Photocatalytic water splitting to generate hydrogen (H₂) is a sustainable approach for solving the current energy crisis. A novel TiO₂/NiS core–shell nanohybrid was fabricated where few-layer NiS nanoplates were deposited on TiO₂ skeletons via electrospinning and hydrothermal methods. The NiS nanoplates with a thickness of ca. 28 nm stood vertically and uniformly upon the TiO₂ nanofibers, guaranteeing intimate contact for charge transfer. XPS analysis and DFT calculation imply that the electrons in NiS would transfer to TiO₂ upon hybridization, which creates a built-in electric field at the interfaces and thus facilitates the separation of useful electron and hole upon photoexcitation. In-situ XPS analysis directly proved that the photoexcited electrons in TiO₂ migrated to NiS under UV–visible light irradiation, suggesting that a direct Z-scheme heterojunction was formed in the NiS/TiO₂ hybrid. This direct Z-scheme mechanism greatly promotes the separation of useful electron–hole pairs and fosters efficient H₂ production. The hybrid nanofibers unveiled a high H₂-production rate of 655 μmol h^–1 g^–1, which was 14.6-fold of pristine TiO₂ nanofibers. Isotope (⁴D₂O) tracer test confirmed that H₂ was produced from water, rather than from any H-containing contaminants. This work provides an alternative approach to rationally design and synthesize TiO₂-based photocatalysts with direct Z-scheme pathways toward high-efficiency photogeneration of H₂.

中文翻译：

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具有增强的光催化H _2的直接Z型TiO ₂ / NiS核-壳杂化纳米纤维-生产活性

光催化水分解产生氢（H ₂）是解决当前能源危机的可持续方法。制备了一种新颖的TiO ₂ / NiS核壳纳米杂化体，其中通过电纺丝和水热方法在TiO ₂骨架上沉积了几层NiS纳米板。NiS纳米板的厚度约为。28 nm垂直且均匀地竖立在TiO ₂纳米纤维上，确保紧密接触以进行电荷转移。XPS分析和DFT计算表明，杂交后NiS中的电子会转移到TiO ₂上，这会在界面处产生内置电场，从而在光激发时促进有用电子和空穴的分离。原位XPS分析直接证明了TiO ₂中的光激发电子在紫外可见光照射下迁移到NiS，这表明在NiS / TiO ₂杂化物中形成了直接的Z型异质结。这种直接的Z方案机制极大地促进了有用的电子-空穴对的分离，并促进了有效的H ₂产生。杂化纳米纤维的高H _2生成速率为655μmolh ^–1 g ^–1，是原始TiO ₂纳米纤维的14.6倍。同位素（⁴ D ₂ O）示踪剂测试证实了H ₂是由水而不是由任何含H的污染物产生的。这项工作提供了一种替代方法，可以合理设计和合成具有直接Z方案途径的TiO ₂基光催化剂，从而实现H ₂的高效光生。