Engineering of the d‐Band Center of Perovskite Cobaltite for Enhanced Electrocatalytic Oxygen Evolution

Abstract

Great efforts have been made to understand and upgrade the kinetically sluggish oxygen evolution reaction (OER). In this study, a series of V‐doped LaCoO3 (V‐LCO) OER electrocatalysts with optimized d‐band centers are fabricated. When utilized as an electrode for the OER, as‐formed LaCo0.8V0.2O3 (V‐LCO‐II) requires an overpotential of only 306 mV to drive a geometrical catalytic current density of 10 mA cm−2. Furthermore, at a given overpotential of 350 mV, the OER current density of V‐LCO‐II is about 22 times that of pure LaCoO3 (LCO) nanoparticles. Tailoring of the d‐band center by V doping facilitates the adsorption of OER intermediates and promotes the formation of amorphous active species on the surface of LCO through the exchange interaction between high‐spin V4+ and low‐spin Co2+. This work may create new opportunities for developing other highly active OER catalysts through d‐band center engineering.

Safeguarding the RuO2 phase against lattice oxygen oxidation during acidic water electrooxidation

“…The vacancy formation and the increasing Pt shifts the d-band center lower from −1.26 eV to −1.68 eV, indicating the weaker binding to adsorbates. 49,50 These results are consistent with the free energies of intermediates described above. Thus, the Pt-dopant and metal vacancy in RuO 2 can control the bond strength between surface and intermediates, resulting in the improvement of OER performance.…”

Bulk and Surface Properties Regulation of Single/Double Perovskites to Realize Enhanced Oxygen Evolution Reactivity

“…268 mV, Figure b), in contrast to the nearly unchanged potential exhibited by the DP material. To the best of our knowledge, the SP/DP material has one of the lowest overpotentials at 10 mA cm −2 in alkaline solution among the reported perovskite oxide OER electrocatalysts (Figure c and Table S3), including DP oxides (e.g., La 2 NiMnO 6 , PrBaCo 2 O 5.75 , Sr 2 Fe 0.8 Co 0.2 Mo 0.65 Ni 0.35 O 6 , and SrCo 0.2 Fe 0.2 W 0.4 O 3−δ ) and SP oxides (e.g., F substituted Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ , SrCo 0.5 Fe 0.5 O 3−δ , SrNb 0.1 Co 0.7 Fe 0.2 O 3−δ nanorods, and LaCo 0.8 V 0.2 O 3 ). Additionally, the SP/DP material has superior catalytic activity to noble metal oxides, such as IrO 2 , hybrids, such as BC1.5MN and LSM‐20‐Co, transition metal phosphides, such as 12‐CoNiP, and spinel oxides, such as CoFe 2 O 4 and Zn 0.35 Co 0.65 O …”

“…(b) Chronopotentiometry curve of SP/DP oxide at a fixed current density of 10 mA cm −2 . (c) OER activity of various materials in 1.0 m KOH showing the overpotential at 10 mA cm −2 , including noble metal oxides (1‐IrO 2 ), double perovskite oxides (2‐La 2 NiMnO 6 , 3‐PrBaCo 2 O 5.75 , 4‐Sr 2 Fe 0.8 Co 0.2 Mo 0.65 Ni 0.35 O 6 , and 5‐SrCo 0.2 Fe 0.2 W 0.4 O 3−δ ), single perovskite oxides (6‐F substituted Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ , 7‐SrCo 0.5 Fe 0.5 O 3−δ , 8‐SrNb 0.1 Co 0.7 Fe 0.2 O 3−δ nanorods, and 9‐LaCo 0.8 V 0.2 O 3 ), hybrids (10‐BC1.5MN and 11‐LSM‐20‐Co), transition metal phosphides (12‐CoNiP), and spinel oxides(13‐CoFe 2 O 4 and 14‐Zn 0.35 Co 0.65 O).…”

Development of Perovskite Oxide‐Based Electrocatalysts for Oxygen Evolution Reaction

“…The optimal composition LaCo 0.8 V 0.2 O 3 required an overpotential of only 306 mV to reach 10 mA cm −2 , far better than un-doped LaCoO 3 (430 mV). [59] The OER performance of LaCoO 3 can also be improved through the incorporation of Ni into the B-site because of the formation of new redox Ni 3+ /Ni 2+ and higher Co 3+ /Co 2+ ratios, which can promote the adsorption of oxygen on the catalytic surface and improve the strength of the CoO bond. [60] Recently, J. Schmidt et al [61] investigated the functional role of Fe-substituted in Co-based perovskite oxide catalyst for OER, denoted as La 0.2 Sr 0.8 Co 1−x Fe x O 3−δ and Ba 0.5 Sr 0.5 Co 1−x Fe x O 3−δ (x = 0 and 0.2).…”