Ultrathin nanosheet-anchored hexahedral prismatic Bi2MoO6 arrays: one-step constructed and crystal facet-based homojunctions boosting photocatalytic CO2 reduction and N2 fixation

Abstract

A fascinating Bi₂MoO₆ homojunction (HJ) array vertically grown on an FTO substrate was built up through a convenient one-step route; the array consisted of ultrathin nanosheet (NS)-anchored hexahedral prismatic nanorods (NR). HJ exhibited enhanced photocatalytic activities for both CO₂ reduction and N₂ fixation compared to individual NS or NR arrays. The band alignment of the NS unit with the exposed {010} facets and the NR unit with the exposed {100} facets allowed the photo-generated electrons and holes of HJ to migrate to the NR and NS surfaces selectively, effectively achieving spatial charge separation. In addition, the tight connection between NS and NR provided a convenient and fast channel for photogenerated carrier mobility. Meanwhile, the ultrathin thickness of NS enabled the charge carriers to move rapidly from the bulk onto the surface, and the transverse dimension simultaneously rendered a sufficiently spacious transport channel for charge separation. The one-dimensional NR structure also provided special passages for the directional transmission of electrons. This work may provide some insights for designing vigorous crystal facet-based homojunctions for photocatalysis by manipulating interface interactions.