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

Cu@Cu 2 O films were prepared by electrochemical deposition method. The obtained Cu@Cu 2 O 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@Cu 2 O films. The results indicated that a lower deposition potential could facilitate the reduction of Cu 2 O 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@Cu 2 O-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@Cu 2 O films were discussed in detail.