A theory is used to understand how oxygen leaves or evolves from different metal oxides.
Oxygen can come from the oxide itself, this can make some catalysts better.
Energy needed to bind oxygen changes when replacing a ruthenium atom with a nickel atom.
Placing nickel atoms at certain spots on the oxide weakens oxygen bonds and aids its release.
Different mechanisms investigated for oxygen release involve multiple metals or 'popout' oxygen evolve.
Certain specific points on the oxide, like Ni-Ni or AC2, are efficient but not expected to be filled before reaction.
Oxygen evolution depends on the presence of Ru-Ni bridge sites.
Nickel atoms group together differently based on their concentration.
Presence of nickel increases oxygen evolution, but too much nickel can lower it.
Clusters of titanium can activate oxygen release at high electrode potentials.
A method was developed to predict oxygen evolution in particular oxides, relating structure to activity.
Data suggests max oxygen activity with nickel content between 10%-20%, but no activity with low titanium content.
We developed a density functional theory-based computational approach to evaluate the tendency of lattice oxygen evolution in various catalyst surfaces. Our model predicts different lattice oxygen evolution behaviors in surfaces of RuO2, mixed Ru-Ni oxide, and mixed Ru-Ti oxide, with some discrepancies likely caused by structural defects in the studied materials.
We're explaining the oxygen evolving process via Volmer-Heyrovsky and Volmer-Tafel mechanisms. However, an alternative mechanism involving lattice oxygen shows that oxygen from the catalyst's lattice contributes to the overall oxygen evolution. The participation of lattice oxygen improves the overall oxygen evolving activity of some catalysts, especially in Ni-based perovskites and RuO2 and IrO2 based catalysts.