Triggered lattice-oxygen oxidation with active-site generation and self-termination of surface reconstruction during water oxidation.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38051768.
- Also identified by DOI 10.1073/pnas.2312224120 and PMC identifier 10723130.
- Licence recorded as CC BY-NC-ND.
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Abstract
To master the activation law and mechanism of surface lattice oxygen for the oxygen evolution reaction (OER) is critical for the development of efficient water electrolysis. Herein, we propose a strategy for triggering lattice-oxygen oxidation and enabling non-concerted proton-electron transfers during OER conditions by substituting Al in La<sub>0.3</sub>Sr<sub>0.7</sub>CoO<sub>3-</sub><i><sub>δ</sub></i>. According to our experimental data and density functional theory calculations, the substitution of Al can have a dual effect of promoting surface reconstruction into active Co oxyhydroxides and activating deprotonation on the reconstructed oxyhydroxide, inducing negatively charged oxygen as an active site. This leads to a significant improvement in the OER activity. Additionally, Al dopants facilitate the preoxidation of active cobalt metal, which introduces great structural flexibility due to elevated O 2<i>p</i> levels. As OER progresses, the accumulation of oxygen vacancies and lattice-oxygen oxidation on the catalyst surface leads to the termination of Al<sup>3+</sup> leaching, thereby preventing further reconstruction. We have demonstrated a promising approach to achieving tunable electrochemical reconstruction by optimizing the electronic structure and gained a fundamental understanding of the activation mechanism of surface oxygen sites.