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-C 3 N 4, g-C 3 N 4 /Cu 2 O, and g-C 3 N 4 /Co-doped Cu 2 O 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-C 3 N 4 and composite samples, while FESEM and TEM analyses showed successful deposition of a sheet-like g-C 3 N 4 sample on Cu 2 O and Co-doped Cu 2 O samples. The band gap of the composite sample (g-C 3 N 4 /Co doped Cu 2 O) increased to 2.9 eV as compared to pure g-C 3 N 4 having a band gap of 2.7 eV. Electrochemical OER activity investigations have shown enhancement in OER current density (18 mA/cm 2 ) in the g-C 3 N 4 /Co-doped Cu 2 O sample compared to the pure g-C 3 N 4 sample (current density 0.5 mA/cm 2 ). The enhanced OER activity of the g-C 3 N 4 /Co-doped Cu 2 O sample was attributed to a low Tafel slope (119 mV/dec), confirming the fast reaction kinetics and enhanced charge transfer ability of g-C 3 N 4 /Co-doped Cu 2 O as compared to the pure g-C 3 N 4 electrode. Chronoamperometric stability investigation of g-C 3 N 4 /Co-doped Cu 2 O confirms the stable current density for 10 h. Hence, this report shows the synergistic effect of doping and composite formation on electrochemical OER activity.