Sustainable synthesis of organic framework-derived ZnO nanoparticles for fabrication of supercapacitor electrode

The phytosynthesis of metal oxides nanoparticles (NPs) has been extensively reported; yet mechanism involved and incorporated bioactive compounds in the synthesized NPs are still need to be investigated. In this regard, here an efficient sustainable co-precipitation synthesis of zinc oxide nanoparticles (ZnO NPs) has been developed, employing hydrothermal reactions, using organic compounds ofNasturtium officinaleleaves. Pure hexagonal wurtzite ZnO was identified by X-ray diffraction and NPs in the size range of 50-60 nm were observed by field emission scanning electron microscopy. X-ray photoelectron spectroscopy revealed surface modification of ZnO by functional groups associated with the incorporated bio active compounds ofNasturtium officinale. The phyto-functionalized ZnO NPs having anoptical direct band gap of 3.29 eV and optical band gap energy of 2.85 eV were evaluated by cyclic voltammetry at various scan rates, galvanostatic charge-discharge at a range of current densities and electrochemical impedance spectroscopy (Z ' vs. Z '' and Z vs. frequency) in aqueous electrolyte. The fabricated ZnO-based electrode revealed a specific capacitance of 86.5 F/g at 2 mV/s with 97% coulombic efficiency for 2000 cycles. The good electrochemical conductivity was demonstrated by lower internal resistance of 1.04 omega. Therefore, the present study suggested the significant potential of organic compounds incorporated ZnO NPs towards supercapacitor.

Automated summary

This study successfully synthesized zinc oxide nanoparticles using organic compounds from Nasturtium officinale leaves via a hydrothermal reaction. The synthesized nanoparticles exhibited excellent electrochemical performance, indicating the significant potential of organic compound-incorporated ZnO NPs for supercapacitors.