Preparation and Photocathodic Protection Properties of ZnO/TiO2 Heterojunction Film Under Simulated Solar Light

Abstract

In this work, a novel double layer made of ZnO nanorod arrays and TiO2 nanorod arrays with anticorrosion function were successfully prepared on fluorine-doped tin oxide (FTO) substrate by a simple low-temperature solvothermal method. As compared with the pure TiO2 and pure ZnO film, the combination of the two films presented higher photocathodic protection performance for 316 stainless steel (316 SS) and Q235 carbon steel in 3.5 wt% NaCl solution. The composite film with ZnO nanoparticles layer between ZnO nanorod arrays and TiO2 nanorod arrays exhibited the best photocathodic performance, which lowered the open circuit potential (OCP) of 316 SS and Q235 to −991 mV, −1066 mV, respectively. The results demonstrated that the formation of the uniform heterojunction film and the small difference in band alignment played important roles in the promotion of photocathodic protection performance.

Review of TiO2-Based Heterojunction Coatings in Photocathodic Protection

“…The solvothermal method, which employs an organic solvent instead of water, can also be employed to prepare high-purity heterojunction coatings with controlled particle size and morphology. , Guo et al produced NH 2 -MIL-125/TiO 2 heterojunction coatings through a solvothermal reaction at 150 °C for 20 h. 2-Aminoterephthalic acid was used as the raw material, and N , N -dimethylformamide and methanol were used as solvents (Figure C). TEM images demonstrated that a regular platelike NH 2 -MIL-125 was loaded onto the TiO 2 surface, with particle sizes ranging from 300 to 820 nm (Figure D).…”

A novel CaIn2S4/TiO2 NTAs heterojunction photoanode for highly efficient photocathodic protection performance of 316 SS under visible light

“…Furthermore, its high photogenerated carrier recombination rate diminishes its protection effect for metals in the dark state [18]. One of the most effective ways to overcome the above shortcomings is constructing heterojunction composites with other semiconductors that have narrow band gaps (such as BiVO 4 [19], WO 3 [20], ZnO [21] and ZnPc [22]).…”