Urchin-like ternary cobalt phosphosulfide as high-efficiency and stable bifunctional electrocatalyst for overall water splitting

The development of efficient non-noble bifunctional electrocatalysts for the overall water splitting is a pressing and challenging task. In this work, we report a sea urchin-like cobalt phosphosulfide (CoPS) ternary compound for overall water splitting. Because CoPS contains more than one nonmetallic element, ternary compounds possess dianions might lead to modulated electronic structure and thus modified their electrocatalytic properties. Our DFT calculation results reveal that the ternary CoPS exhibits favorable performance for both the oxygen evolution reaction and hydrogen evolution reaction. Experimentally set as cathode and anode in a full cell for overall water splitting, the CoPS cell needs a voltage of only ∼1.59 V to reach a current density of 10 mA cm−2 and has outstanding stability. Our results open up a path to search for alternative bifunctional electrocatalyst materials to substitute for noble metals in overall water splitting.