Tackling activity-stability paradox of reconstructed NiIrO<sub>x</sub> electrocatalysts by bridged W-O moiety.
basic_science · Level V
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- Record sourced from PubMed, PMID 39632899.
- Also identified by DOI 10.1038/s41467-024-54987-4 and PMC identifier 11618364.
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Abstract
One challenge remaining in the development of Ir-based electrocatalyst is the activity-stability paradox during acidic oxygen evolution reaction (OER), especially for the surface reconstructed IrO<sub>x</sub> catalyst with high efficiency. To address this, a phase selective Ir-based electrocatalyst is constructed by forming bridged W-O moiety in NiIrO<sub>x</sub> electrocatalyst. Through an electrochemical dealloying process, an nano-porous structure with surface-hydroxylated rutile NiWIrO<sub>x</sub> electrocatalyst is engineered via Ni as a sacrificial element. Despite low Ir content, NiWIrO<sub>x</sub> demonstrates a minimal overpotential of 180 mV for the OER at 10 mA·cm<sup>-2</sup>. It maintains a stable 300 mA·cm<sup>-2</sup> current density during an approximately 300 h OER at 1.8 V<sub>RHE</sub> and shows a stability number of 3.9 × 10<sup>5</sup> n<sub>oxygen</sub> · n<sub>Ir</sub><sup>-1</sup>. The resulting W - O-Ir bridging motif proves pivotal for enhancing the efficacy of OER catalysis by facilitating deprotonation of OER intermediates and promoting a thermodynamically favorable dual-site adsorbent evolution mechanism. Besides, the phase selective insertion of W-O in NiIrO<sub>x</sub> enabling charge balance through the W-O-Ir bridging motif, effectively counteracting lattice oxygen loss by regulating Ir-O co-valency.