Oxygen evolution electrocatalysts with high activity, extended durability, and lower costs are needed to further the development of proton-exchange membrane (PEM) electrolyzers. Tuning the interaction of metals within bimetallic alloys allows the surface atomic and electronic structure to be altered and provides an approach to obtain acidic oxygen evolution reaction (OER) electrocatalysts with increased activity and stability. Our group has recently explored unsupported metallic Ni-Ir alloy nanoarchitectures which show significantly higher OER activities compared with baseline IrO₂ catalysts, however lower relative stability was also obtained.¹ Compared with iridium-based catalysts, ruthenium-based catalysts (metallic Ru and RuO_x) have shown the highest reported activities of any acidic OER catalysts. In addition, ruthenium has lower cost and higher supply compared with iridium. However, Ru-based catalysts show significant instability with substantial dissolution that leads to catalyst degradation. We have investigated Ru-metal nanostructures as a route to obtain OER catalysts with high activity and stability. Bimetallic nanostructures were synthesized using sol-gel chemistry routes and subsequent thermal treatments under reducing conditions. The structure and morphology were determined by X-ray diffraction and scanning electron microscopy. Cyclic voltammetry was used to investigate the surface structure and the effect of anodic potentials on the surface. Rotating disk electrode measurements were used to evaluate the electrochemical oxygen evolution activity and stability of the bimetallic nanostructures which were compared with baseline ruthenium OER catalysts.

References

1. Godínez-Salomón, F.; Albiter, L.; Alia, S. M.; Pivovar, B. S.; Camacho-Forero, L. E.; Balbuena, P. B.; Mendoza-Cruz, R.; Arellano-Jimenez, M. J.; Rhodes, C. P., Self-Supported Hydrous Iridium–Nickel Oxide Two-Dimensional Nanoframes for High Activity Oxygen Evolution Electrocatalysts. ACS Catal. 2018, 8, 10498-10520.