Electrochemical aspects of Co3O4 nanorods supported on the cerium doped porous graphitic carbon nitride nanosheets as an efficient supercapacitor electrode and oxygen reduction reaction electrocatalyst

Abstract

Herein, the electrochemical performance of Ce-PGCN,NS/Co3O4 as a metal-free ORR electrocatalyst and supercapacitor electrode was investigated. FESEM, TEM, BET, FTIR, XRD, EDX, FTIR, and Raman tests were used to characterize the synthesized electrocatalysts. For ORR measurements, voltammetry (CV, LSV, Choronoamperometry) and EIS tests were used to investigate the electrocatalytic activity of the electrocatalysts. And for supercapacitor measurements, the CV and GCD tests were conducted to examine the electrode's capacitance. The results of the voltammetry tests show that Ce-PGCN,NS/Co3O4 with an onset potential of −0.027 V, selecting four-electron pathway (n = 3.86), Tafel slope of 137 mV/dec, charge transfer of 570 Ω, and high durability in alkaline media (0.1 M KOH) show an excellent electrochemical performance as an ORR electrocatalyst and can be introduced as a promising substitution for commercial Pt/C catalysts. On the other hand, the results of CV in supercapacitor mode and GCD reveal that Ce-PGCN,NS/Co3O4 electrode with the specific capacitance of 789 F g−1 at the current density of 1 A g−1 and high stability in alkaline media (2 M KOH), have superior performance as a supercapacitor electrode than other electrode based on the g-C3N4. Also, it is observed that converting bulk g-C3N4 to PGCN,NS, doping Cerium atoms on the structure of the PGCN,NS, and adding Co3O4 nanorods impact the electrocatalytic activity of g-C3N4 positively.