Influence of Heat Treatment on the Photoelectrochemical Cathodic Protection Performance for SrTiO3 Films

Due to its green and pollution-free characteristics, photoelectrochemical cathodic protection technology is favored by scientific researchers in the research of metal corrosion protection. The conduction band of SrTiO 3 is 0.2 eV more negative than TiO 2 , which has more application potential. The n -type SrTiO 3 films with different heat treatment temperatures were prepared by ultrasonic spray pyrolysis. XRD, SEM, UV–Vis DRS, PL, EIS, Mott–Schottky were used to characterize the phase structure, microscopic morpho-logy, light absorption properties, and carrier properties of the samples. Finally, using 304 stainless steel (304 SS) as the protected substrate, the photoelectrochemical cathodic protection performance of the SrTiO 3 film was investigated. The results show that the SrTiO 3 film heat-treated at 550°C has better light absorption performance, lower photo-generated carrier recombination rate, smaller photo-generated resistance and higher carriers density than samples at 500 and 600°C. The photoelectrochemical cathodic protection performance test results show that: simulated sunlight, the SrTiO 3 film can negatively shift the corrosion potential of 304 stainless steel to –0.34 V in a 3.5 wt % NaCl solution, which is negatively shifted compared to the corrosion potential of 304 stainless steel of –0.18 V up to 160 mV. And four open and closed light cycle tests proved that the performance of the SrTiO 3 film did not decrease.