Hollow nanoparticles doped hierarchical hexagonal star shaped cobalt-based phosphosulfides for water splitting

Hollow nanoparticles doped hierarchical hexagonal star shaped cobalt (Co) phosphosulfides (CoS/P) have been prepared with sulphidation and phosphorization of Co-based hydroxides as precursors sequentially. Each corner of a hexagonal star is composed of many branched nanorods. Hollow nanoparticles with an average size of 50 nm are observed on these branches. The resulting CoS/P catalyst shows efficient water splitting activity. These hollow nanoparticles provide more exposed active sites with enhanced reaction activity and reaction rate. The CoS/P could serve as a bifunctional OER and HER catalyst with an overpotential of 320 mV and 210 mV, respectively, at j = 10 mA cm ⁻². The CoS/P exhibited an overpotential of 470 mV for overall water splitting at j = 10 mA cm ⁻² . Theoretical calculations also confirm the beneficial effect of CoS/P compared with CoS. This novel hierarchical structure is a promising electrocatalyst for overall water splitting.