Balancing hydrogen adsorption/desorption by orbital modulation for efficient hydrogen evolution catalysis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31492875.
- Also identified by DOI 10.1038/s41467-019-12012-z and PMC identifier 6731251.
- 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
Hydrogen adsorption/desorption behavior plays a key role in hydrogen evolution reaction (HER) catalysis. The HER reaction rate is a trade-off between hydrogen adsorption and desorption on the catalyst surface. Herein, we report the rational balancing of hydrogen adsorption/desorption by orbital modulation using introduced environmental electronegative carbon/nitrogen (C/N) atoms. Theoretical calculations reveal that the empty d orbitals of iridium (Ir) sites can be reduced by interactions between the environmental electronegative C/N and Ir atoms. This balances the hydrogen adsorption/desorption around the Ir sites, accelerating the related HER process. Remarkably, by anchoring a small amount of Ir nanoparticles (7.16 wt%) in nitrogenated carbon matrixes, the resulting catalyst exhibits significantly enhanced HER performance. This includs the smallest reported overpotential at 10 mA cm<sup>-2</sup> (4.5 mV), the highest mass activity at 10 mV (1.12 A mg<sub>Ir</sub><sup>-1</sup>) and turnover frequency at 25 mV (4.21 H<sub>2</sub> s<sup>-1</sup>) by far, outperforming Ir nanoparticles and commercial Pt/C.