摘要： Silicon (Si) is an attractive photoanode material for photoelectrochemical (PEC) water splitting. However, Si photoanode is highly challenging due to its poor stability and catalytic inactivity toward oxygen evolution reaction (OER). Integration of highly active electrocatalysts with Si photoanodes has been considered as an effective strategy to improve OER performance through accelerates reaction kinetics and inhibits Si photocorrosion. In this work, ultra-small NiFe nanoparticles are deposited onto n-Si/Ni/NiOOH surface to improve the activity and stability of Si photoanode by engineering the electrocatalyst and Si interface. Ultra-small NiFe can introduce oxygen vacancies via modulating the local electronic structure of Ni hosts in NiOOH electrocatalyst for fast charge separation and transfer. Besides, NiFe nanoparticles also can serve as co-catalyst exposure more active sites and as protection layer prevents Si photocorrosion. The as-prepared n-Si/Ni/NiOOH/NiFe photoanode exhibits excellent OER activity with an onset potential of 1.0 V versus reversible hydrogen electrode (RHE) and a photocurrent density of ～25.2 mA cm-2 at 1.23 V versus RHE. This work provides a promising approach to design high-performance Si photoanodes by surface electrocatalyst engineering.