Unraveling the modulation essence of p bands in Co-based oxide stability on acidic oxygen evolution reaction

The oxygen evolution reaction (OER) electrocatalysts, which can keep active for a long time in acidic media, are of great significance to proton exchange membrane water electrolyzers. Here, Ru-Co₃O₄ electrocatalysts with transition metal oxide Co₃O₄ as matrix and the noble metal Ru as doping element have been prepared through an ion exchange–pyrolysis process mediated by metal-organic framework, in which Ru atoms occupy the octahedral sites of Co₃O₄. Experimental and theoretical studies show that introduced Ru atoms have a passivation effect on lattice oxygen. The strong coupling between Ru and O causes a negative shift in the energy position of the O p-band centers. Therefore, the bonding activity of oxygen in the adsorbed state to the lattice oxygen is greatly passivated during the OER process, thus improving the stability of matrix material. In addition, benefiting from the modulating effect of the introduced Ru atoms on the metal active sites, the thermodynamic and kinetic barriers have been significantly reduced, which greatly enhances both the catalytic stability and reaction efficiency of Co₃O₄.