Amalgamation of MnWO4 nanorods with amorphous carbon nanotubes for highly stabilized energy efficient supercapacitor electrodes

State-of-the-Art Review on Amorphous Carbon Nanotubes: Synthesis, Structure, and Application

Carbon nanotubes (CNTs) have rapidly received increasing attention and great interest as potential materials for energy storage and catalyst fields, which is due to their unique physicochemical and electrical properties. With continuous improvements in fabrication routes, CNTs have been modified with various types of materials, opening up new perspectives for research and state-of-the-art technologies. Amorphous CNTs (aCNTs) are carbon nanostructures that are distinctively different from their well-ordered counterparts, such as single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs, respectively), while the atoms in aCNTs are grouped in a disordered, crystalline/non-crystalline manner. Owing to their unique structure and properties, aCNTs are attractive for energy storage, catalysis, and aerospace applications. In this review, we provide an overview of the synthetic routes of aCNTs, which include chemical vapor deposition, catalytic pyrolysis, and arc discharge. Detailed morphologies of aCNTs and the systematic elucidation of tunable properties are also summarized. Finally, we discuss the future perspectives as well as associated challenges of aCNTs. With this review, we aim to encourage further research for the widespread use of aCNTs in industry.

Synthesis of active-site rich molybdenum-doped manganese tungstate nanocubes for effective electrochemical sensing of the antiviral drug (COVID-19) nitazoxanide

Nitazoxanide (NTZ), a promising antiviral agent, is currently being tested in clinical trials as a potential treatment for novel coronavirus disease 2019 (COVID -19). This paper describes a one-pot hydrothermal synthesis to prepare molybdenum (Mo)-doped manganese tungstate nanocubes (Mo-MnWO4 NCs) for the electrochemical sensing of NTZ. The as-prepared Mo-MnWO4 NCs were characterized using various techniques such as XRD, Raman, FE-SEM, FE-TEM, and XPS to confirm the crystal structure, morphology, and elemental composition. The obtained results demonstrate that Mo doping on MnWO4 generates many vacancy sites, exhibiting remarkable electrochemical activity. The kinetic parameters of the electrode modified with Mo-MnWO4 NCs were calculated to be (Ks) 1.1 × 10-2 cm2 s-1 and (α) 0.97, respectively. Moreover, a novel electrochemical sensor using Mo-MnWO4 NCs was fabricated to detect NTZ, which is used as a primary antibiotic to control COVID-19. Under optimal conditions, the electrochemical reduction of NTZ was determined with a low detection limit of 3.7 nM for a linear range of 0.014-170.2 μM with a high sensitivity of 0.78 μA μM-1 cm-2 and negligible interference with other nitro group-containing drugs, cations, and anions. The electrochemical sensor was successfully used to detect NTZ in the blood serum and urine samples and achieved high recoveries in the range of 94-99.2% and 95.3-99.6%, respectively. This work opens a way to develop high-performance sensing materials by exploring the introduction of defect engineering on metal tungstates to detect drug molecules for practical applications.

Synthesis of different manganese tungstate nanostructures for enhanced charge-storage applications: theoretical support for experimental findings

Due to the dual features of EDLC and pseudocapacitance the low-temperature developed MnWO4 nanostructures with different aspect ratio showed good electrochemical properties. DFT study provided the quantum capacitance value.

Hydrothermal Synthesis of MnWO4@GO Composite as Non-Precious Electrocatalyst for Urea Oxidation

In this study, manganese tungstate (MW) and MW/graphene oxide (GO) composites were prepared by a facile hydrothermal synthesis at pH values of 7 and 12. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used for the structural, compositional, and morphological characterization of the nanoparticles (NPs). The XRD analysis revealed that the formation of monoclinic MnWO₄ did not have impurities. The SEM and TEM analyses showed that the synthesized NPs were rod-shaped and well-distributed on the GO. The as-synthesized samples can be used as electrocatalysts for the urea oxidation reaction (UOR). The MW@GO-12 electrocatalyst exhibited higher current density values compared to other electrocatalysts. This study provides a new platform for synthesizing inexpensive nanocomposites as promising electrocatalysts for energy storage and conversion applications.