Facile synthesis of carbon encapsulated RuO2 nanorods for supercapacitor and electrocatalytic hydrogen evolution reaction

In this work, carbon encapsulated RuO2 nanorods (RuO2 NRs/C) has been synthesized by thermolysis of ruthenium chloride and Punica granatum (P. granatum) peel under N2 atmosphere. The synthesized RuO2 NRs/C was characterized using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction method (XRD), field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopy (EDS) analyses. The FT-IR results suggested that the organic constituents of P. granatum have been carbonized and encapsulated over RuO2 nanorods (RuO2 NRs). The XRD pattern of RuO2 NRs/C revealed its crystalline nature and carbon encapsulation. The synthesized RuO2 NRs/C has been well dispersed with the average width of 20 nm, exposed from the FE-SEM and HR-TEM images. The EDS results of RuO2 NRs/C showed the existence of three elements viz., Ru, O and C. Further, the supercapacitor and electrocatalytic hydrogen evolution reaction (HER) activities of RuO2 NRs/C were studied using standard electrochemical methods. The synthesized RuO2 NRs/C offered a maximum specific capacitance of 151.3 F g−1 at a scan rate of 5 mV s−1, obtained from the cyclic voltammetry results. The onset over potential and Tafel slope of synthesized RuO2 NRs/C for HER were −0.099 VRHE and −99.4 mV dec−1, respectively. The present study revealed that RuO2 NRs/C as a better candidate for supercapacitor and HER.