Construction of amorphous TiO₂/BiOBr heterojunctions via facets coupling for enhanced photocatalytic activity

Facets coupled BiOBr with amorphous TiO2 composite photocatalysts are synthesized via an in situ direct growth approach under microwave irradiation. XRD, SEM and HRTEM characterizations indicate that the heterointerface between BiOBr and amorphous TiO2 occurs mainly on the {001} facets of BiOBr. BET and TEM verify that the heterojunctions possess higher specific surface areas and smaller amorphous TiO2 particle size than bare BiOBr and amorphous TiO2, exhibiting the inhibition function of BiOBr on the growth of TiO2 particles. XPS verifies the interaction between the two components. The degradation of methyl orange (MO) and phenol are used as the objective reaction to evaluate the photocatalytic activity of the as-prepared samples. The reaction rate constant of 15% TiO2/BiOBr composite is 3.4 times greater than that of pure BiOBr, which is attributed to its higher surface area, and efficient separation of photo-generated electron-hole pairs between BiOBr and amorphous TiO2.