Investigation of porous silicon photocathodes for photoelectrochemical hydrogen production

Solar energy conversion is made possible through the use of silicon as a photoelectrode material. Nanostructuring of the silicon substrate further improves solar energy conversion by virtue of its antireflective surface and tuneable band gap energies. In this work, we investigated the optimal etching conditions to fabricate porous silicon films, in terms of pore size and layer thickness. The stability of the sample was improved by passivating the porous layer with methyl groups via the electrografting of methyl iodide. A bio-inspired iron sulphur carbonyl electrocatalyst loaded on the electrografted porous silicon was studied. A photocurrent density of −2.8 mA/cm² and 46.8 μmol/h of hydrogen gas were observed for the electrografted porous silicon coated with bio-inspired iron sulphur carbonyl electrocatalyst.