Cuprous oxide (Cu₂O) is an attractive photo-electrocatalyst for sustainable hydrogen production. The main issues limiting the use of Cu₂O as a photocathode are the severe electron-hole recombination and photo-corrosion in aqueous electrolyte. Herein, to address the above issues, amorphous SiO_x overlayers have been deposited on the surface of Cu₂O as a protective cover using a facile dip-coating method. The overall PEC performances have been greatly improved, as evidenced by the increased photocurrent density (3.1 times of bare Cu₂O) and improved stability (3.8 times of bare Cu₂O). The structure and PEC characterizations prove that Si has been gradient-doped into the Cu₂O, leading to a downward band bending from the bulk to the surface region, which promotes the charge separation and transfer efficiently. In addition, the amorphous SiOx layers serve as protection layers and prevent the Cu₂O from direct contact with the electrolyte, maintaining a high photocurrent density over the stability test. Decoration with Pt catalyst has further boosted the photocurrent density to be 2.8 mA cm⁻² at 0 V vs. RHE with better stability, indicating the synergistic effect of SiOx layer and Pt catalyst This work provides a facile strategy to improve the PEC activity and stability of Cu₂O, which may be extended to other systems with photo-corrosion problems, such as BiVO₄ or ZnO.

氧化亚铜（Cu ₂ O）是用于可持续制氢的有吸引力的光催化剂。限制将Cu ₂ O用作光电阴极的主要问题是水性电解质中的严重的电子-空穴复合和光腐蚀。在此，为了解决上述问题，已经使用简便的浸涂法在Cu ₂ O的表面上沉积了非晶SiO _x覆盖层作为保护罩。通过增加的光电流密度（裸Cu ₂ O的3.1倍）和提高的稳定性（裸Cu ₂ O的3.8倍）可以证明，整体PEC性能得到了极大的改善。结构和PEC表征证明Si已被梯度掺杂到Cu _2中O，导致从主体到表面区域的向下带弯曲，这促进了电荷的分离和有效转移。另外，无定形SiO x层用作保护层并防止Cu ₂ O直接与电解质接触，从而在稳定性测试中保持高光电流密度。Pt催化剂的装饰将0V时的RHE的光电流密度进一步提高到2.8 mA cm ^-2，具有更好的稳定性，表明SiOx层和Pt催化剂的协同作用。这项工作为提高PEC活性和稳定性提供了一种简便的策略。的铜₂ O，其可被扩展到其它系统的光腐蚀问题，如BiVO ₄或ZnO。