The structural effect of Ni/ZrO2 on the formation and the reactivity of the carbon formed from methane decomposition

In this work, the structural effect of the plasma decomposed Ni/ZrO2 catalyst and the thermally calcined Ni/ZrO2 catalyst on the formation and the reactivity of the carbon formed from methane decomposition was investigated. The plasma prepared Ni/ZrO2 catalyst possesses smaller Ni particle size with Ni (1 1 1) as the principally exposed facet, which favors the formation of the carbon with enhanced reactivity towards carbon dioxide. The Ni (1 1 1) facet benefits the formation of carbon nanotubes (CNTs) attached to Ni nanoparticles at the top and suppresses the formation of onion-like carbon which encapsulates Ni active sites. Besides, CNTs on the plasma-treated catalyst show smaller diameter sizes with lower graphitization degree, which are easier to be converted. Therefore, the plasma prepared catalyst presents a higher carbon resistance. The present work well explains the improved activity and stability of the plasma prepared Ni/ZrO2 catalyst for CO2 reforming of methane.