Abstract
Titanium dioxide (TiO2) nanotube arrays coupled with a narrow gap semiconductor—bismuth selenide (Bi2Se3)—exhibited remarkable enhancement in the photocathodic protection property for 304 stainless steel under visible light. Bi2Se3/TiO2 nanocomposites were successfully synthesized using a simple two-step method, including an electrochemical anodization method for preparing pure TiO2 and a chemical bath deposition method for synthesizing Bi2Se3 nanoflowers. The morphology and structure of the composite films were studied by scanning electron microscopy, energy dispersion spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. In addition, the influence of the Bi2Se3 content on the photoelectrochemical and photocathodic protection properties of the composite films was also studied. The photocurrent density of the Bi2Se3/TiO2 nanocomposites was significantly higher than that of pure TiO2 under visible light. The sensitizer Bi2Se3 enhanced the efficient separation of the photogenerated electron-hole pairs and the photocathodic protection properties of TiO2. Under visible light illumination, Bi2Se3/TiO2 nanocomposites synthesized by the chemical bath deposition method with Bi3+ (0.5 mmol/L) exhibited the optimal photogenerated cathodic protection performance for 304 stainless steel.
Highlights
As important engineering materials, stainless steels have been widely applied to significant projects in numerous fields due to their excellent corrosion resistance
Characterization of Pure TiO2 and Bi2Se3/TiO2 Figure 2a shows typical top view and cross-sectional topographies for TiO2 films prepared under the anodization method
It is well known that the measurement error of energy-dispersive X-ray spectroscopy (EDS) test is increased with the decrease of content of test element
Summary
Stainless steels have been widely applied to significant projects in numerous fields due to their excellent corrosion resistance. Extensive research and applications of the traditional anti-corrosion method, including coatings [5, 6], use of a sacrificial anode [7] and impressed current cathodic protection [8, 9], have been developed during the past few decades. As a new anti-corrosion technology, photocathodic protection was first proposed by. Titanium dioxide (TiO2) is an important photoelectric material with good photoelectric conversion and photocatalysis properties and is widely used in catalysts [15], solar cells [16] and gas sensors [17] due to its low cost, non-toxicity and stable chemical properties. TiO2 and TiO2-based composites are used for photogenerated cathodic protection: a promising technique for corrosion prevention that has undergone rapid development in recent years [18–23].
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