Exfoliated defects-rich g-C3N4 nanosheets heterointerface engineering with CuCo2O4 as promising bifunctional electrocatalysts for seawater splitting

This study synthesizes a novel electrocatalyst based on structural engineering principles to enhance electrochemical performance during water splitting. Exfoliated defect-rich g-C3N4 nanosheets are oriented on copper-cobalt oxide urchin flowers and anchored on nickel foam to synthesize g-C3N4-CuCo2O4/NF. This electrocatalyst exhibits remarkable electrochemical performance for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), with low overpotentials of 315 mV and 268 mV, respectively, at 100 mA cm−2 in 1 M KOH. The synergy of the heterostructure facilitates fast electron transfer and reduces overpotentials. Density functional theory simulations verify that active sites on g-C3N4 facilitate OER and HER. Performances of g-C3N4-CuCo2O4 are compared with those of CuCo2O4 and g-C3N4, and g-C3N4-CuCo2O4 maintains remarkable stability during overall water splitting in electrolytes, including 1 M KOH, 1 M KOH + NaCl, and 1 M KOH + artificial seawater (ASW). Thus, the synthesized g-C3N4-CuCo2O4 has potential applications in fuel cells, CO2 reduction, and lithium batteries.