Construction and Electrochemical Properties of Preferred Crystal Face (002) on Zn Anode Surface

Phosphoric acid etching combined with hydrothermal treatment was used to construct a Sc₂O₃-ZnO coating on the Zn anode surface to tune the content of Zn (002) crystal surface. The (002) crystalline surface of Zn surface became the preferred crystal face for the H₃PO₄ etching time of 7 min and hydrothermal reaction for 2 h at 160°C. The polarization curve results showed that in 2 M of ZnSO₄ solution, the corrosion potential of Zn anode with (002) crystallographically optimal orientation was positively shifted by 663 mV and the corrosion current density was reduced by about four orders of magnitude compared with the bare Zn. The results of LSV and XRD showed that the Zn anode with (002) preferred crystal face possessed a more negative hydrogen evolution potential, which effectively hindered the occurrence of the H₂ evolution side reaction and significantly inhibited the corrosion of metal Zn and the generation of alkaline zinc sulfate hydrate as a byproduct. Dense Sc₂O₃-ZnO coatings composed of crosslinked nanofibers provided a long-lasting and effective shielding protection. The coating facilitated the induction of Zn (002) crystal face oriented deposition, and the bonding of N or P enhanced the stability of coating, which significantly enhanced the corrosion resistance.