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

Herein, 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.

Automated summary

N doping and O vacancy were introduced into a g-C3N4/NiCo2O4 heterostructure. The heterostructure exhibited excellent oxygen evolution reduction (OER) activity and long-term stability, showing great potential in water splitting applications.