Doping and Vacancy Engineering in a Sandwich‐like g‐C<sub>3</sub>N<sub>4</sub>/NiCo<sub>2</sub>O<sub>4</sub> Heterostructure for Robust Oxygen Evolution
Xiaojun Zeng, Qingqing Zhang, Zong‐Yang Shen, Haiqi Zhang, Tao Wang, Zhenyuan Liu
Abstract
Abstract Herein, N doping and O vacancy were simultaneously introduced into a g‐C 3 N 4 /NiCo 2 O 4 heterostructure by a simple reflux and calcination strategy. The constructed g‐C 3 N 4 displayed a porous lamellar structure with N‐doped carbon. Furthermore, numerous ultrathin NiCo 2 O 4 nanosheets with abundant O vacancies tend to grow vertically on the porous g‐C 3 N 4 lamellar, forming a sandwich‐like heterostructure. The prepared sandwich‐like g‐C 3 N 4 /NiCo 2 O 4 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‐C 3 N 4 and NiCo 2 O 4 , and the porous sandwich‐like structure with abundant active sites. Therefore, the synthetic strategy of g‐C 3 N 4 /NiCo 2 O 4 heterostructure can be extended to fabricate high‐performance noble metal‐free electrocatalysts for water splitting.