Synthesis, characterizations, and electrochemical studies of ZnO/reduced graphene oxide nanohybrids for supercapacitor application

Herein the present article reports the fabrication of ZnO/reduced graphene oxide (ZnG) nanohybrid following a reduction-based process using a non-hazardous material, i.e., ascorbic acid. The morphology, structure, and bonding in the nanohybrid were analyzed using different techniques. Atomic force mi-croscopy and scanning electron microscopy images show spherical particles of ZnO distributed over reduced graphene oxide (rGO). The X-ray diffraction analysis gives calculated values of crystallite size for ZnO as 15.62 nm. The successful incorporation of ZnO nanoparticles into rGO was confirmed using en-ergy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy analyses. The electrochemical studies were performed using an electrolyte (0.5 M H2SO4). The calculated value of specific capacitance for the nanohybrid was 345 Fg(-1), which was found to be almost double as compared to that of rGO, which is having a value of only 190.5 Fg(-1) at the same scan rate. The nanohybrid also showed excellent capacitance retention after 1,000 cycles. (C) 2021 Elsevier Ltd. All rights reserved.