Nano-hetero-structured thin films, ZnO/Ag-(α)Fe2O3, with n/n junction, as efficient photoanode for renewable hydrogen generation via photoelectrochemical water splitting

Abstract Significant gains in PEC water splitting photocurrent were recorded using n/n junction bi-layered nano-hetero-structured (BNHS) thin films, ZnO/Ag-(α)Fe2O3, as photoanode. Films, synthesized over ITO (In:SnO2) glass plates, were characterized by X-ray diffractometry, field emission-scanning electron microscopy, atomic force microscopy, UV–visible spectroscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy. PEC cell, fabricated through electrical contacting of BNHS films (3% Ag incorporation)/electrolyte (0.1 M NaOH, pH 13, temperature 32 ± 3.6 °C) junction working electrode with platinum counter electrode and saturated calomel reference electrode, yielded nearly 2 and 20 fold increment in photocurrent, against monolayered pristine ZnO and (α)Fe2O3 thin films, respectively. Marked gain in PEC cell-response towards water splitting was attributed to high active surface area and n/n hetero-junction that favored the separation and transfer of photogenerated charge carriers.