Large energy barriers and sluggish kinetics of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), which are the two half reactions of water splitting, hinder the water splitting efficiency. Exploring and designing new cost-effective OER/HER catalysts is an important task. Ruddlesden Popper (RP) layered oxides derived from perovskites have intriguing properties originating from different compositions with various metal ions. We attempted to tune the magnetic, electrical, and electrochemical properties of RP layered oxides by changing their A-site and B-site ions. We have synthesized RP materials where A-site is Sr/La and B-site is a combination of transition metals, including manganese, iron and cobalt. From the investigation of magnetic properties, we observed a shift of the magnetic transition temperature with the change of B site metal. Importantly, we studied the catalytic activity of the synthesized materials to split water electrochemically and demonstrated that they can catalyze both OER and HER. Interestingly, we observed a systematic enhancement of the electrocatalytic activity and stability with the change of the B-site metal. The variable temperature studies also demonstrated a systematic trend in electrical conductivity that matches the OER and HER trend. These systematic changes are also present in the OER/HER kinetics.

Electrocatalysis for water splitting using two isostructural layered oxides

ACS Spring 2022

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