Heterostructure-induced interfacial charge transfer interaction in CoS/CoO@NAC nanosheets as a bi-functional electrocatalyst for water-splitting application.

Recently, bi-functional electrocatalytic materials have the potential for both the hydrogen evaluation reaction (HER) and oxygen evaluation reaction (OER) in the alkaline medium. In the present investigation, the cobalt sulfide/cobalt oxide hanged on the nitrogen-doped activated carbon nanosheets (CoS/CoO@NAC) as nanocomposites were synthesized through the hydrothermal and then the carbonization processes. The X-ray diffraction peaks observed in the CoS/CoO@NAC nanocomposites revealed the presence of CoS, CoO, and N-doped activated carbon nanosheets which confirmed the formation of binary nanocomposites. The BET analysis of CoS/CoO@NAC nanocomposites resulted an enhancement of the surface area of about 1038.57 m2/g along with the pore size and pore volume of 3.23 nm and 0.442 cc/g, respectively. The CoS/CoO@NAC, nanocomposites were used for bi-functional catalysis which divulged the low over potential for both HER and OER analyses at about −0.266 V and 0.199 V vs. RHE, respectively at 10 mA/cm2 current density in the alkaline medium. [Display omitted] • CoS/CoO@NAC nanocomposites synthesized by hydrothermal and carbonization processes. • CoS/CoO@NAC nanocomposites showed an enhancement of surface area of 1038.57 m2/g. • HER analysis of CoS/CoO@NAC shows an overpotential of −0.266 V. • OER analysis of CoS/CoO@NAC shows an overpotential of 0.2654 V. • CoS/CoO/NAC suitable for the bi-functional electrocatalyst in an alkaline medium. [ABSTRACT FROM AUTHOR]