2. Experimental sectionSpinel magne

2. Experimental section
Spinel magnetite nanocrystals were prepared by a sonochemical
method developed in our group [25,26]. Fe3O4 nanoparticles
with size less than 10 nm were used as the core of magnetic photocatalyst. Using the preparation process schematically shown
in Fig. 1, the SiO2 and TiO2 layers were subsequently deposited to
coat magnetite core particles with PAA treatment.