A simple wet-chemical synthesis, reaction mechanism, and charge storage application of cobalt oxide electrodes of different morphologies

From green chemistry to biomedicine: the sustainable symphony of cobalt oxide nanoparticles

Deciphering the importance of nanostructures in advanced technologies for a broad application spectrum has far-reaching implications for humans and the environment. Cost-effective, abundant cobalt oxide nanoparticles (NPs) are among the most attractive and extensively utilized materials in biomedical sciences due to their high chemical stability, and biocompatibility. However, the methods used to develop the NPs are hazardous for human health and the environment. This article precisely examines diverse green synthesis methods employing plant extracts and microbial sources, shedding light on their mechanism, and eco-friendly attributes with more emphasis on biocompatible properties accompanied by their challenges and avenues for further research. An in-depth analysis of the synthesized cobalt oxide NPs by various characterization techniques reveals their multifaceted functionalities including cytotoxicity, larvicidal, antileishmanial, hemolytic, anticoagulating, thrombolytic, anticancer and drug sensing abilities. This revelatory and visionary article helps researchers to contribute to advancing sustainable practices in nanomaterial synthesis and illustrates the potential of biogenically derived cobalt oxide NPs in fostering green and efficient technologies for biomedical applications.

Recent developments in polypyrrole/manganese oxide-based nanocomposites for thin film electrodes in supercapacitors: a minireview

This review article highlights the recent developments in the synthesis and electrochemical performance of polypyrrole/manganese oxide thin-film electrodes synthesized by various chemical methods for supercapacitor applications. In the class of conducting polymers for electrode applications, polypyrrole (Ppy) is considered an important polymer due to its low cost and abundance. Ppy's polymeric composition and structural properties, however, pose stability concerns and have a drawback of a short life cycle over long-term charge-discharge processes, limiting its potential for industrial and commercial utilization. Recently, manganese oxide (MnO2) has been actively explored as a supercapacitor electrode material due to its low cost, high theoretical specific capacitance and abundance. Ppy/MnO2 thin film electrodes revealed high specific capacitance and stability, making them excellent candidates for next-generation supercapacitor electrode materials.

Room-temperature synthesis and CO2-gas sensitivity of bismuth oxide nanosensors

Room-temperature (27 °C) synthesis and carbon dioxide (CO₂)-gas-sensor applications of bismuth oxide (Bi₂O₃) nanosensors obtained via a direct and superfast chemical-bath-deposition method (CBD) with different surface areas and structures, i.e., crystallinities and morphologies including a woollen globe, nanosheet, rose-type, and spongy square plate on a glass substrate, are reported. Moprhologies of the Bi₂O₃ nanosensors are tuned through polyethylene glycol, ethylene glycol, and ammonium fluoride surfactants. The crystal structure, type of crystallinity, and surface appearance are determined from the X-ray diffraction patterns, X-ray photoelectron spectroscopy spectra, and high-resolution transmission electron microscopy images. The room-temperature gas-sensor applications of these Bi₂O₃ nanosensors for H₂, H₂S, NO₂, SO_2, and CO₂ gases are monitored from 10 to 100 ppm concentrations, wherein Bi₂O₃ nanosensors of different physical properties demonstrate better performance and response/recovery time measurement for CO₂ gas than those for the other target gases employed. Among various sensor morphologies, the nanosheet-type Bi₂O₃ sensor has exhibited at 100 ppm concentration of CO₂ gas, a 179% response, 132 s response time, and 82 s recovery time at room-temperature, which is credited to its unique surface morphology, high surface area, and least charge transfer resistance. This suggests that the importance of the surface morphology, surface area, and crystallinity of the Bi₂O₃ nanosensors used for designing room-temperature operable CO₂ gas sensors for commercial benefits.

Room-temperature (27 °C) synthesis and carbon dioxide (CO₂)-gas-sensing applications of bismuth oxide (Bi₂O₃) nanosensors obtained via a direct and superfast chemical-bath-deposition method (CBD) with different surface areas and structures.