Controllable construction and efficient photocatalysis performance of Bi@Bi6O7FCl3 heterostructures exposed with the (012) plane bi-quantum-dots

It is imperative to find an environmentally friendly method to design photocatalysts for CO2 reduction. In this work, ultrafine Bi6O7FCl3 nanotubes were synthesized and used as a template to realize the reverse growth of Bi-quantum-dots at the interface of Bi@Bi6O7FCl3-X (X = 20/60/90) nanotube. The facile construction of the (012) plane on Bi quantum dots, with a diameter of approximately 2 nm, was achieved by electron beam irradiation. [Bi6O7]4+ cations and [Cl4]4− anions were first generated through the hydrothermal reaction, and the interaction between the anions and cations resulted in the [Bi6O7Cl4] unit intermediate, in which the negatively charged [Cl4]4− separated the [Bi6O7]4+ layers from each other. In addition, F atoms, with a strong electronegativity, entered the [Cl4]4− layers, replacing a portion of the Cl atoms to form a new [FCl3]4− layer. The binding energy of Bi was reduced by 0.16 eV, as shown by the XPS results. The photocatalytic activity of Bi@Bi6O7FCl3-X (X = 20/60/90) was determined by the production of CO from CO2. After 4 h of monitoring, the CO production rate of Bi@Bi6O7FCl3–90 was 15.79 μmol·g−1·h−1, which was 6.29 times that of Bi6O7FCl3. After 5 cycles, the CO production rate of Bi@Bi6O7FCl3-90 remained at approximately 61.07 μmol·g−1.