The Design of a New Cobalt Sulfide Nanoparticle Implanted Porous Organic Polymer Nanohybrid as a Smart and Durable Water-Splitting Photoelectrocatalyst.

Development of an inexpensive, efficient and robust nanohybrid catalyst as a substitute for platinum in photoelectrocatalytic hydrogen production has been considered intriguing and challenging. In this study, the design and sequential synthesis of a novel cobalt sulfide nanoparticle grafted Porous Organic Polymer nanohybrid (CoS @POP) is reported and used as an active and durable water-splitting photoelectrocatalyst in the hydrogen evolution reaction (HER). The specific textural and relevant chemical properties of as-synthesised nanohybrid materials (Co O @POP &CoS @POP) were investigated by means of XRD, XPS, FTIR, C CP MAS NMR, spectroscopy, HR-TEM, HAADF-STEM with the corresponding elemental mapping, FE-SEM and nitrogen physisorption studies. CoS @POP has been evaluated as a superior photoelectrocatalyst in HER, achieving a current density of 6.43 mA cm at 0 V versus the reversible hydrogen electrode (RHE) in a 0.5 m Na SO electrolyte which outperforms its Co O @POP analogue. It was found that the nanohybrid CoS @POP catalyst exhibited a substantially enhanced catalytic performance of 1.07 μmol min cm , which is considered to be ca. 10 and 1.94 times higher than that of pristine POP and CoS , respectively. Remarkable photoelectrocatalytic activity of CoS @POP compared to Co O @POP toward H evolution could be attributed to intrinsic synergistic effect of CoS and POP, leading to the formation of a unique CoS @POP nanoarchitecture with high porosity, which permits easy diffusion of electrolyte and efficient electron transfer from POP to CoS during hydrogen generation with a tunable bandgap, that straddles between the reduction and oxidation potential of water.