Fabrication of heterostructured β-Bi2O3-TiO2 nanotube array composite film for photoelectrochemical cathodic protection applications

•A β-Bi2O3 sensitized TiO2 nanotube film was fabricated.•The β-Bi2O3-TiO2 composite film exhibited a broader light absorption region.•The enhanced photoelectrochemical properties were obtained for the β-Bi2O3-TiO2 film.•The composite film provided effective photocathodic protection for stainless steel.