Co_xN修饰的Ta₂N/Ta₃N₅纳米叶制备及可见光解水析氢性能

Preparation of Co_xN Modified Ta₂N/Ta₃N₅ Nanosheets and Its Visible Light Photoactivity for Splitting Water into Hydrogen

摘要: 本文利用高温氮化技术，以Ta₂O₅@Ta₃N₅为前驱体，以Co³⁺为修饰剂，成功制备了Co_xN (Co_5.47N, Co₂N)表面修饰的Ta₂N/Ta₃N₅纳米叶，其可见光催化解水产氢活性高达59.2 umolg⁻¹∙h⁻¹，远高于Ta₂O₅@Ta₃N₅前驱体的21.75 umolg⁻¹∙h⁻¹。控制氮化时间调控多重异质结构的组成、电子结构、载流子界面分离和转移。构建Co_xN/Ta₂N/Ta₃N₅多重异质结显著促进了电荷载流子的分离和迁移；缺氮化物Co_5.47N产生等离子共振效应、低价Ta₂N中离域的Ta 5d及N^3-缺陷引入的杂质能级共同作用增强样品的可见光吸收，进而提升样品的光催化水解析氢性能。构建多重异质结为设计开发高效稳定的用于太阳能解水制氢的Ta₃N₅基光催化剂提供新途径。

Abstract: Co_xN (Co_5.47N, Co₂N) surface-modified Ta₂N/Ta₃N₅ nanosheets were prepared by high-temperature nitridation technique, using Ta₂O₅@Ta₃N₅ as precursor, and Co³⁺ as modifier, which shows an ex-cellent visible light photoactivity for splitting water into hydrogen (59.2 umolg⁻¹∙h⁻¹), much higher than that of Ta₂O₅@Ta₃N₅ (21.75 umolg⁻¹∙h⁻¹). The composition, electronic structure, and charge carrier separation and transfer properties of the multi-heterostructures were modulated toward better photocatalytic performance by optimizing nitridation time. Construction of Co_xN/Ta₂N/Ta₃N₅ multiple heterojunctions significantly promotes the separation and migration of charge carriers. Subnitride Co_5.47N producing a plasma resonance effect, and sub-bandgap behavior from delocalized Ta 5d of reduced Ta species and anion defect N-vacancies improved visible light absorption. Furthermore, the photocatalytic water analysis of hydrogen performance of the sample was im-proved. Constructing multi-heterostructures provides a promising avenue to design efficient and stable Ta₃N₅-based photocatalysts for solar water splitting.