Graphene/Hexagonal Boron Nitride Heterostructures for O₂ Activation and CO Oxidation: Metal-Free Catalysts by Design

Pristine graphene and <i>h</i>-BN monolayers are chemically inert to oxygen and thus exhibit very limited catalytic activity toward O₂ activation. Herein, we show that graphene/<i>h</i>-BN heterostructures exhibit a surprising O₂ activation capability. We theoretically designed ten graphene/<i>h</i>-BN heterostructures with three types of interfaces and investigated their catalytic activities toward O₂ activation and CO-oxidation. In general, O₂ can be molecularly chemisorbed and activated on electron-rich graphene/<i>h</i>-BN heterostructures. Electron-deficient graphene/<i>h</i>-BN heterostructures can lead to dissociative O₂ adsorption with relatively low dissociation energy barriers (<0.4 eV). For CO-oxidation, the computed energy barrier can be as low as 0.67 eV. The high catalytic activities toward O₂ stem from either electron-deficient heterostructures’ accumulated electrons or electron richness and low work function for the electron-rich heterostructures. Although the catalytic activities of graphene/<i>h</i>-BN heterostructures depend strongly on the interface type, they are insensitive to the patterns of BN-substitutes, hence benefiting applicability of a wide range of heterostructures.