Hierarchical nanosheets-assembled nanotubes are of great interest for their unique physicochemical properties as well as their potential applications in a variety of fields. However, the synthesis of hierarchical mixed transition-metal oxides-based nanosheets-assembled nanotubes for highly efficient photocatalytic oxygen evolution is rarely reported. Herein, a simple and versatile approach was developed to synthesize hierarchical nanosheets-constructed MCo₂O₄ (M = Ni, Cu, Zn) nanotubes. Core–shell polyacrylonitrile (PAN)/M-cobalt hydroxide ultrathin nanosheet composite nanofibers were first synthesized by hydroxylation reaction between PAN/M-cobalt acetate hydroxide precursors and NaBH₄. After calcination, these nanofibers as precursors were easily transformed into the corresponding hierarchical nanosheets-constructed MCo₂O₄ nanotubes. By applying a photocatalyst, the resultant MCo₂O₄ nanotubes, particularly the CuCo₂O₄ nanotubes, exhibited high photocatalytic activity and cycle stability toward water oxidation reaction with O₂ generation rates of 51.1 mmol g⁻¹ h⁻¹ under visible light irradiation, which is higher than most reported catalysts. This approach is very versatile and can be applied to synthesize other hierarchical multi-element oxides-based nanosheets-constructed nanotubes for advanced applications.

中文翻译：

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高效合成超薄二维纳米片构成的MCo ₂ O ₄（M = Ni，Cu，Zn）纳米管，以有效地光催化氧气逸出†

分层纳米片组装的纳米管因其独特的物理化学性质及其在各种领域中的潜在应用而备受关注。然而，很少有报道报道了用于高效光催化氧释放的基于分层混合过渡金属氧化物的纳米片组装纳米管的合成。在本文中，开发了一种简单通用的方法来合成分层纳米片构成的MCo ₂ O ₄（M = Ni，Cu，Zn）纳米管。首先通过PAN / M-醋酸钴钴氢氧化物前体与NaBH _4的羟基化反应合成核-壳聚丙烯腈（PAN）/ M-氢氧化钴超薄纳米片复合纳米纤维。。煅烧后，这些纳米纤维作为前体易于转化为相应的分层纳米片构成的MCo ₂ O ₄纳米管。通过施加光催化剂，所得的MCo ₂ O ₄纳米管，特别是CuCo ₂ O ₄纳米管，具有高的光催化活性和对水氧化反应的循环稳定性，O ₂生成速率为51.1 mmol g ^-1 h ^-1在可见光辐射下，比大多数报道的催化剂要高。该方法用途广泛，可用于合成其他分层的，基于多元素氧化物的纳米片构成的纳米管，以进行高级应用。