Factors Controlling the Redox Activity of Oxygen in Perovskites: From Theory to Application for Catalytic Reactions

Abstract

Abstract:Triggering the redox reaction of oxygens has become essential for the development of (electro) catalytic properties of transition metal oxides, especially for perovskite materials that have been envisaged for a variety of applications such as the oxygen evolution or reduction reactions (OER and ORR, respectively), CO or hydrocarbons oxidation, NO reduction and others. While the formation of ligand hole for perovskites is well-known for solid state physicists and/or chemists and has been widely studied for the understanding of important electronic properties such as superconductivity, insulator-metal transitions, magnetoresistance, ferroelectrics, redox properties etc., oxygen electrocatalysis in aqueous media at low temperature barely scratches the surface of the concept of oxygen ions oxidation. In this review, we briefly explain the electronic structure of perovskite materials and go through a few important parameters such as the ionization potential, Madelung potential, and charge transfer energy that govern the oxidation of oxygen ions. We then describe the surface reactivity that can be induced by the redox activity of the oxygen network and the formation of highly reactive surface oxygen species before describing their participation in catalytic reactions and providing mechanistic insights and strategies for designing new (electro) catalysts. Finally, we give a brief overview of the different techniques that can be employed to detect the formation of such transient oxygen species.

Advanced Bifunctional Oxygen Reduction and Evolution Electrocatalyst Derived from Surface‐Mounted Metal–Organic Frameworks

“…TheT afel slope trends of 1 À Xfrom À NH 2 to À H, À OCH 3 and À Br are consistent with the trends observed by XRD,X PS, Raman spectroscopy and UV/Vis.Acomparison of the calculated electron affinities of 1ÀXf urther supports the importance of the strain approach for enhanced the OER activity.L ow electron affinities of intercalated linkers BDC-(X) can increase the density of the unoccupied state of transition metals,b oost the binding strength between the active sites of the SURMOFDs and the OER reaction intermediates and further enhancing their OER activity. [30] As shown in Figure S20, NH 2 ÀBDC shows the lowest electron affinity (0.18 eV) and BrÀBDC (0.66 eV) shows the largest electron affinity.T he results match well with the observed trend; 1 À NH 2 shows the highest OER activity,w hile 1 À Br shows the lowest OER activity in the whole potential range above 1.45 Vvs. RHE.…”

Perovskite Electrocatalysts for the Oxygen Reduction Reaction in Alkaline Media

“…An in-depth discussion of the role of oxygen in perovskites for catalytic reactions, including the ORR, is reported by Yang and Grimaud [191] in this Special Issue. The shown mechanism is loosely based on high temperature work of mixed oxide ion/electronic conductor (MIEC) oxides [169].…”

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

“…[6][7][8][9][10] Theoretical studies suggest that the catalytic activity of the four-electron transfer reaction forming molecular O 2 depends on strength and flexibility of the metal-oxygen bond, which can shift the redox activity from metal to lattice oxygen surface sites due to ligand hole formation. [7,28,34,39,40] Thus, an understanding of the underlying microscopic mechanisms, the nature of active sites, and catalyst stability is necessary to rationalize the search for active and stable catalysts.…”