Investigation of the Synergistic Effect of Doping and Composite Formation on Electrochemical OER Performance of g-C3N4 for Sustainable Energy

For sustainable energy generation, the OER half-cell reaction is an important electrochemical process. In this research article, we have successfully synthesized cost-effective pure g-C₃N₄, g-C₃N₄/Cu₂O, and g-C₃N₄/Co-doped Cu₂O composite materials using a simple chemical mixing and annealing approach to investigate their electrocatalytic OER performance. All of the synthesized samples were characterized using XRD, FESEM, TEM, BET, XPS, and UV–visible DRS techniques. XRD analysis revealed successful synthesis of the pure g-C₃N₄ and composite samples, while FESEM and TEM analyses showed successful deposition of a sheet-like g-C₃N₄ sample on Cu₂O and Co-doped Cu₂O samples. The band gap of the composite sample (g-C₃N₄/Co doped Cu₂O) increased to 2.9 eV as compared to pure g-C₃N₄ having a band gap of 2.7 eV. Electrochemical OER activity investigations have shown enhancement in OER current density (18 mA/cm²) in the g-C₃N₄/Co-doped Cu₂O sample compared to the pure g-C₃N₄ sample (current density 0.5 mA/cm²). The enhanced OER activity of the g-C₃N₄/Co-doped Cu₂O sample was attributed to a low Tafel slope (119 mV/dec), confirming the fast reaction kinetics and enhanced charge transfer ability of g-C₃N₄/Co-doped Cu₂O as compared to the pure g-C₃N₄ electrode. Chronoamperometric stability investigation of g-C₃N₄/Co-doped Cu₂O confirms the stable current density for 10 h. Hence, this report shows the synergistic effect of doping and composite formation on electrochemical OER activity.