Unusual redox activity of composite alkaline earth metal oxides and reduced graphene oxide system

Abstract

Reduced Graphene Oxide (rGO) impregnated on alkaline earth oxides (Group 2) (CaO, SrO, BaO) matrix following mechanical mixing, thermal annealing and subsequent cold shock has synthesized a new electrochemical material. The characterization has been carried out by Fourier Transformation Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM) and Powder X-Ray Diffraction (PXRD) measurements in µm dimension. Thermal stability has been checked by Thermal Gravimetric Analysis and Differential Scanning Calorimetry (TGA-DSC). Cyclic Voltammetry (CV) of the composites show anodic peak potential (E_pa) order rGO-CaO (-0.6 V) < rGO-SrO (-0.4 V) < rGO-BaO (-0.3 V) which also follows ordering of ionic size, Ca²⁺ (100 pm) < Sr²⁺ (118 pm) < Ba²⁺ (135 pm). This character becomes more prominent as we move down the Group 2. Thermal stability of these coupled systems also increases down the group.