Rong-Gui Du

The corrosion behavior of reinforcing steel in the simulated polluted concrete pore (SPCP) solution and the inhibition effect of a mixture of NaNO₂ and Na₂SiO₃ on the steel corrosion were studied by the scanning microelectrode technique assisted by polarization curve measurements and surface analyses. The results indicated that the steel was active and localized corrosion occurred resulting from the Cl^- attack in the SPCP solution without inhibitors. For the SPCP solution with 0.004 M NaNO₂ and 0.001 M Na₂SiO₃, there were no stable potential peaks on the potential map of the steel immersed in the solution for 8 h, indicating that no localized corrosion took place. Therefore, the mixture of NaNO₂ with Na₂SiO₃ could effectively protect the reinforcing steel from corrosion. The polarization curve measurements and surface analyses also confirmed the above results.

A SnO₂–TiO₂nanotube composite film applied in photoelectrochemical anticorrosion was fabricated by anodic oxidation combined with facile ultrasonic deposition.

TiO₂ nanotube array films were prepared on titanium foils by anodic oxidation in aqueous glycerol solutions with NH₄F. The morphologies and properties of the films prepared in the solutions with different water contents were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis spectroscopy. The photocathodic protection effect of the films were evaluated by measuring the time evolution of the potential of 403 stainless steel coupled to the film photoanodes. The results showed that the TiO₂ nanotube film prepared in the solution with 40 vol% water exhibited excellent photoelectrochemical properties. When the 403 stainless steel in a 0.5 M NaCl solution was coupled to the film under illumination, its potential decreased by 400 mV, showing that the TiO₂ nanotube film provided effective photocathodic protection effect on the steel. Furthermore, the photoelectrochemical performance of the TiO₂ nanotube film could be further improved by a TiCl₄ solution treatment.

A highly ordered TiO₂ nanotube array film was fabricated by an anodic oxidation method. The film was modified by Au nanoparticles (NPs) formed by a deposition–precipitation technique and was covered with a thin ZnS shell prepared by a successive ionic layer adsorption and reaction (SILAR) method. The photoelectrochemical properties of the prepared ZnS/Au/TiO₂ composite film were evaluated by incident photon-to-current conversion efficiency (IPCE), and photopotential and electrochemical impedance spectroscopy (EIS) measurements under white light illumination. The results indicated that the Au NPs could expand the light sensitivity range of the film and suppress the electron–hole recombination, and the ZnS shell could inhibit the leakage of photogenerated electrons from the surface of Au NPs to the ZnS/electrolyte interface. When the 403 stainless steel in a 0.5 M NaCl solution was coupled to the ZnS/Au/TiO₂ nanotube film photoanode under illumination, its potential decreased by 400 mV, showing that the composite film had a better photocathodic protection effect on the steel than that of a pure TiO₂ nanotube film.