Doping and Vacancy Engineering in a Sandwich‐like g‐C3N4/NiCo2O4 Heterostructure for Robust Oxygen Evolution

Abstract

AbstractHerein, N doping and O vacancy were simultaneously introduced into a g‐C3N4/NiCo2O4 heterostructure by a simple reflux and calcination strategy. The constructed g‐C3N4 displayed a porous lamellar structure with N‐doped carbon. Furthermore, numerous ultrathin NiCo2O4 nanosheets with abundant O vacancies tend to grow vertically on the porous g‐C3N4 lamellar, forming a sandwich‐like heterostructure. The prepared sandwich‐like g‐C3N4/NiCo2O4 heterostructure exhibited excellent oxygen evolution reduction (OER) activity with a low overpotential of 294 mV at 10 mA cm−2. Meanwhile, the heterostructure presented superior long‐term stability, retaining a current density of 97.9% after a 50 h chronoamperometry test. The outstanding OER performance is ascribed to the synergistic effect of doping and vacancy engineering in the catalyst, the strong coupling interaction between g‐C3N4 and NiCo2O4, and the porous sandwich‐like structure with abundant active sites. Therefore, the synthetic strategy of g‐C3N4/NiCo2O4 heterostructure can be extended to fabricate high‐performance noble metal‐free electrocatalysts for water splitting.