The combination of noble metal catalysts and semiconductors presents a typical avenue for boosting photoelectrochemical (PEC) hydrogen production. However, noble metal catalysts directly deposited on Si can easily aggregate into large clusters and tend to peel off from the Si surface, thereby limiting the effective use of noble metal and PEC performance of the Si photocathode. Here, we report that oxygen-vacancy-rich Ni(OH)₂ nanosheets are developed as an ideal multifunctional layer between an Ir catalyst and Ni protected Si photocathode, which could not only effectively capture and stabilize atomic Ir via the newly formed O–Ir–O bonds, but also significantly enhance the reaction kinetics by accelerating charge and mass transport and reducing the energy barriers of both the Volmer and Tafel steps. A benchmarking applied bias photon-to-current efficiency (ABPE) of 12.4% and a sustainable stability of more than 300 h are achieved under AM1.5G one sun illumination, outperforming all the previously reported Si photocathodes in alkaline media. Our findings emphasize the importance of the interlayer for the Si photocathode and offer the avenue to achieve highly efficient and durable PEC devices.

中文翻译：

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富氧空位氢氧化镍纳米片：Ir 和 Si 之间的多功能层，用于增强碱性介质中的太阳能制氢

贵金属催化剂和半导体的结合是促进光电化学 (PEC) 制氢的典型途径。然而，直接沉积在Si上的贵金属催化剂很容易聚集成大簇并容易从Si表面剥离，从而限制了贵金属的有效利用和Si光电阴极的PEC性能。在这里，我们报道了富含氧空位的 Ni(OH) ₂纳米片被开发为 Ir 催化剂和 Ni 保护的 Si 光电阴极之间的理想多功能层，它不仅可以有效地捕获和稳定原子 Ir新形成的 O-Ir-O 键，还通过加速电荷和质量传输以及降低 Volmer 和 Tafel 步骤的能垒显着增强了反应动力学。在 AM1.5G 一次太阳光照下，基准应用的偏置光子电流效率 (ABPE) 为 12.4%，可持续稳定性超过 300 小时，优于之前报道的所有在碱性介质中的硅光电阴极。我们的研究结果强调了中间层对于 Si 光电阴极的重要性，并为实现高效耐用的 PEC 器件提供了途径。