Influence of deposition potential on the photoelectrochemical cathodic protection behavior of n-type Cu@Cu2O films

Cu@Cu2O films were prepared by electrochemical deposition method. The obtained Cu@Cu2O films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), confocal Raman spectroscopy (CRS), UV–visible absorption spectroscopy and Photoluminescence (PL) spectroscopy. Electrochemical measurements were performed under intermittent visible light illumination to assess the photoelectrochemical cathodic protection effect of the prepared Cu@Cu2O films. The results indicated that a lower deposition potential could facilitate the reduction of Cu2O grain size together with an increase number of Cu. But the deposition potential has no obvious influence on the band-gap of the composite films, which exhibited n-type semiconductor properties. The open circuit potential of 304 stainless steel by coupling with the Cu@Cu2O-0.3 V films presented the most negative shift of −179 mV under visible-light illumination. The related photocurrent density was 0.13 mA·cm−2. The photoelectrochemical conversion mechanism and the photoelectrochemical cathodic protection effects of the Cu@Cu2O films were discussed in detail. In this study, n-type Cu@Cu2O films were prepared on the surface of FTO substrate by electrochemical deposition method. Photoelectrochemical measurements revealed the important role of Cu@Cu2O films on photocathodic protection of 304 SS under visible-light illumination. The open circuit potential of 304 stainless steel by coupling with the Cu@Cu2O-0.3 V films presented the most negative shift of − 179 mV. The related photocurrent density was 0.13 mA·cm−2. The grain size and chemical compositions of the Cu@Cu2O films together with the SPR effect of Cu played an important role on the photoelectrochemical cathodic protection performance. Contribution of this work is to supply a facile method to develop efficient n-type Cu@Cu2O films for photoelectrochemical cathodic protection. Schematic model of the photoelectrochemical cathodic protection behavior of n-type Cu@Cu2O films. [Display omitted] •Contribution of this work is to supply a facile method to develop efficient n-type Cu@Cu2O films for photoelectrochemical cathodic protection.•N-type Cu@Cu2O films property was highly dependent on the electrodeposition potential.•Cu@Cu2O-0.3 V films supplied superior photoelectrochemical cathodic protection.•-The grain size, composition, and SPR effect were crucial to the protection.