Construct 2D/1D BiOX (X = Cl, Br)@Bi5O7I heterojunctions with rich interfaces and wide visible light response range for pollutant removal in water under LED light

At present, the development of photocatalysts with high visible light sensitivity and efficient catalytic activity for environmental pollution control is the focus of research in the field of photocatalysis. In this work, 2D/1D BiOX (X = Cl, Br)@Bi5O7I heterojunction with abundant interfaces was prepared by a low-temperature liquid-phase method using Bi5O7I nanorods as substrate and BiOX nanoflakes as shell. The rich interfaces can be used as transport bridge for photogenerated electrons between Bi5O7I and BiOX. Under the optimum condition of BiOX content of 60%, the surface charge transfer efficiency increased from 20.79% (Bi5O7I) to 55.44% (BOI-BC-60) and 67.36% (BOI-BC-60) according to the photoelectrochemical measurement results. In the application of photocatalytic degradation of levofloxacin, the prepared BiOX (X = Cl, Br)@Bi5O7I heterojunctions exhibited enhanced adsorption capacity in darkness and improved photocatalytic activity under visible light. The reaction rate and pollutant removal efficiency of BOI-BC-60 and BOI-BB-60 were 6.87, 2.07 and 12.17, 3.28 times higher than that of Bi5O7I, respectively. It is proved that the suitable valence band and conduction band positions of BiOX and Bi5O7I components in BiOX@Bi5O7I heterojunction provide thermodynamic conditions for the migration of photogenerated electrons and holes.