SrNb_0.1Co_0.7Fe_0.2O_3−δ Perovskite as a Next‐Generation Electrocatalyst for Oxygen Evolution in Alkaline Solution

Abstract

The perovskite SrNb0.1 Co0.7 Fe0.2 O3-δ (SNCF) is a promising OER electrocatalyst for the oxygen evolution reaction (OER), with remarkable activity and stability in alkaline solutions. This catalyst exhibits a higher intrinsic OER activity, a smaller Tafel slope and better stability than the state-of-the-art precious-metal IrO2 catalyst and the well-known BSCF perovskite. The mass activity and stability are further improved by ball milling. Several factors including the optimized eg orbital filling, good ionic and charge transfer abilities, as well as high OH(-) adsorption and O2 desorption capabilities possibly contribute to the excellent OER activity.

A tailored double perovskite nanofiber catalyst enables ultrafast oxygen evolution

“…The OER performance of the ultrafine PBSCF-III nanofiber was superior to that of the recently reported advanced perovskite catalysts with novel compositions11121314, nanostructures1115 and atmosphere-treated surfaces1718 in terms of iR -corrected η ( i is the current, R is the ohmic resistance), Tafel slope and catalyst mass loading in 0.1 M KOH (Fig. 2d, for example, η =0.358 V, Tafel slope of 52 mV dec −1 , 0.202 mg oxide  cm −2 disk for PBSCF-III are lower than η =∼0.55 V, Tafel slope of 129 mV dec −1 , 0.64 mg oxide  cm −2 disk for surface-modified BSCF (calcined at 950 °C under O 2 )18 and η =0.49 V, Tafel slope of 69 mV dec −1 , 0.25 mg oxide  cm −2 disk for ∼80 nm LaCoO 3 (ref.…”

“…1) and SrNb 0.1 Co 0.7 Fe 0.2 O 3− δ (ref. 14). However, the intrinsic activity degraded as the surface areas were increased for these cases.…”

“…We further demonstrate the controlled synthesis of PBSCF nanofibers with diameters from ∼196 to 20 nm to enhance the OER mass activity and understand the nanosize effect. Importantly, PBSCF nanofibers of ∼20 nm in diameter show markedly enhanced OER activities compared to that of the PBSCF powders, superior to the commercial IrO 2 catalyst and those of recently reported advanced perovskite catalysts11121314151718. An enhancement in intrinsic activity of the same PBSCF material with decreasing the diameter to ∼20 nm (ultrafine nanofiber versus micron-sized powder) is observed, which is explained by favourable e g electron filling of ultrafine nanofiber, stronger adsorption of oxygen-containing adsorbates, possible surface reduction and heterostructure.…”

“…Unfortunately, the surface amorphization with formation of structural motifs with local order of edge-sharing octahedra was found for BSCF during the OER910. Strategies such as A/B cation substitution (or doping)11121314, nanostructure engineering111516 and surface treatment1718 have been successfully applied to enhance activity and/or stability. Double perovskites (AA′B 2 O 5+ δ ) were found to have stable structure during the OER due to proper O p -band centre position relative to the Fermi level19; in particular, PrBaCo 2 O 5+ δ (PBC) was identified with optimal intrinsic OER activity, comparable with that of BSCF catalyst19.…”

SrCo0.9Ti0.1O3−δ As a New Electrocatalyst for the Oxygen Evolution Reaction in Alkaline Electrolyte with Stable Performance

“…Even the BSCF electrode, with its wellknown high activity for the OER, showed a slight deterioration with the cycling, which could result from the partial change in its structure. 38 For example, after 100 continuous potential sweeps, the current density at 1.75 V showed a decrease from 10.5 to 8.6 mA cm −2 with a reduction of 18.1%. The stability of the commercial IrO 2 catalyst was also compared, as shown in Figures S10 and S11.…”