Evaluation of regenerative function and activity for reforming tar of composite oxide catalysts containing spinel structure

Regenerative function of composite catalysts containing NiAl2O4 spinel (NAO) were examined by temperature programmed reduction and analysis of crystalline structure. It was confirmed that, when NAO was reduced by H2 at about 800 °C, fine Ni particles precipitated from NiAl2O4 and became highly dispersed on γ-Al2O3, and conversely when it was oxidized, the precipitated Ni particles dissolved into γ-Al2O3 forming NiAl2O4. Furthermore, NAO added with Ru (RNAO) increased the amount of regenerating NiAl2O4 and reduction rate at lower temperature than NAO. By evaluating the reforming activity of toluene with RNAO, NAO and Pt/γ-Al2O3 based on kinetics and thermodynamics, reduced RNAO and NAO showed from 1.5 to 3.0 times higher activity than the conventional Pt/γ-Al2O3. Additionally, the activity of RNAO did not decrease after several times regeneration.