Construction of atomic-level charge transfer channel in Bi12O17Cl2/MXene heterojunctions for improved visible-light photocatalytic performance

Exploring efficient co-catalysts to accurately steer the charge separation of semiconductor photocatalysts is highly desired yet remains challenging. Here, we tackle the significant challenge by in situ growing the Bi 12 O 17 Cl 2 photocatalyst onto two-dimensional (2D) Cl-terminated Ti 3 C 2 MXene to construct 2D/2D heterojunction of Bi 12 O 17 Cl 2 and Ti 3 C 2 . Firstly, 2D few-layered Ti 3 C 2 MXene with chlorine groups has been successfully synthesized by Lewis acidic etching strategy with subsequent ultrasonic exfoliation. The grafting of chlorine terminations on the surface of MXene serves as nucleating centers and growth platform, resulting in the formation of strong interfacial bonds (Bi–Cl–Ti) between Bi 12 O 17 Cl 2 and Ti 3 C 2 . These strong bonds can facilitate the separation and transfer of photo-generated charge carriers between Bi 12 O 17 Cl 2 photocatalyst and Ti 3 C 2 cocatalyst. As expected, the photocatalytic degradation rate of Bi 12 O 17 Cl 2 /Ti 3 C 2 hybrids is 9.7 times higher than that of bare Bi 12 O 17 Cl 2 nanosheets. This work not only exhibits a new design concept to effectively steer the charge separation for photocatalysis, but also gives a reference for constructing efficient MXene-based photocatalytic systems. Graphical abstract