Modification of Ni state to promote the stability of Ni–Al2O3 catalyst in methane decomposition to produce hydrogen and carbon nanofibers

The methodology was illustrated for modifying the state of Ni to promote the stability of the coprecipitated Ni–Al2O3 catalyst via incorporating ZnO and Cu in methane decomposition to produce hydrogen and carbon nanofibers. The influences of the incorporation on the state of Ni were examined with XRD, TPR, XPS and TEM. For the incorporation of ZnO, ZnAl2O4 spinel-like structure could be formed in the interface between ZnO and Al2O3. The interaction between Ni and the ZnAl2O4 structure can promote both the activity and the stability of Ni in methane decomposition. The formation of a Ni–Cu alloy from Ni and the incorporated Cu decreases the activity of Ni, however, promotes the stability pronouncedly.