Dragon fruit-inspired quantum scale-designed photocathodes

The development of environment-friendly, high-performance, and low-cost photoelectrocatalysts is hindered by the low separation efficiency of electron-hole pairs, corrosion from light illumination, and harsh environments. In this study, we propose a hierarchical structured nanocomposite that addresses all the aforementioned problems. Our design is inspired by the structure of a dragon fruit, in which CuInS2/CdS quantum dots (QDs) are encapsulated with TiO2 nanofilms. CuInS2/CdS QDs possess effective charge separation capability but suffer from photocorrosion, whereas TiO2 exhibits the opposite behavior. As a result of this hierarchical arrangement, the complementary system exhibits outstanding durability (lasting longer than 240 h without decay) and high-performance photoelectrocatalysis activity (potentials of approximately −0.219 V to obtain current densities of 100 mA cm−2) under light illumination.