The role of carbon supports for Ru-based catalysts in ammonia decomposition: A review

Abstract

Ammonia has garnered attention as a desired hydrogen carrier because of its high hydrogen content, ease of storage and transportation, and mature infrastructure. With the growing interest in H₂ utilization, H₂ production by ammonia decomposition has been recognized as a potential approach for a sustainable hydrogen society. There is therefore room for the development of a novel catalyst for low-temperature and highly efficient ammonia decomposition. Ru is considered the most active metal because of its strong interaction with nitrogen atoms. To achieve efficient ammonia decomposition, Ru-based catalysts have been investigated using various types of supports and promoters to modify the electronic and structural properties of Ru. Carbon materials, such as carbon nanotubes, carbon nanofibers, and graphene, have a high surface area, offering high Ru dispersion, which results in the formation of active sites for ammonia decomposition. Furthermore, recent research has speculated that carbon materials with highly graphitic structures, good electroconductivity, and nitrogen doping can improve the catalytic performance of the resulting Ru-based catalysts in ammonia decomposition by electron transfer from the carbon to the Ru.