Bifunctional layered g-C3N4 incorporated NiSe2 nanocomposites as a highly efficient photocatalyst and electrode material for supercapacitor applications

Problems related to the environment and energy scarcity have attracted considerable interest in the development of materials that can act as photocatalysts and electrode components for energy storage applications. In this study, a nanocomposite comprising NiSe2 and g-C3N4 is prepared using a single-step hydrothermal method. The morphologies, structures, compositions, photocatalytic, and supercapacitor performances of the individual and composite materials are characterized. The photocatalytic degradation efficiency of composite NiSe2/g-C3N4 using RhB dye is 75 % after 200 min, showing an appreciable improvement over the degradation efficiency of pure NiSe2 (57 %). The addition of g-C3N4 into NiSe2 promotes photoinduced electron transfer and provides reaction active sites, which improves the efficiency of the composite. Furthermore, electrochemical measurements of the prepared electrode materials have been studied. The composite delivers a capacitance of 762.64 F g−1 at 5 A g−1 which is nearly six times that of NiSe2 (127.13 F g−1 at 5 A g−1). Moreover, the symmetric supercapacitor cell of the NiSe2/g-C3N4 composite offers 13 Wh kg−1 energy density and a power density of 0.75 kW kg−1. The cell exhibits good cyclic stability with a capacitance retention rate of 71.9 % after 2500 cycles. The synergistic effects of NiSe2 and g-C3N4 are responsible for the superior electrochemical behavior of the composite material. Therefore, the synthesized NiSe2/g-C3N4 composite shows remarkably improved performance in both photocatalytic and supercapacitor applications. [Display omitted] •NiSe2/g-C3N4 is synthesized to study the photocatalytic dye degradation and supercapacitor properties.•NiSe2/g-C3N4 shows an overall 75 % degradation of RhB within 200 min.•NiSe2/g-C3N4 exhibits a specific capacitance of 762.64 F g−1 at 5 A g−1 and a capacity retention up to 89 % after 2300 cycle.•It has an energy density of 21.06 Wh kg−1 and a power density of 1.104 kW kg-1.