Efficient Low-temperature Ammonia Cracking Enabled by Strained Heterostructure Interfaces on Ru-free Catalyst.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40289842.
- Also identified by DOI 10.1002/adma.202502034 and PMC identifier 12676095.
- 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
Ammonia (NH<sub>3</sub>) has emerged as a promising liquid carrier for hydrogen (H<sub>2</sub>) storage. However, its widespread adoption in H<sub>2</sub> technology is impeded by the reliance on costly Ru catalysts for low-temperature NH<sub>3</sub> cracking reaction. Here, a strained heterostructure Co@BaAl<sub>2</sub>O<sub>4-x</sub> core@shell catalyst is reported that demonstrates catalytic performance at low reaction temperatures comparable to most Ru-based catalysts. This catalyst exhibits exceptional activity across a range of space velocity conditions, maintaining high conversion rates at 475 to 575 °C and achieving an impressive H<sub>2</sub> production rate of 64.6 mmol H<sub>2</sub> g<sub>cat</sub> <sup>-1</sup> min<sup>-1</sup>. Synchrotron X-ray absorption spectroscopy, synchrotron X-ray diffraction, and kinetic studies are carried out to elucidate the dynamic changes of the strained heterostructure interface of Co-core and BaAl<sub>2</sub>O<sub>4-x</sub>-overlayer under catalytic working conditions. The performance enhancement mechanisms are attributed to the tensile strained Co surface encapsulated in the defective BaAl<sub>2</sub>O<sub>4-x</sub>, which enhances NH<sub>3</sub> adsorption and facilitates the rate-determining N─H dissociation. Furthermore, the strain release and restoration during NH<sub>3</sub> dehydrogenation enable efficient nitrogen desorption, preventing active site poisoning. This work highlights the effectiveness of lattice strain engineering and the development of synergistic strong metal-support interfaces between active metal nanoparticles and oxide support to boost low-temperature NH<sub>3</sub> cracking.