In-situ fabrication of novel BiOCl/Bi5O7I 2D/3D heterostructures with enhanced photocatalytic activity

•A novel BiOCl/Bi5O7I 2D/3D heterostructure was constructed by in-situ growth method.•The composite exhibited enhanced photocatalytic efficiency for degradation of RhB.•The 2D/3D heterostructure can offer a larger specific surface area and enhanced light absorption capacity.•Type Ⅱ heterojunction of composite can reduce the recombination of photogenerated carriers.