Controlled synthesis of efficient novel Cr0.2Co2.8O4–MoO3 nanocomposites for high-performance O2-evolution and methanol oxidation in alkaline medium

Abstract

The world of electrochemical devices is constantly pushing the boundaries to what's possible, and nanocomposites are becoming crucial electrocatalysts for enhancing electrochemical performance. In this study, the affect in electrochemical behaviour on altering constituent amount in the electrocatalysts has been discussed. For this we synthesized a novel Cr0.2Co2.8O4–MoO3 nanocomposites with varying constituent proportional amount using simple low-temperature route. The formation and the physicochemical properties have been investigated by Fourier-transform infrared spectroscopy (FTIR), X-Ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), Raman, Scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDS) and Brunauer-Emmett-Teller (BET) techniques. The XRD and XPS patterns confirms the nano crystalline structures and compositional difference in metal cations distribution respectively. Results from Cyclic Voltammetry (CV), Tafel experiments, Chronoamperometry and Electrochemical impedance Spectroscopy (EIS) shows the ratio of Cr0.2Co2.8O4 to MoO3 strongly affects the catalytic performance in both oxygen evolution and methanol oxidation reactions. The observed enhancement in electrocatalytic activity can be ascribed to the combined impact of the two materials facilitating the electron transfer process by increasing the number of active sites and thereby. Amongst different synthesized electrocatalysts the one with 1:4 composition exhibited not only the highest Specific activity of 2.5 × 103 mA cm−2/g at 700 mV towards OER but also retains maximum current showing their highest stability.