Systematic Study of Descriptors for Oxygen Evolution Reaction Catalysis in Perovskite Oxides

Abstract

Ever proposed descriptors of catalytic activity for oxygen evolution reaction (OER) were systematically investigated. A wide variety of stoichiometric perovskite oxides ABO 3 (A = Ca, Sr, Y, La; B = Ti, V, Cr, Mn, Fe, Co, Ni, Cu) were examined as OER catalysts. The simplest descriptor, e g electron number of transition metal ion at B-site, was not applicable for OER overpotentials (η) of the compounds tested in this study. Another descriptor, oxygen 2p band center relative to Fermi energy (ε 2p), was not necessarily adequate for the most part of perovskite oxides. Eventually, a recently proposed descriptor, charge-transfer energy (Δ), displayed a linear relationship with η the most reasonably. Since Δ values were obtained from theoretical calculations, not only by spectroscopic experiments, systematic exploration for a wide range of compounds including hypothetical ones could be allowed. This finding proposes the charge-transfer energy as the most helpful descriptor for design of perovskite oxide catalyst for OER.

Direct evidence of boosted oxygen evolution over perovskite by enhanced lattice oxygen participation

“…This is a good indication of the improved OER kinetics on the perovskite catalyst incorporating silicon because catalysts having a smaller Tafel slope tend to deliver significantly increased currents at only moderate increments of overpotential. A detailed comparison with literature results, as tabulated in Supplementary Table 4, suggests that the Si-incorporated Si-SCO catalyst compares favourably to the state-of-the-art perovskite catalysts such as BSCF, PBC and SNCF, among many others [7][8][9][10][11][12][13]18,19,31,[42][43][44][45][46][47] .…”

The Effect of Cation Mixing in LiNiO2 toward the Oxygen Evolution Reaction

“…Further studies showed a strong correlation between OER activity and oxygen p‐band center relative to the Fermi level through theoretical calculations [26] . Other parameters, including cations in octahedral sites and transition metal 3d – O 2p hybridization, have been widely studied by metal doping or partial element substitution [27–30] . Surface reconstruction mediated by transition metals has been reported to form active reaction sites, such as oxyhydroxide sites on the catalyst interface [31,32] .…”

Cation insertion to break the activity/stability relationship for highly active oxygen evolution reaction catalyst

“…Recent experimental results and theoretical studies pointed out that increasing the transition metal-oxygen bond covalency leads to an enhanced OER kinetics concomitant with the destabilization of the surface [12][13][14][15][16][17][18] . Screening a large variety of transition metal oxides, it could be shown that this phenomenon is related to the relative position of the Fermi level when compared to the reversible potential for water oxidation, as well as to the charge-transfer energy [19][20][21][22] . In short, lowering the charge-transfer energy triggers the redox activity of oxygen ligand, leading to the involvement of lattice oxygen into the OER following the so-called lattice oxygen evolution mechanism.…”