Preparation of Ag@CuFe2O4@TiO2 nanocomposite films and its performance of photoelectrochemical cathodic protection

Abstract

• Ag@CuFe 2 O 4 @TiO 2 nanocomposite has excellent photochemical cathodic protection performance for 304 stainless steel. • The protective potential of Ag@CuFe 2 O 4 @TiO 2 is 14.8 times that of pure TiO 2 nanowires. • Ag@CuFe 2 O 4 @TiO 2 can also provide cathodic protection for 304 stainless steel in dark conditions. • The heterojunction electric field of Ag@CuFe 2 O 4 @TiO 2 enhances the separation ability of photogenerated electrons and holes. A Ag@CuFe 2 O 4 @TiO 2 nanocomposite film with high performance of photogenerated cathodic protection was prepared by hydrothermal and photoreduction methods. The results showed that when the CuFe 2 O 4 hydrothermal reaction time was 6 h and the AgNO 3 concentration was 0.1 M, the Ag@CuFe 2 O 4 @TiO 2 nanocomposite material performed the best cathodic protection capability for 304 stainless steel (304SS). In this case, the protective potential achieved −930 mV (versus SCE) associated with the photocurrent density of 475 μA/cm 2 , which was 14.8 times that of pure TiO 2 nanowires. In the dark, the nanocomposite provided cathodic protection of up to 485 mV for 304SS. Due to the heterogeneous junctions at the two interfaces among the three kinds of nanocomposite materials, the build-in electric field was fabricated, which promoted the separation efficiency of photogenerated electrons and holes and effectively improved the photochemical cathodic protection of 304SS. Proposed mechanism for the enhanced photoelectric activity of Ag@CuFe 2 O 4 @TiO 2 nanocomposite for photoelectric cathodic protection on 304SS under visible light illumination.