光電化學水分解技術對於解決現今能源短缺及環境污染的議題具有極大的潛力，如何製備出具有高效能的光電極是使此技術獲得突破的關鍵。α-Fe₂O₃ 因其適中的能隙及較好的化學穩定性，被視為極具發展潛力的光陽極材料。然而，其極短的載子擴散距離與嚴重的表面電荷複合現象，嚴重限制了其光電化學性能。為解決此困境，本研究利用水熱法於 FTO 導電玻璃上製備α-Fe₂O₃ 奈米柱與 Bi₂O₂S 奈米片，成功建構出複合結構，藉此有效促進光生載子的快速分離。本研究透過拉曼光譜、XPS、SEM、XRD 及 UV-vis 等技術進行詳盡的表面材料特徵分析。
光電化學 (PEC) 量測結果顯示，最佳化比例之 Fe₂O₃/Bi₂O₂S 複合光陽極 (FRBS 1/10.7) 展現出優異的效能提升。在 0.5 M NaOH 電解液與標準光照下，其最高光電流密度可達約 0.25 mA/cm²，相較於純 Fe₂O₃ 提升了約十倍。電化學阻抗頻譜 (EIS) 亦證實，此異質結構能大幅降低界面電荷轉移阻抗 (Rct) 至約 2200 Ω，且外加偏壓光電轉換效率 (ABPE) 提升至 0.21%。
在長時間的穩定性測試與反應後 XPS 分析中進一步發現，表層 Bi₂O₂S 在 PEC 反應過程中可能發生硫流失、氧化或部分溶解，並殘留少量 Bi–O 表面物種。這些 Bi–O 物種並非主要載子傳輸通道，而可能在反應初期改變 Fe₂O₃ 與電解液之接觸方式，進而降低 Fe₂O₃ 發生全面且劇烈重構的程度。最終，FRBS 樣品較佳的長時間光電流穩定性，主要可歸因於底部 Fe₂O₃ 奈米柱骨架的保留，以及表面形成較受控制之 Fe₂O₃/FeOOH 重構界面。

Photoelectrochemical water splitting is a promising approach for addressing energy shortages and environmental pollution, and the development of efficient photoelectrodes is essential for improving its performance. Although α-Fe₂O₃ is considered a promising photoanode material because of its suitable band gap and chemical stability, its performance is limited by its short carrier diffusion length and severe surface charge recombination.
In this study, α-Fe₂O₃ nanorods and Bi₂O₂S nanosheets were hydrothermally synthesized on FTO substrates to form composite photoanodes. Raman spectroscopy, XPS, SEM, XRD, and UV–vis spectroscopy were used for material characterization. The optimized FRBS 1/10.7 sample achieved a maximum photocurrent density of approximately 0.25 mA cm⁻² in 0.5 M NaOH, approximately ten times higher than that of pristine Fe₂O₃. Its charge-transfer resistance was reduced to approximately 2200 Ω, while the ABPE increased to 0.21%.
Stability tests and post-reaction XPS analyses indicated that Bi₂O₂S underwent sulfur loss, oxidation, or partial dissolution during PEC operation. The improved long-term stability was mainly attributed to the preservation of the Fe₂O₃ nanorod framework and the formation of a more controlled Fe₂O₃/FeOOH reconstructed interface.

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