Dynamic shrinkage of metal-oxygen bonds in atomic Co-doped nanoporous RuO2 for acidic oxygen evolution

The design of highly active and stable catalysts for the oxygen evolution reaction (OER) in acidic media has become an attractive research area for the development of energy conversion and storage technologies. However, progress in this area has been limited by the poor understanding of the dynamic active structure of catalysts under realistic OER conditions. Here, an atomic Co-doped nanoporous RuO2 electrocatalyst, which exhibited excellent OER activity and stability in acidic conditions, was synthesized through annealing and etching of a nanoporous Co-Ru alloy. Operando X-ray absorption spectroscopy results confirmed that the etching strategy produced abundant oxygen vacancies around the metal centers in the atomic Co-doped nanoporous RuO2 electrocatalyst. These vacancies created contracted metal-oxygen ligand bonds under realistic OER conditions. The dynamic structural evolution of the synthesized electrocatalyst allowed them to experience lower kinetic barriers during OER catalysis, resulting in enhanced catalytic activity and stability. This study also provided atomic details on the active structure of the electrocatalyst and the influence of their structural evolution on OER activity.