Titanosilicate ETS-10-Modified Cu2O for Enhanced Visible-Light Photoelectrochemical Activity

Copper(I) oxide (Cu2O)-based photocathodes are promising materials for carbon dioxide (CO2) reduction under visible light due to copper’s abundance and favorable energy band alignment. However, Cu2O suffers from photocorrosion and chemical instability. Here, we present a novel approach utilizing a porous titanosilicate material (ETS-10) as a protective layer for Cu2O, addressing these limitations. The Cu2O was electrodeposited and coated with a thin ETS-10 layer, which prevents photocorrosion, enhances charge separation and transfer, and facilitates CO2 capture through its highly porous structure. Comprehensive structural, compositional, and morphological analyses confirmed that ETS-10 effectively stabilized Cu2O while maintaining its electronic properties (UV–Vis, XPS). The Cu2O/ETS-10 photocathode exhibited a 25% enhancement in the photocurrent density at 0.0–0.1 V vs. RHE and significantly improved stability compared to bare Cu2O. The thin ETS-10 layer acted as a passivation layer, improving charge transfer via tunneling mechanisms. This study introduces a multicomponent photocathode system, demonstrating a new application of ETS-10 in photoelectrochemical cells. The results highlight the potential of ETS-10 to enhance the efficiency and stability of photocathodes, offering a pathway for the design of advanced systems for solar-driven CO2 reduction and artificial photosynthesis.