Harnessing Red Sea Water for Green Hydrogen: Palladium Dioxide-Decorated Polypyrrole Electrode
摘要
The development of efficient and stable photocathodes for seawater splitting is critical for advancing sustainable hydrogen production. Here, the fabrication of a PdO2–PPy/PPy core–shell photocathode via a facile one-pot deposition strategy is reported, where PdO2–PPy nanostructures are uniformly encapsulated within a conductive polypyrrole (PPy) framework. The resulting architecture consists of PdO2 cores with average diameters of ~110 nm surrounded by PPy shells of ~30 nm thickness, ensuring intimate interfacial contact and enhanced charge transport. Structural analysis by x-ray diffraction (XRD) confirms the crystalline nature of PdO2 with an average crystallite size of ~5 nm, while optical characterization reveals a narrow bandgap of 2.0 eV, favorable for visible-light harvesting. The photoelectrochemical behavior of the PdO2–PPy/PPy photocathode was systematically investigated using natural Red Sea water as well as a compositionally matched artificial seawater medium. Under illumination, the system exhibited photocurrent densities of ~1.25 mA cm−2 and ~1.38 mA cm−2 in artificial and natural seawater, respectively. Optical filter studies across 730–340 nm demonstrated a clear wavelength-dependent enhancement in photocurrent, with Jph increasing from 1.15 mA cm−2 to 1.35 mA cm−2 at shorter wavelengths. Furthermore, hydrogen evolution rates reached 1.8 µmol h−1 cm−2 and 1.7 µmol h−1 cm−2 in natural and artificial seawater, respectively, underscoring the robustness of the photocathode across diverse conditions. These findings highlight the PdO2–PPy/PPy core–shell photocathode as a promising platform for direct seawater-to-hydrogen conversion, offering both efficiency and stability, and paving the way toward scalable industrial applications in green hydrogen production.