A Review of Recent Progress on Nano MnO2: Synthesis, Surface Modification and Applications

This review highlights the synthesis, structure modification, morphology, and properties of nano manganese dioxide (MnO2). Though MnO2 has been widely employed for electrode materials due to its superior electrochemica1 performance, abundant storage, low cost, and environmental friendly nature, the usage in bioapplications and dye mineralisation studies have started since few decades only. Currently, nano MnO2 plays an important role in solar cell devices and gas sensing as it can be easily tunable into desired polymerphic structure and morphology. Herein, the use of nano MnO2 as advanced material in energy, gas sensing, biological application and wastewater remediation are described. Based on the recent research, the available preparation procedures, surface modification and applications of nanostructured MnO2 are systematically presented. Also, structure stabilization and performance improvement of nano MnO2 by doping or composite formation with metals, carbon materials, and conductive polymers are summerised. According to the latest research progress, new trends and strategies of nano MnO2 towards specific applications besides energy storage application are focused in this review, as well as a brief overview of the challenges and future perspectives of MnO2, synthetic methodologies, and their state-of-the-art applications in different fields are presented.