Efficient Charges Separation Using Advanced BiOI-Based Hollow Spheres Decorated with Palladium and Manganese Dioxide Nanoparticles

Multishell hollow structures have attracted tremendous attention due to their outstanding properties for application on photocatalysis. In this work, we demonstrated a straightforward and general method to construct BiOI-based core-double shell hollow spheres for the first time. The core-double shell hollow spheres consist of Pd particles and MnO x loaded onto the inner and outer surfaces of BiOI hollow spheres, respectively (Pd/BiOI/MnO x ), and utilized them as an advanced photocatalyst for photocatalytic oxidation of formaldehyde gases and methyl blue. The hollow spheres structure could provide a large specific surface area, exposing a large number of catalytic active sites. Additionally, the Pd particles and MnOx serve the function of separating the reduction and oxidation reactive sites. The unique morphology combined with enhanced light-absorption provided the Pd/BiOI/MnO x core-double shell hollow spheres with high efficiency for the photocatalytic oxidation of formaldehyde gases and methyl blue. In situ diffuse reflectance infrared Fourier transform and electron spin resonance measurement were performed to study the mechanism of photocatalytic degradation, which revealed the important role of h + and · O 2 – during the photocatalytic reaction. These findings shed some light on the design of highly efficient photocatalysts for environmental protection.