Cobalt diselenide nanotetrapod: An efficient electrocatalyst for hydrogen evolution reaction

Abstract

The science and technology is going through an era where a simple and cost effective synthesis of an earth abundant and efficient electrocatalyst for hydrogen evolution reaction (HER) can provide a key to grand success of hydrogen fuel in practical application. Here, elemental Se mixed CoSe2 nanoparticles that have been synthesized by a simple two-step hydrothermal process own tetrapod-like structures. After important characterizations, CoSe2 nanotetrapod has been utilized as a cathode in the electrochemical HER process. It exhibits low onset potential of − 46 mV and requires almost − 112 mV and − 156 mV to draw current density of 10 and 100 mA/cm2, respectively with Tafel slope of 36 mV/dec. It also pursues low charge transfer resistance with moderate active surface area. The highly hydrophilic CoSe2 nanotetrapod persevere long term stability in acidic medium. Moreover, the high electron density obtained from Mott-Schottky, nanotetrapods with active sites, presence of metallic and conducting Se with electrochemically active CoSe2 and their favorable crystal facets have influenced the HER activity. Thus, the pristine binary CoSe2 can alone beat any previously reported electrochemical catalysts without developing any composites/hybrids or complex compounds.