Renewable hydrogen production via water splitting in a photoelectrochemical (PEC) cell is a possible route to a hydrogen-based economy. Mixed metal oxide thin films have been shown to act as n-type and p-type semiconductors that could be used to drive the oxygen and hydrogen evolution reactions, respectively, in a PEC cell. We have explored the Fe, Cr, Al mixed metal oxide system through the inexpensive evaporative deposition of the corresponding metal hydroxide colloids in aqueous solution. Our research focused on a restricted evaporation technique to create circular shaped mixed metal oxide thin films. These thin films were characterized using 2D PEC data and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The PEC data revealed that solution deposition conditions, specifically ammonia concentration, affects the photoelectrochemical activity of the film in unexpected ways. The elemental composition of the Fe, Cr, Al mixed metal oxide films prepared from various ammonia concentrations was analyzed utilizing SEM-EDS. It was found that the deposited Fe-Cr-Al elemental molar ratio was heterogeneous across individual thin films and varied from the expected molar ratio present in the precursor colloids. Hypotheses to explain these observations will be presented, as well as ideas for further experimentation.

Creating cheaper mixed metal oxide films for photoelectrochemical production of renewable hydrogen

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.