One-pot fabrication of highly porous morphology of ferric oxide-ferric oxychloride/poly-O-chloroaniline nanocomposite seeded on poly-1H pyrrole: Photocathode for green hydrogen generation from natural and artificial seawater

Abstract

A novel photocathode has been fabricated, featuring a highly porous ferric oxide-ferric oxychloride/poly-O-chloroaniline (Fe2O3-FeOCl/POCA) nanocomposite, integrated onto a poly-1H pyrrole substrate. This photocathode was synthesized using a one-pot technique, which involves the oxidation of o-chloroaniline in the presence of iron sources, resulting in the incorporation of iron oxide and iron oxychloride within the polymer matrix. The photocathode exhibits broad optical absorption extending into the IR region and has a promising bandgap of 1.74 eV, making it a strong candidate for hydrogen gas generation within a constructed three-electrode cell. The photocathode’s performance in natural seawater is impressive, with an estimated hydrogen production rate of 20 µmol/h per 10 cm2. Electrochemical measurements indicate a current density of −0.015 mA/cm2 under these conditions. When tested with artificial seawater that is free of heavy metals, the current density (J ph) is slightly lower at −0.013 mA/cm2. Furthermore, the photocathode demonstrates excellent sensitivity to various photon energies across wavelengths ranging from 730 to 340 nm, achieving J ph values of −0.0145 and −0.012 mA/cm2, respectively. The green chemistry approach used in this photocathode’s fabrication, combined with its environmentally friendly operation, highlights its potential for commercial applications. This development could pave the way for industrial-scale production of photoelectrodes designed to convert seawater into hydrogen gas, contributing to sustainable energy solutions.

Keywords

• ferric oxide-ferric oxychloride
• poly-o-chloroaniline
• nanocomposite
• renewable energy
• green hydrogen