Insight into the Activity and Stability Behaviors of the PbCrO4 Film Photoanode during Solar Water Oxidation in Different Electrolytes

Monoclinic PbCrO₄ is an n-type semiconductor with a band gap of ∼2.2 eV, which has attracted research attentions as photoanode material for solar water splitting in recent years, but few works consider the correlation of PbCrO₄ photoanodes' activity and stability with electrolytes. Herein, typical monoclinic PbCrO₄ films were prepared by a drop-casting method and investigated as photoanodes for solar water splitting in sodium sulfate (NSO), phosphate-buffered saline (PBS), potassium bicarbonate (KHCO), sodium borate (NBO), and potassium hydrogen phthalate (KHP) aqueous electrolyte. The water oxidation activity of the PbCrO₄ film photoanode was found to be closely related to the electrolyte, and a relatively higher activity was observed on the PbCrO₄ photoanode in PBS and KHP. However, in the five types of electrolytes, the PbCrO₄ film photoanode had unsatisfactory stability due to the presence of photocorrosion, composition transformation, and dissolution, posing a significant challenge to the application of PbCrO₄ in solar water splitting. In the Na₂SO₃/KHP mixing electrolyte, improved and stable photocurrent can be achieved on the PbCrO₄ film photoanode for the oxidation of SO₃^2- into SO₄^2-. The present work reveals the objective water splitting behaviors of the PbCrO₄ film photoanode in typical electrolytes, which could provide helpful reference and act as a reminder for the research of PbCrO₄ and similar photoanode materials.