The integration of Earth‐abundant materials with light‐harvesting absorbers to create a high‐efficiency photocathode is a promising approach for solar‐driven water splitting. It is essential for such systems to provide a practical photocurrent response and overpotential for driving hydrogen production. Herein, electrodeposited Ni–M (M = Co, Fe, Mo) is investigated as a surface catalyst onto p‐type silicon micropillar arrays for solar‐driven hydrogen evolution, and the generation of catalytic active species by in situ and ex situ tracking methods is directly observed. The dynamic electronic and atomic structures of highly active surface catalysts are identified during photocatalysis in alkaline condition. Furthermore, the incorporation of high‐valence Mo species acts as a key promoter for triggering the in situ formation of active Ni²⁺ species on the surface of alloys. These findings offer guidelines for the design and development of highly efficient catalytic photocathodes.

中文翻译：

---

电沉积双金属p-Si微柱阵列光电阴极的原位观察

将富含地球的材料与集光吸收体集成在一起以创建高效的光电阴极，是太阳能驱动水分解的一种有前途的方法。对于此类系统，必须提供实用的光电流响应和超电势来驱动制氢。在此，研究了电沉积的Ni–M（M = Co，Fe，Mo）作为p型硅微柱阵列上的表面催化剂，以太阳能驱动氢的释放，以及通过原位和异位跟踪方法生成催化活性物质直接观察到。在碱性条件下的光催化过程中，可以确定高活性表面催化剂的动态电子和原子结构。此外，高价态Mo的掺入是触发活性Ni原位形成的关键促进剂合金表面有²⁺种。这些发现为高效催化光阴极的设计和开发提供了指导。