Carbon quantum dots decorated NiCo layered double hydroxide for electrochemical oxygen evolution reaction and supercapacitor application

Accelerating depletion of traditional fossil fuel and global warming demand highly efficient, cost-effective, and scalable electrocatalysts for energy conversion processes (water splitting) and energy storage devices (supercapacitor). In this work carbon quantum dot (CQD) decorated NiCo-LDH was successfully prepared on nickel foam as an electrocatalyst for oxygen evolution reaction (OER) and supercapacitor via a facile two-step hydrothermal pathway. Benefiting from improved electrical conductivity with CQD the synthesized CQD/NiCo-LDH showed remarkable electrochemical behavior than NiCo-LDH. The CQD/NiCo-LDH and NiCo-LDH generated a current density of 10 mA/cm² at an overpotential of 226 and 332 mV with Tafel slope of 125 and 147 mV/dec, respectively. In addition, CQD/NiCo-LDH electrodes exhibited specific capacitance of 1136 and 441 F/g at 1 and 10 A/g current density, respectively, and cycling stability of almost 62% specific capacitance retention after 500 charge–discharge cycles.