The occurrence of two peaks in the CV scan suggests that electrochemical reactions possibly occur at -1.1 and -1.8 V. To investigate these reactions, the samples were exposed to the fixed voltages of -1.1 and -1.8 V for 15 min. Additionally, another set of samples were prepared at a higher voltage of -2.3 V to observe whether the higher voltage further changes the resulting chemical profile of the samples. The samples are named as Cr2O3/rGO-x V-y min according to the synthesis voltage (x) and time (y).