Facet-charge-induced coupling dependent interfacial photocharge separation: A case of BiOI/g-C3N4 p-n junction

Heterojunction photocatalyst fabrication benefits the improvement of photocatalytic activity. However, the influence of different coupling facets receives less attention. Herein, two p-n junctions with different coupling facets of BiOI, denoted as B001/CN002 and B110/CN002+, were constructed by a simple precipitation method. In B001/CN002, BiOI nanosheets parallel combined with g-C3N4 with the {001} facet of BiOI and (002) plane of g-C3N4. After being treated by CTAB, the (002) plane of g-C3N4 shows positive charge (g-C3N4+), and the BiOI nanosheets were vertically assembled onto g-C3N4+. The results of photodegradation on multiform industrial contaminants and antibiotic revealed that B001/CN002 shows much higher photoactivity than g-C3N4, g-C3N4+, BiOI and B110/CN002+. The substantially facilitated charge separation and transfer at the interface of B001/CN002 promote the generation of 1O2 and O2−, accounting for the excellent photocatalytic activity. The study may provide a new perspective on designing heterostructured photocatalytic materials via facet-charge-induced interfacial engineering strategy.