Although β-Fe₂O₃ has a high theoretical solar-to-hydrogen efficiency because of its narrow band gap, the study of β-Fe₂O₃ photoanodes for water splitting is elusive as a result of their metastable nature. Raman identification of β-Fe₂O₃ is theoretically and experimentally investigated in this study for the first time, thus clarifying the debate about its Raman spectrum in the literature. Phase transformation of β-Fe₂O₃ to α-Fe₂O₃ was found to potentially take place under laser and electron irradiation as well as annealing. Herein, phase transformation of β-Fe₂O₃ to α-Fe₂O₃ was inhibited by introduction of Zr doping, and β-Fe₂O₃ was found to withstand a higher annealing temperature without any phase transformation. The solar water splitting photocurrent of the Zr-doped β-Fe₂O₃ photoanode was increased by 500% compared to that of the pure β-Fe₂O₃ photoanode. Additionally, Zr-doped β-Fe₂O₃ exhibited very good stability during the process of solar water splitting. These results indicate that by improving its thermal stability, metastable β-Fe₂O₃ film is a promising photoanode for solar water splitting.

中文翻译：

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为 β-Fe2O3 在太阳能水分解中的应用铺平道路：拉曼识别、相变和相稳定策略

尽管β-Fe ₂ O ₃由于其窄带隙而具有较高的太阳能到氢的理论效率，但由于其亚稳态性质，β-Fe ₂ O _{3 光}阳极用于水分解的研究难以捉摸。本研究首次对β-Fe ₂ O _{3 的}拉曼鉴定进行了理论和实验研究，从而澄清了文献中对其拉曼光谱的争论。发现β-Fe ₂ O ₃到α-Fe ₂ O _{3 的}相变可能在激光和电子照射以及退火下发生。其中，β-Fe _{2 的}相变O ₃到α-Fe ₂ O ₃被引入Zr掺杂抑制，并且发现β-Fe ₂ O ₃能够承受更高的退火温度而没有任何相变。与纯β-Fe ₂ O _{3 光}阳极相比，Zr掺杂的β-Fe ₂ O _{3 光}阳极的太阳能水分解光电流增加了500% 。此外，Zr掺杂的β-Fe ₂ O ₃在太阳能分解水过程中表现出非常好的稳定性。这些结果表明，通过提高其热稳定性，亚稳态 β-Fe ₂ O ₃ 薄膜是一种很有前途的太阳能分解水光阳极。