A Facile Two-Step Hydrothermal Synthesis of Co(OH)2@NiCo2O4 Nanosheet Nanocomposites for Supercapacitor Electrodes.

The composites of NiCo2O4 with unique structures were substantially investigated as promising electrodes. In this study, the unique structured nanosheets anchored on nickel foam (Ni foam) were prepared under the hydrothermal technique of NiCo2O4 and subsequent preparation of Co(OH)2. The Co(OH)2@NiCo2O4 nanosheet composite has demonstrated higher specific capacitances owing to its excellent specific surface region, enhanced rate properties, and outstanding electrical conductivities. Moreover, the electrochemical properties were analyzed in a three-electrode configuration to study the sample material. The as-designed Co(OH)2@NiCo2O4 nanosheet achieves higher specific capacitances of 1308 F·g-1 at 0.5 A·g-1 and notable long cycles with 92.83% capacity retention over 6000 cycles. The Co(OH)2@NiCo2O4 nanosheet electrode exhibits a long life span and high capacitances compared with the NiCo2O4 and Co(OH)2 electrodes, respectively. These outstanding electrochemical properties are mainly because of their porous construction and the synergistic effects between NiCo2O4 and Co(OH)2. Such unique Co(OH)2@NiCo2O4 nanosheets not only display promising applications in renewable storage but also reiterate to scientists of the unlimited potential of high-performance materials.

Facile Synthesis of Battery-Type CuMn2O4 Nanosheet Arrays on Ni Foam as an Efficient Binder-Free Electrode Material for High-Rate Supercapacitors.

The development of battery-type electrode materials with hierarchical nanostructures has recently gained considerable attention in high-rate hybrid supercapacitors. For the first time, in the present study novel hierarchical CuMn2O4 nanosheet arrays (NSAs) nanostructures are developed using a one-step hydrothermal route on a nickel foam substrate and utilized as an enhanced battery-type electrode material for supercapacitors without the need of binders or conducting polymer additives. X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques are used to study the phase, structural, and morphological characteristics of the CuMn2O4 electrode. SEM and TEM studies show that CuMn2O4 exhibits a nanosheet array morphology. According to the electrochemical data, CuMn2O4 NSAs give a Faradic battery-type redox activity that differs from the behavior of carbon-related materials (such as activated carbon, reduced graphene oxide, graphene, etc.). The battery-type CuMn2O4 NSAs electrode showed an excellent specific capacity of 125.56 mA h g-1 at 1 A g-1 with a remarkable rate capability of 84.1%, superb cycling stability of 92.15% over 5000 cycles, good mechanical stability and flexibility, and low internal resistance at the interface of electrode and electrolyte. Due to their excellent electrochemical properties, high-performance CuMn2O4 NSAs-like structures are prospective battery-type electrodes for high-rate supercapacitors.

Recent Advancements of Polyaniline/Metal Organic Framework (PANI/MOF) Composite Electrodes for Supercapacitor Applications: A Critical Review.

Supercapacitors (SCs), also known as ultracapacitors, should be one of the most promising contenders for meeting the needs of human viable growth owing to their advantages: for example, excellent capacitance and rate efficiency, extended durability, and cheap materials price. Supercapacitor research on electrode materials is significant because it plays a vital part in the performance of SCs. Polyaniline (PANI) is an exceptional candidate for energy-storage applications owing to its tunable structure, multiple oxidation/reduction reactions, cheap price, environmental stability, and ease of handling. With their exceptional morphology, suitable functional linkers, metal sites, and high specific surface area, metal-organic frameworks (MOFs) are outstanding materials for electrodes fabrication in electrochemical energy storage systems. The combination of PANI and MOF (PANI/MOF composites) as electrode materials demonstrates additional benefits, which are worthy of exploration. The positive impacts of the two various electrode materials can improve the resultant electrochemical performances. Recently, these kinds of conducting polymers with MOFs composites are predicted to become the next-generation electrode materials for the development of efficient and well-organized SCs. The recent achievements in the use of PANI/MOFs-based electrode materials for supercapacitor applications are critically reviewed in this paper. Furthermore, we discuss the existing issues with PANI/MOF composites and their analogues in the field of supercapacitor electrodes in addition to potential future improvements.

Facile Fabrication of MnCo2O4/NiO Flower-Like Nanostructure Composites with Improved Energy Storage Capacity for High-Performance Supercapacitors.

