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 [Re-2(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-modified electrodes were found to show extraordinary electrochemical performance for sensitive and selective detection of SY with a wide linear range of 0.05-390 mu M and a detection limit and sensitivity of 16 nM (S/N = 3) and 91.53 mu A mu M-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. (C) 2018 Published by Elsevier Ltd.