Optical, corrosion resistance and electrochemical properties of Fe3O4-Ag2O/rGO nanocomposites for supercapacitive behaviour

Abstract

Multifunctional nanocomposites with layered structures have shown great promise in supercapacitor (SC) applications due to their unique structures, abundant marginal active sites and diverse electrochemical reaction mechanisms. Using a facile chemical reduction method, a simple and efficient approach has been demonstrated for synthesising iron oxide-silver oxide/reduced graphene oxide (Fe₃O₄-Ag₂O/rGO) nanocomposites. SEM images revealed that Ag₂O/rGO nanocomposites showed noodle-like structure, and as the wt% of Ag grew, the connective network of grains increased from 105 to 190 nm. FETEM results indicated that the inter-planar spacings of 0.35 and 0.56 nm are identified for (331) and (220) crystalline planes of Fe₃O₄, respectively. I_D/I_G and I_T/I_G ratios varied between 0.81 and 1.45 and 0.7 to 6.57 for the Fe₃O₄-Ag₂O/rGO nanocomposites. The bandgap initially increased from 2.16 to 3.5 eV and then decreased from 3.5 to 2.4 eV with the increase in wt% of Ag. The GCD curves showed that the specific capacitance varied from 237.42 to 787 F g^− 1 for the Fe₃O₄-Ag₂O/rGO nanocomposites. The maximum double layer capacitance 2.01 × 10^− 9 F cm^− 2 was observed for (Fe₃O₄)_0.4-(Ag₂O)_0.6/rGO due to the interfacial reaction. The minimum R_ct, E_corr, and I_corr values are 154.72 Ω, 0.017 V and 1.61 µA, respectively, for 80 wt% Ag₂O content of Fe₃O₄-Ag₂O/rGO nanocomposite.