One-Step Hydrothermal Synthesis of Cobalt Sulfide/E-Waste Derived Activated Carbon Nanocomposite as a Bifunctional Electrocatalyst for Overall Water-Splitting

Abstract

An electrocatalyst with high performance can enhance the hydrogen production for overall water-splitting. This study reports on the e-waste-derived activated carbon encapsulated cobalt sulfide (CoS 2 /AC) nanocomposite synthesized via a simple hydrothermal process for overall water-splitting application. The microstructural image of CoS 2 /AC showed the aggregated stacked nanosheets of activated carbon encapsulating the cobalt sulfide nanoparticles. The nanocomposite of CoS 2 /AC exhibited the overpotential of 240 mV at 10 mA cm −2 and a 34 mV dec −1 of Tafel slope value with extraordinary stability for OER. On the other hand, the nanocomposite exhibited the overpotential of 378 mV at 10 mA cm −2 with a Tafel slope of ∼134 mV dec −1 with splendid stability in 1 M KOH solution for HER. The enhanced electrical conductivity and electrochemically active surface area of the AC nanosheets and CoS 2 nanoparticles in this nanocomposite account for its higher electrocatalytic activity. Thus, the hydrothermally synthesized CoS 2 /AC presents itself as a better bifunctional catalyst for overall water-splitting.