A facile mechanochemical preparation of CoO@g-CN for application in supercapacitors and degradation of pollutants in water.

Our study is aimed at synthesizing cobalt oxide (CoO) with graphite carbon nitride (g-CN) to form a CoO@g-CN hybrid through a green mechanochemical one-pot synthetic approach for manufacturing efficient supercapacitor electrodes and photocatalysts. In the present study, the CoO@g-CN hybrid revealed a significantly higher specific capacitance (C) (of ~ 457.2 Fg at a current density of 1 Ag) than that of the pristine CoO which proved its pseudocapacitive behavior, with a couple of redox peaks observed in three electrode measurements (obtained by using a 3.0-M KOH aqueous electrolyte). The optimized CoO@g-CN hybrid was further embedded for a symmetric supercapacitor performance, delivering an excellent Cs of ~ 92 Fg at a current density of 1 Ag; this was supplemented with a remarkable cycling stability (~ 92% over 5000 cycles). The CoO@g-CN hybrid was further examined for photocatalysis activity using a rhodamine B (RhB) dye, and more than 95% RhB dye was degraded through the photocatalytic reduction process (after 60 min of UV irradiation). This CoO@g-CN hybrid catalyst exhibited excellent reusability and stability and appears to be a highly efficient, cost-effective, eco-friendly, and reusable catalyst; the g-CN present with the CoO acted as a conductive nano-network, leading to a higher capacitive and photocatalytic performance.