The advancement of photoelectrochemical water splitting oxygen evolution technology is the key to improving the solar-hydrogen conversion efficiency. The theoretically highly active hematite-based photoanode still requires modification from inside to outside to conquer ultrafast carrier recombination and a high reaction barrier. Herein, we report a uniform and ultrathin cocatalyst with coordinated tannic acid, Ni, Fe, and Co (TA–NFC), for enhancing photoelectrochemical performance of the F-doped Fe₂O₃ nanorod (NR) photoanode. The F-doping in the structure fulfills more carrier density and lower charge transfer resistance for accelerating photogenerated electron and hole separation. Furthermore, the TA–NFC cocatalyst on the surface assists hole injection and supports faster water oxidation kinetic. Ultimately, the photocurrent density of F–Fe₂O₃@TA–NFC NRs sharply increased up to 3.02 mA/cm² at 1.23 V versus RHE, and the applied-bias photon-to-current efficiency reached 0.33% maximum at low bias. This work may supply a novel and promising design scheme for improving the intrinsic photoelectrochemical activity of semiconductor-based photoanodes.

中文翻译：

---

用配位单宁酸和三元金属装饰助催化剂膜以提高掺氟赤铁矿光阳极的光电化学性能

光电化学水分解析氧技术的进步是提高太阳能-氢转换效率的关键。理论上高活性的基于赤铁矿的光阳极仍然需要从内到外进行修饰，以克服超快载流子复合和高反应势垒。在此，我们报告了一种具有配位单宁酸、Ni、Fe 和 Co（TA-NFC）的均匀超薄助催化剂，用于增强 F 掺杂的 Fe ₂ O _{3 的}光电化学性能纳米棒 (NR) 光阳极。结构中的 F 掺杂实现了更高的载流子密度和更低的电荷转移电阻，以加速光生电子和空穴的分离。此外，表面上的 TA-NFC 助催化剂有助于空穴注入并支持更快的水氧化动力学。最终，F–Fe ₂ O ₃ @TA–NFC NRs的光电流密度在 1.23 V 时与 RHE 相比急剧增加至 3.02 mA/cm ²，并且在低偏压下施加的偏置光子电流效率达到最大值 0.33% . 这项工作可能为提高基于半导体的光阳极的本征光电化学活性提供一种新颖且有前景的设计方案。