A novel TiO2 nanotube arrays/MgTixOy multiphase-heterojunction film with high efficiency for photoelectrochemical cathodic protection.

• TiO 2 /MgTi x O y multiphase-heterojunction film was successfully prepared. • SKP is used to measure the surface work function of the photoelectrodes. • TiO 2 /MgTi x O y exhibits significantly enhanced PECCP Performance. • TiO 2 /MgTi x O y shows high PECCP stability. • The mechanism of TiO 2 /MgTi x O y multiphase heterojunctions for PECCP is proposed. Heterojunction engineering, as a rising star in the photoelectrochemical cathodic protection (PECCP) field, contributes to promote the separation of the photoinduced electrons and holes. In this paper, the TiO 2 /MgTi x O y multiphase-heterojunction film was prepared and its PECCP performance was studied. Due to a good energy band alignment gradient formed between the multiphases, the separation efficiency of the photoinduced electrons and holes generated by TiO 2 /MgTi x O y are dramatically enhanced, leading to its good PECCP performance and high stability. SKP is, for the first time, used to study the surface work function of the TiO 2 /MgTi x O y multiphase-heterojunction film for characterizing its PECCP performance. [ABSTRACT FROM AUTHOR]