Tantalate perovskites are potential candidates for photocatalytic hydrogen production without cocatalyst addition; however, these oxides have large bandgaps, which result in their low photocatalytic activity. In this study, to enhance the photocatalytic activity, CsTaO₃ as a potential photocatalyst and LiTaO₃ as a well-known photocatalyst are subjected to severe plastic strain using the high-pressure torsion (HPT) method. Both superstrained tantalates exhibit optical bandgap narrowing and ∼2.5 times enhancement of photocatalytic hydrogen production. Such bandgap narrowing is mainly due to the formation of oxygen vacancies, although nanocrystal formation and partial amorphization also occur by straining. These findings not only introduce CsTaO₃ as a photocatalyst but also confirm the significance of strain-induced vacancies on the photocatalytic activity of perovskites.

中文翻译：

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应变诱导空位改善钽酸钙钛矿CsTaO ₃和LiTaO ₃的光催化氢逸出

钽酸盐钙钛矿是不添加助催化剂的光催化制氢的潜在候选材料。然而，这些氧化物具有大的带隙，导致其低的光催化活性。在这项研究中，为增强光催化活性，使用高压扭转（HPT）方法对作为潜在光催化剂的CsTaO ₃和作为众所周知的光催化剂的LiTaO ₃进行了严重的塑性应变。两种超应变的钽酸盐都显示出光学带隙变窄，并且光催化产氢量提高了约2.5倍。这种带隙变窄主要是由于氧空位的形成，尽管纳米晶体的形成和部分非晶化也通过应变而发生。这些发现不仅介绍了CsTaO ₃ 作为光催化剂，但也证实了应变诱导的空位对钙钛矿光催化活性的重要性。