Efficient Low‐temperature Ammonia Cracking Enabled by Strained Heterostructure Interfaces on Ru‐free Catalyst
Pei Xiong, Jiangtong Li, Zhihang Xu, Yashan Lin, Robert D. Bennett, Yi Zhang, Wen‐Jun Tu, Ye Zhu, Y. L. Soo, Tai‐Sing Wu, Molly Meng‐Jung Li
Abstract
Abstract Ammonia (NH 3 ) has emerged as a promising liquid carrier for hydrogen (H 2 ) storage. However, its widespread adoption in H 2 technology is impeded by the reliance on costly Ru catalysts for low‐temperature NH 3 cracking reaction. Here, a strained heterostructure Co@BaAl 2 O 4−x 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 2 production rate of 64.6 mmol H 2 g cat −1 min −1 . 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 2 O 4−x ‐overlayer under catalytic working conditions. The performance enhancement mechanisms are attributed to the tensile strained Co surface encapsulated in the defective BaAl 2 O 4−x , which enhances NH 3 adsorption and facilitates the rate‐determining N─H dissociation. Furthermore, the strain release and restoration during NH 3 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 3 cracking.