Thin layers of ZnO nanoparticles were deposited potentiostaticly on the surface of stainless steel 304 (SS304) at various potentials (−0.7 V, −1.0 V, −1.3 V, −1.6 V) to study the effect of photo-generated cathodic protection on the substrate. Electrochemical methods of open circuit potential (OCP), potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were employed to investigate the electrochemical behaviors of ZnO-covered SS304 system (ZnO/SS304) in 3.5 wt% NaCl solution under the conditions with and without UV illumination. It is found that the ZnO nanoparticles deposited at −1.0 V was in the shape of hexagonal nanorods, which caused a negative shift to lowest OCP upon UV illumination. Polarization curves were also performed on ZnO/ITO glass system to reveal the photoelectrochemical behavior of ZnO nanoparticles only. Possible anodic and cathodic reactions on the ZnO/SS304 and ZnO/ITO systems at the absence and presence of light illumination have been analysed and discussed in detail. It is found that traditional Tafel extrapolation of the polarization curves cannot be used to get the free corrosion current density of ZnO/SS304 system under light illumination due to the superposition of photo-generated current density. The charge transfer resistance obtained from EIS also includes the influence from the photo-generated reactions on the ZnO/SS304 system. Long-term immersion of the ZnO/SS304 in NaCl solution indicates that the ZnO nanorods underwent morphological transitions to nanotubes at 5 days and finally to needles and thin plates at 10 days. Correspondingly, the photocathodic protection of the ZnO layer decreases with the extension of immersion time. The transformation in morphology is postulated to be caused by the attack of Cl⁻ ions on the surface of ZnO nanoparticles.

ZnO纳米粒子薄层以各种电位（-0.7 V，-1.0 V，-1.3 V，-1.6 V）恒电位沉积在不锈钢304（SS304）的表面上，以研究光生阴极保护对阳极氧化的影响。基质。采用开路电势（OCP），电势极化曲线和电化学阻抗谱（EIS）的电化学方法研究了在有或无条件下ZnO覆盖的SS304体系（ZnO / SS304）在3.5 wt％NaCl溶液中的电化学行为。紫外线照明。发现在-1.0V下沉积的ZnO纳米颗粒为六边形纳米棒的形状，其在UV照射下引起负移向最低OCP。还对ZnO / ITO玻璃系统执行了极化曲线，以揭示仅ZnO纳米粒子的光电化学行为。分析和讨论了在不存在和存在光照的情况下ZnO / SS304和ZnO / ITO系统上可能发生的阳极和阴极反应。研究发现，由于光生电流密度的叠加，传统的极化曲线的Tafel外推法不能用于获得ZnO / SS304体系在光照射下的自由腐蚀电流密度。从EIS获得的电荷转移电阻还包括光生反应对ZnO / SS304系统的影响。将ZnO / SS304长期浸泡在NaCl溶液中表明ZnO纳米棒在5天时发生形态转变，转变为纳米管，最后在10天时转变为针状和薄板形式。相应地，ZnO层的光阴极保护随着浸没时间的延长而降低。形态上的转变被认为是由Cl的侵蚀引起的^- ZnO纳米颗粒的表面上的离子。