一种基于还原氧化石墨烯（rGO）的三元复合材料NiO/MnO/rGO（NMGO）的制备，该材料具有一系列活性位点以增强电化学活性。所得的三明治结构由具有介孔骨架的结构组成，其中NiO和MnO纳米颗粒封装在连续的rGO层之间，具有以Ni基、Mn基和C基物种形式存在的不同活性位点。由于rGO的存在，改性结构表现出高导电性，在电流密度为1 A·g时具有402 F·g的优异电荷存储容量，并且在14,000次循环后具有约93% 的电容保持率的稳定性。此外，分别以NMGO和多壁碳纳米管（MWCNT）作为正负极组装的NMGO//MWCNT非对称器件，在6000次循环后表现出良好的能量密度（28 Wh·kg）、优异的功率密度（750 W·kg）和电容保持率（88%）。为了评估改性纳米结构的多功能性，还测试了NMGO的析氧反应（OER）活性。相对于可逆氢电极（RHE），NMGO在1.59 V的电位下提供了10 mA·cm的电流密度。这些结果清楚地证明了改性电极具有高活性和强大的未来潜力。
