Layered Quasi-Nevskite Metastable-Phase Cobalt Oxide Accelerates Alkaline Oxygen Evolution Reaction Kinetics.
basic_science · Level V
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- Record sourced from PubMed, PMID 38286031.
- Also identified by DOI 10.1021/acsnano.3c11199.
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Abstract
Clarifying the structure-reactivity relationship of non-noble-metal electrocatalysts is one of the decisive factors for the practical application of water electrolysis. In this field, the anodic oxygen evolution reaction (OER) with a sluggish kinetic process has become a huge challenge for large-scale production of high-purity hydrogen. Here we synthesize a layered quasi-nevskite metastable-phase cobalt oxide (LQNMP-Co<sub>2</sub>O<sub>3</sub>) nanosheet via a simple molten alkali synthesis strategy. The unit-cell parameters of LQNMP-Co<sub>2</sub>O<sub>3</sub> are determined to be <i>a</i> = <i>b</i> = 2.81 Å and <i>c</i> = 6.89 Å with a space group of <i>P</i>3̅<i>m</i>1 (No. 164). The electrochemical results show that the LQNMP-Co<sub>2</sub>O<sub>3</sub> electrocatalyst enables delivering an ultralow overpotential of 266 mV at a current density of 10 mA cm<sub>geo</sub><sup>-2</sup> with excellent durability. The <i>operando</i> XANES and EXAFS analyses clearly reveal the origin of the OER activity and the electrochemical stability of the LQNMP-Co<sub>2</sub>O<sub>3</sub> electrocatalyst. Density functional theory (DFT) simulations show that the energy barrier of the rate-determining step (RDS) (from *O to *OOH) is significantly reduced on the LQNMP-Co<sub>2</sub>O<sub>3</sub> electrocatalyst by comparing with simulated monolayered CoO<sub>2</sub> (M-CoO<sub>2</sub>).