The loading of a cocatalyst is an important strategy for developing efficient and stable photoanodes. CdS/ZnO nanoheterojunction arrays (NHAs) are not suitable for full solar water splitting due to the easy photocorrosion of CdS if there is no sacrificial agent. Herein, CoPi was loaded onto CdS/ZnO NHAs to improve the PEC current and stability. Heat treatment had a critical effect on the PEC performance of the Co-Pi-loaded NHA. The higher crystallinity of the CdS layer with CdCl₂-assisted treatment affords the largest stable current (2.5 mA cm⁻²) for 3 h without performance degradation in 0.1 M phosphate solution (pH = 14). According to the measured band/electrolyte level alignment, the smaller current for full water splitting compared to that in the sacrificial solution is attributed to the large hole transfer resistance owing to the lowered conduction band with CoPi loading. The decrease in photocurrent over 3 h was demonstrated to be due to the photocorrosion of CdS and then the chemical corrosion of ZnO by the phosphate solution. The results suggest that the PEC performance is expected to be improved by optimizing the cocatalyst and the electrolyte solution.

中文翻译：

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用于太阳能完全水分解的CdS / ZnO纳米异质结阵列的结构调制及其相关降解机理†

助催化剂的负载是开发有效和稳定的光阳极的重要策略。CdS / ZnO纳米异质结阵列（NHA）不适合用于完全太阳能水分解，因为如果没有牺牲剂，则CdS容易发生光腐蚀。此处，将CoPi加载到CdS / ZnO NHA上以提高PEC电流和稳定性。热处理对装有Co-Pi的NHA的PEC性能具有至关重要的影响。使用CdCl ₂辅助处理的CdS层具有更高的结晶度，可提供最大的稳定电流（2.5 mA cm ^-2）处理3小时，而在0.1 M磷酸盐溶液（pH = 14）中不会降低性能。根据测得的能带/电解质能级比对，与牺牲溶液相比，用于全水分解的电流较小，这归因于较大的空穴传输阻力，这是由于CoPi负载降低了导带。事实证明，在3小时内光电流的减少是由于CdS的光腐蚀，然后是磷酸盐溶液对ZnO的化学腐蚀。结果表明，期望通过优化助催化剂和电解质溶液来改善PEC性能。