Atomically dispersed Iridium on Mo<sub>2</sub>C as an efficient and stable alkaline hydrogen oxidation reaction catalyst.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38762595.
- Also identified by DOI 10.1038/s41467-024-48672-9 and PMC identifier 11102501.
- 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
Hydroxide exchange membrane fuel cells (HEMFCs) have the advantages of using cost-effective materials, but hindered by the sluggish anodic hydrogen oxidation reaction (HOR) kinetics. Here, we report an atomically dispersed Ir on Mo<sub>2</sub>C nanoparticles supported on carbon (Ir<sub>SA</sub>-Mo<sub>2</sub>C/C) as highly active and stable HOR catalysts. The specific exchange current density of Ir<sub>SA</sub>-Mo<sub>2</sub>C/C is 4.1 mA cm<sup>-2</sup><sub>ECSA</sub>, which is 10 times that of Ir/C. Negligible decay is observed after 30,000-cycle accelerated stability test. Theoretical calculations suggest the high HOR activity is attributed to the unique Mo<sub>2</sub>C substrate, which makes the Ir sites with optimized H binding and also provides enhanced OH binding sites. By using a low loading (0.05 mg<sub>Ir</sub> cm<sup>-2</sup>) of Ir<sub>SA</sub>-Mo<sub>2</sub>C/C as anode, the fabricated HEMFC can deliver a high peak power density of 1.64 W cm<sup>-2</sup>. This work illustrates that atomically dispersed precious metal on carbides may be a promising strategy for high performance HEMFCs.