Interfacial engineering of a vertically stacked graphene/h-BN heterostructure as an efficient electrocatalyst for...

Recently, it was reported that an in-plane graphene (G)/hexagonal boron nitride (h-BN) (G/h-BN) heterostructure provided the catalytic activity for H₂O₂ synthesis by the 2 e^- oxygen reduction reaction (ORR). However, there are few reports on the vertically stacked G/h-BN heterostructure, which refers to the stacking of graphene domains on the surface of h-BN. Herein, a simulated chemical vapor deposition method is proposed for fabricating a heterostructure of abundant vertically stacked G/h-BN by in situ growing graphene quantum dots (GQDs) on porous h-BN sheets. The performance of our vertically stacked heterostructure catalyst is superior to that of reported carbon-based electrocatalysts under an alkaline environment, with an H₂O₂ selectivity of 90-99% in a wide potential range (0.35 V-0.7 V vs. RHE), over 90% faradaic efficiency, and high mass activity of 1167 mmol g_catalyst^-1 h^-1. The experimental results and density functional theory (DFT) simulation verified that the vertically stacked heterostructure exhibits an excellent catalytic performance for the 2 e^- ORR, and the edge B atoms in the B-centered AB stacking model are the most active catalytic sites. This research adequately demonstrates the promising catalytic activity of the vertically stacked G/h-BN heterostructure and provides a facile route for fabricating other vertically stacked heterostructures.