Activated porous carbon supported rhenium composites as electrode materials for electrocatalytic and supercapacitor applications

In this study, we developed highly dispersed rhenium nanoparticles decorated on activated carbon (Re@CDACs). The activated carbons were derived from the biomass raw materials cardamom pods (Elettaria cardamomum L) via carbonization followed by activation with ZnCl₂ at high temperature. The Re NPs synthesis was achieved by decomposition of [Re₂(CO)₁₀] complex via a facile microwave thermal reduction technique. The as-prepared Re@CDACs nanocomposites were characterized by a combination of state-of-the-art techniques. The Re@CDACs nanocomposites so prepared were utilized for electrocatalytic oxidation of sunset yellow (SY) and supercapacitor applications. The Re@CDACs electrodes were found to show extraordinary electrochemical performance for sensitive and selective detection of SY with a wide linear range of 0.05–390 μM and a detection limit and sensitivity of 16 nM (S/N = 3) and 91.53 μA μM⁻¹, respectively, surpassing other modified electrodes. Moreover, these Re@CDACs catalysts were also found to exhibit a higher specific capacitance of 181 F g^-1 at a current density of 1.6 A g⁻¹ in 1.0 M H₂SO₄ electrolyte. The specific capacitance retention of 90% was achieved after 2500 cycles at current density 2.0 A g⁻¹. Therefore, we have demonstrated that the Re@CDACs nanocomposite materials could be used as a promising electrode material in electrochemical oxidation of SY and energy storage applications.