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The global annual consumption of marine metal corrosion is a significant challenge to the service life of metals and the development of marine strategies. A tri-dimensional AgInS2/In2S3 co-modified TiO2 nanobush (NB) superstructure photoanode is constructed. It shows superior photoelectric cathodic protection (PECP) characteristic for pure copper whose self-corrosion potential is more negative in simulated natural marine environment without additional any hole scavengers under simulated solar light illumination. Origin from the more negative energy level potential of AgInS2/In2S3, the quasi-Fermi level of the photogenerated electrons of TiO2 NB/AgInS2/In2S3 was pull to a more negative position, reinforcing the transmission of photogenerated electrons to the pure copper whose self-corrosion potential is more negative. The sensitizer AgInS2 together with the assistant layer In2S3 dramatically enhances the PECP performance of TiO2 NB/AgInS2/In2S3. The tri-dimensional ultrafine branch-like architecture of TiO2 NB with the nanoparticles quickens the collection and transfer of photogenerated electrons to the metallic pure copper. This environmentally friendly 3D photoanode structure provides a good reference for the optimized construction of photoelectric materials for marine metal corrosion protection. The tri-dimensional AgInS2/In2S3 co-modified TiO2 nanobush superstructure photoanode possesses superior photoelectric cathodic protection characteristic for pure cooper whose self-corrosion potential is more negative in simulated marine environment under simulated solar light illumination. [ABSTRACT FROM AUTHOR]

• ZnIn 2 S 4 /TiO 2 nanoflowerbush photoanode was prepared by facile hydrothermal method. • The nanoflower-like ZnIn 2 S 4 was tightly incorporated on ultrafine branched TiO 2 NB. • The heterojunction greatly promotes the transfer of the photogenerated carriers. • ZnIn 2 S 4 /TiO 2 NFB exhibits photoinduced CP performance for metals in NaCl solution. [Display omitted] Boosting the photoinduced cathodic protection (CP) for metals in NaCl solution is crucial for achieving the application of photoelectrochemical conversion in marine corrosion protection. An environmentally friendly three-dimensional ZnIn 2 S 4 /TiO 2 nanoflowerbush (NFB) photoelectrode was constructed with sufficient interfacial incorporation based on the ultrafine branched TiO 2 nanobush substrate via a facile in situ hydrothermal method. This ZnIn 2 S 4 /TiO 2 NFB nanoheterojunction composite behaves excellent photoinduced CP performance for metallic materials. This is owing to the optimized construction of photoelectrode with relatively negative band potential, wide solar spectrum response, effective generation and collection of photoinduced electrons. The morphology, distribution and performance of ZnIn 2 S 4 vary with different substrates. The pure ZnIn 2 S 4 powder is nanoflower sphere composed of a lot of thin petals; when ZnIn 2 S 4 grow onto the FTO glass, the ZnIn 2 S 4 petals are distributed vertically on the two-dimensional structure; when ZnIn 2 S 4 grow on the three-dimensional ultrafine branched TiO 2 nanobush substrate, a ZnIn 2 S 4 /TiO 2 NFB architecture with ultrafine TiO 2 branchlet cores are formed. This ZnIn 2 S 4 /TiO 2 NFB photoelectrode can achieve efficient photoinduced CP performance for pure copper and low alloy steels with different negative self-corrosion potentials, such as Cu (−0.18 V), E40 (−0.45 V), Q345 (−0.55 V) and Q235 carbon steel (−0.65 V) under simulated sunlight irradiation in NaCl solution without additional hole scavengers, and the photoinduced CP current densities reach as high as 170, 72, 63 and 44 μA cm−2, respectively. The high-efficiency photoinduced CP performance is closely related to the band structure gradient matching between the TiO 2 and ZnIn 2 S 4 , prompting both the widened absorption of solar spectrum and high-efficiency transfer of the photogenerated electron–hole pairs. Importantly, the negative band potential of ZnIn 2 S 4 endues a lower surface work function which benefits the electron transport to the under-protected metallic materials to achieve photoinduced CP. This photoelectrode exhibits huge photoinduced CP application potential in marine environments. [ABSTRACT FROM AUTHOR]