Anion-Exchange Membrane–Photoelectrochemical Water Splitting Using Porous Hematite Photoanodes

The requirement for liquid electrolytes to maintain their ionic conductivity hinders the practical implementation of photoelectrochemical (PEC) systems. Here, a membrane electrode assembly was fabricated by incorporating porous α-Fe 2 O 3 (hematite)-based photoanodes with an anion-exchange membrane (AEM). AEM–PEC water splitting was demonstrated in pure water without supporting electrolytes over porous hematite photoanodes under visible-light irradiation. This PEC system was operational even under low conductivity and near-neutral conditions (∼1 mS/m and pH ∼ 9). Action spectral analysis confirmed a visible-light response extending up to 600 nm, surpassing that of previously reported photoelectrodes with solid-electrolyte membranes.