Materials that are able to catalyze both half reactions of water splitting, i.e., oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are highly sought after. Bifunctional electrocatalytic activity for water-splitting in layered oxides is reported in this work. A series of layered oxides, with general formula AA’BO<sub>4-δ</sub>, featuring a range of compositions with different ratios of Fe and Co on the B-site and Sr/La on the A/A’-sites have been synthesized. They contain 2-dimensional layers of octahedrally coordinated transition metals separated by alkaline earth or rare earth metals. Remarkably, these materials are able to catalyze both half-reactions of water-splitting, <i>i.e.,</i> oxygen-evolution reaction (OER) and hydrogen-evolution reaction (HER). The electrical charge transport properties and electrocatalytic activities are methodically enhanced by changing the ratios of transition metals on the B-site. The most active catalyst in the series features the highest degree of polyhedral distortion, highest conductivity and the presence of oxygen deficiency. These factors, combined with a favorable electronic configuration, result in enhanced electrocatalytic properties.

Electrical charge transport property and electrocatalytic activity of layered oxides

ACS Fall 2021

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