Over the past few decades, the application of new novel materials in energy storage system has seen excellent development. We report a novel MnCo2O4/NiO nanostructure prepared by a simplistic chemical bath deposition method and employed it as a binder free electrode in the supercapacitor. The synergistic attraction from a high density of active sites, better transportation of ion diffusion and super-most electrical transportation, which deliver boost electrochemical activities. X-ray diffraction, field-emission scanning electron microscopy, and X-ray photoelectron spectroscopy have been used to investigate the crystallinity, morphology, and elemental composition of the as-synthesized precursors, respectively. Cyclic voltammetry, galvanostatic charge/discharge, and electron impedance spectroscopy have been employed to investigate the electrochemical properties. The unique nanoparticle structures delivered additional well-organized pathways for the swift mobility of electrons and ions. The as-prepared binder-free MnCo2O4/NiO nanocomposite electrode has a high specific capacity of 453.3 C g-1 at 1 Ag-1, and an excellent cycling reliability of 91.89 percent even after 4000 cycles, which are significantly higher than bare MnCo2O4 and NiO electrodes. Finally, these results disclose that the as-fabricated MnCo2O4/NiO electrode could be a favored-like electrode material holds substantial potential and supreme option for efficient supercapacitor and their energy storage-related applications.

Metal sensing-carbon dots loaded TiO2-nanocomposite for photocatalytic bacterial deactivation and application in aquaculture.

Nowadays, bioactive nanomaterials have been attracted the researcher's enthusiasm in various fields. Herein, Diplocyclos palmatus leaf extract-derived green-fluorescence carbon dots (DP-CDs) were prepared using the hydrothermal method. Due to the strong fluorescence stability, the prepared DP-CDs were coated on filter-paper to make a fluorometric sensor-strip for Fe3+ detection. After, a bandgap-narrowed DP-CDs/TiO2 nanocomposite (DCTN) was prepared using the methanolic extract of D. palmatus. The prepared DCTN exhibited improved photocatalytic bacterial deactivation under sunlight irradiation. The DCTN-photocatalysis slaughtered V. harveyi cells by the production of reactive oxygen species, which prompting oxidative stress, damaging the cell membrane and cellular constituents. These results suggest the plausible mode of bactericidal action of DCTN-photocatalysis under sunlight. Further, the DCTN has shown potent anti-biofilm activity against V. harveyi, and thereby, DCTN extended the survival of V. harveyi-infected shrimps during the in vivo trial with Litopenaeus vannamei. Notably, this is the first report for the disinfection of V. harveyi-mediated acute-hepatopancreatic necrosis disease (AHPND) using nanocomposite. The reduced internal-colonization of V. harveyi on the hepatopancreas as well as the rescue action of the pathognomonic effect in the experimental animals demonstrated the anti-infection potential of DCTN against V. harveyi-mediated AHPND in aquaculture.

CNT@rGO@MoCuSe Composite as an Efficient Counter Electrode for Quantum Dot-Sensitized Solar Cells.

This paper reports an efficient and simple strategy for the synthesis of molybdenum copper selenide (MoCuSe) nanoparticles decorated with a combination of a carbon nanotube (CNT) network and reduced graphene oxide (rGO) nanosheets to form an integrated hybrid architecture (CNT@rGO@MoCuSe) using a two-step hydrothermal approach. The synthesized hybrid CNT@rGO@MoCuSe material onto the Ni foam substrate is applied successfully as an effective counter electrode (CE) in quantum dot-sensitized solar cells (QDSSCs). A highly conductive CNT@rGO network grown on electrochemically active MoCuSe particles provides a large surface area and exhibits a rapid electron transport rate at the interface of CE/electrolyte. As a result, the QDSSC with the designed CNT@rGO@MoCuSe CE shows a higher power conversion efficiency of 8.28% under 1 sun (100 mW cm-2) irradiation, which is almost double the efficiency of 4.04% for the QDSSC with the MoCuSe CE. Furthermore, the QDSSC based on the CNT@rGO@MoCuSe CE delivers superior stability at a working state for over 100 h. Therefore, CNT@rGO@MoCuSe is very promising as a stable and efficient CE for QDSSCs and offers new opportunities for the development of hybrid, effective, and robust materials for energy-related fields.