Sustainable hydrogen generation from seawater using a Ni(III) oxide/poly(2-chloro benzeneamine) nanocomposite without sacrificial agents

The global demand for clean and sustainable hydrogen fuels has driven the search for efficient photocathode materials capable of converting seawater directly into hydrogen without sacrificial agents. In this study, we report the fabrication of a Ni(III) oxide/poly(2-chlorobenzeneamine) (Ni 2 O 3 /P2CBA) nanocomposite through a simple one-pot dark oxidation route using NiCl 2 as the oxidizing agent. The as-synthesized nanocomposite exhibits high crystallinity with an average crystallite size of ∼12 nm, and a coral-like porous morphology (∼100 nm pore size), as confirmed by XRD and SEM analyses. Optical studies reveal a direct bandgap of 1.9 eV, enabling broad absorption extending from the visible to the infrared region. The Ni 2 O 3 /P2CBA photocathode was evaluated for hydrogen evolution from both natural Red Sea seawater and artificial seawater under simulated solar illumination. The measured photocurrent densities ( J ph ) reached −0.026 mA cm −2 for natural seawater and −0.024 mA cm −2 for artificial seawater, corresponding to hydrogen generation rates of 0.5 and 0.4 μmol h −1 cm −2 , respectively. These findings demonstrate that the Ni 2 O 3 /P2CBA nanocomposite offers an efficient, stable, and scalable platform for sacrificial-agent-free hydrogen generation from seawater. The simple synthesis, strong optical response, and environmental compatibility highlight its promise for future large-scale renewable hydrogen production systems.