Spin occupancy regulation of the Pt d-orbital for a robust low-Pt catalyst towards oxygen reduction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39013873.
- Also identified by DOI 10.1038/s41467-024-50332-x and PMC identifier 11252259.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Disentangling the limitations of O-O bond activation and OH* site-blocking effects on Pt sites is key to improving the intrinsic activity and stability of low-Pt catalysts for the oxygen reduction reaction (ORR). Herein, we integrate of PtFe alloy nanocrystals on a single-atom Fe-N-C substrate (PtFe@Fe<sub>SAs</sub>-N-C) and further construct a ferromagnetic platform to investigate the regulation behavior of the spin occupancy state of the Pt d-orbital in the ORR. PtFe@Fe<sub>SAs</sub>-N-C delivers a mass activity of 0.75 A mg<sub>Pt</sub><sup>-1</sup> at 0.9 V and a peak power density of 1240 mW cm<sup>-2</sup> in the fuel-cell, outperforming the commercial Pt/C catalyst, and a mass activity retention of 97%, with no noticeable current drop at 0.6 V for more than 220 h, is attained. Operando spectroelectrochemistry decodes the orbital interaction mechanism between the active center and reaction intermediates. The Pt dz<sup>2</sup> orbital occupation state is regulated to t<sub>2g</sub><sup>6</sup>e<sub>g</sub><sup>3</sup> by spin-charge injection, suppressing the OH* site-blocking effect and effectively inhibiting H<sub>2</sub>O<sub>2</sub> production. This work provides valuable insights into designing high-performance and low-Pt catalysts via spintronics-level engineering.