Heterojunction of Silicon Nanowires and TiO₂ via Bioinspired Polymer for Efficient Photocatalytic Hydrogen Evolution

The use of photocatalytic hydrogen evolution depends on the availability of an efficient photocatalyst. This experiment aimed to create a type-II heterojunction between silicon nanowires and titanium dioxide bridged by a biomimetic polydopamine layer for efficient photocatalytic hydrogen production. This delivered adhesion, mechanical durability, outstanding wettability, and effective transfer of photogenerated charge carriers. Electron microscopy provided insight into the morphology and integration of the nanocoatings, while X-ray photoelectron spectroscopy confirmed the chemical structure of the nanocomposite before and after photocatalytic tests. These included voltammetric and impedance spectroscopy studies under UV-vis irradiation, which revealed a significant and stable photocurrent (up to 300 μA cm^-2) and facilitated electron transfer through the hybrid photocatalyst. Finally, we composed a band diagram of the obtained remote heterojunction, which allowed us to understand its operation principles. We believe this approach provides a different perspective on type-II heterojunctions and allows for further development of the band alignment strategies.