Graphical Photocathodic protection is promising to harvest solar light for corrosion protection of metals. Benefiting from a considerably enhanced absorption for visible light and a significantly increased transfer efficiency for photogenerated charges, the as-prepared ZnO/ZnSe/CdSe photoanode exhibits a superior photocathodic protection performance for the coupled 304 stainless steel under illumination. Photocathodic protection technology is emerging to harvest solar light for electrochemical corrosion protection of metals. Herein, ZnO/ZnSe/CdSe heterostructured nanowire arrays were synthesized on conductive glass substrates by a two-step ion-exchange reaction in ZnO nanowire arrays. The as-prepared ZnO/ZnSe/CdSe core/shell nanostructure was unveiled by XRD, SEM, TEM, EDAX elemental mapping, and XPS analyses. The ZnO/ZnSe/CdSe ternary heterojunction photoanode exhibits a considerably enhanced absorption for visible light and a significantly increased separation, transfer, and collection efficiencies for photogenerated charges. When working as photoanodes, the as-deigned ZnO/ZnSe/CdSe heterostructured nanowire arrays demonstrates a superior photocathodic protection performance for the coupled 304 stainless steel under illumination with AM 1.5G.
Quaternary semiconductor film consists of ZnO, ZnSe, CdSe and MoS 2 was designed to establish a core-shell structure to achieve the photoelectrochemical oxidation of amoxicillin . The hybrid photoelectrode was fabricated on a FTO substrate from bath deposition methods . The hierarchical ZnSe/CdSe/MoS 2 shell was covered uniformly on ZnO nanorod core which provided a direct pathway for electron transfer , large surface area to enhance light absorption and increase active sites. The quaternary photoelectrode exhibited a photocurrent density of 26.86 mA/cm 2 at 0 V vs. Ag/AgCl under UV–visible light illumination, which was 31.9 times, 16.7 times and 1.6 times of that of the bare ZnO nanorods, binary ZnO/ZnSe and ternary ZnO/ZnSe/CdSe photoelectrodes, respectively. 10 ppm of amoxicillin was completely degraded in 30 min by the quaternary working electrode with an applied bias of 0.5 V vs. Ag/AgCl. The reusability and stability of quaternary electrode was demonstrated by 3-run recycling experiments. The enhanced photoelectrochemical performance of quaternary photoelectrode can be attributed to the enhancement of light absorption and increased active sites from the coverage of visible-active layers, the accelerated charge separation from the formation of p-n junction and reduced photocorrosion of CdSe from the protection of MoS 2 on the surface.
The erosion issue of ZnO nanorod arrays (NRAs) film is the major obstacle in surface sensitization of ZnO NRAs grown on Zn foil substrate for photoelectrochemical (PEC) applications. In this paper, PEC performance of ZnO NRAs grown on Zn foil substrate was greatly enhanced by coating ZnSe and CdSe on the surface of ZnO NRAs. Dense ZnO NRAs were in - situ grown on seed-free Zn foil substrate in a NH 3 ·H 2 O and NaOH hydrothermal system. ZnSe/CdSe co-sensitized ZnO heterostructures were then successfully synthesized using ZnO NRAs as precursors by two successive in - situ ion exchanges without damaging Zn foil and ZnO NRAs film. To obtain optimal photoconversion efficiency, anion exchange time and temperature were optimized. ZnO/ZnSe/CdSe heterostructures with optimized structure were shown as a layer of compact ZnSe/CdSe nanofilm conformally and uniformly coated on ZnO NRAs, which leads to efficient separation of photogenerated carriers , significant enhancement in visible-light absorption, and excellent PEC performance with photocurrent density of 3.008 mA/cm 2 (−0.2 V vs . Ag/AgCl) and photoconversion efficiency of 1.99% (0.418 V vs . RHE in polysulfide electrolyte solution), 27.55 and 40.61 times higher than those of ZnO NRAs, respectively.