Highly Intensified Molecular Oxygen Activation on Bi@Bi₂MoO₆ via a Metallic Bi-Coordinated Facet-Dependent Effect

Construction of the semimetal/semiconductor composite interface is widely used to promote the O2 molecule adsorption and charge transfer for boosting solar-driven molecular oxygen activation (MOA). Herein, a Bi@Bi2MoO6 heterostructure is fabricated via a two-step wet chemical method as a typical photocatalyst to investigate the underlying mechanism of Bi-coordinated facet-dependent MOA under visible-light illumination. Density functional theory and systematical characterization methods reveal the distinct charge transfer and O2 activation processes on the surface of Bi nanoparticle-deposited Bi2MoO6 nanosheets with different facets exposed. By virtue of a particular and efficient [Bi2O2]2+ → Bi → MoO42– interfacial charge-transfer channel, Bi deposited on the (001) facet of Bi2MoO6 can observably intensify MOA, thereby giving birth to more generation of reactive oxygen species and endowing the Bi@Bi2MoO6 with excellent photocatalytic performance in sodium pentachlorophenate (NaPCP) removal. The decomposition pathway of NaPCP is also proposed based on the intermediate determination and mineralization analysis. This work provides deep insights into the mechanism of facet-dependent MOA over a semimetal–semiconductor system and also sheds light on designing effective molecular oxygen-activated interface for environmental remediation.