Oxygen evolution reaction activity and underlying mechanism of perovskite electrocatalysts at different pH

Abstract

The members of the perovskite oxide family have been vastly explored for their potential as active electrocatalysts for an efficient anodic reaction (i.e. the oxygen evolution reaction, OER) of the water splitting process.

Correlation between Oxygen Vacancies and Oxygen Evolution Reaction Activity for a Model Electrode: PrBaCo2O5+δ

“…This double perovskite is known in the literature for its ability to accommodate a broad range of oxygen vacancies, [10] making it the ideal candidate to validate the impact of the lattice oxygen vacancies in the OER activity. Furthermore, the OER activity of PBCO nanopowder was found to linearly scale with the electrolyte pH value in alkaline environment, which is commonly taken as an indicator of the occurrence of the LOER mechanism [11] . For a detailed analysis of the average amount and distribution of oxygen atoms in the bulk PBCO samples, powder neutron diffraction has been used.…”

Fundamental Understanding and Application of Ba0.5Sr0.5Co0.8Fe0.2O3−δPerovskite in Energy Storage and Conversion: Past, Present, and Future

“…Kim et al further studied the catalytic performance of BSCF in water electrolytes across a wide range of pH (7−14). 180 It was found that under near-neutral pH (7−9) BSCF showed a zeroth order relationship between OER activity and pH where the conventional AEM pathway dominates, while under high alkaline pH (12−14) BSCF revealed a first-order relationship where the LOER mechanism takes over. It should be noted that the various pH conditions adopted in this study also differ in the cation or anion species, which might have an impact on the catalytic studies.…”

“…Nonetheless, additional investigations are required to understand the cation effect in further detail. Kim et al further studied the catalytic performance of BSCF in water electrolytes across a wide range of pH (7–14) . It was found that under near-neutral pH (7–9) BSCF showed a zeroth order relationship between OER activity and pH where the conventional AEM pathway dominates, while under high alkaline pH (12–14) BSCF revealed a first-order relationship where the LOER mechanism takes over.…”

Recent advances in non-precious group metal-based catalysts for water electrolysis and beyond

“…15a). 116,117 However, recent studies on perovskite oxide catalysts have revealed a new OER mechanism based on the involvement of lattice oxygens in perovskite, the so-called lattice oxygen evolution reaction (LOER) mechanism (Fig. 15a).…”

“…15a). 117–119 Particularly under alkaline conditions, perovskite oxide catalysts have recently been central to the study of the LOER mechanism to improve the OER activity. Suntivich et al systematically investigated the OER activity of perovskite oxides and suggested that the e g occupancy of the 3d electron can be employed as an effective descriptor.…”