Preparation of cobalt-copper-aluminum spinel mixed oxides from layered double hydroxides for total oxidation of benzene

Mixed metal oxides Co 5 − x Cu x Al ( x = 0–0.5) were prepared from Co-Cu-Al layered double hydroxides (LDHs) and tested for benzene total oxidation. By calcination, Co-Cu-Al LDHs were mainly transformed to (Co, Cu)(Co, Al) 2 O 4 spinels, where both Cu 2 + and Al 3 + cations were incorporated into the spinel structure. The incorporation of Cu significantly improved the Co oxide reducibility and remarkably enhanced the light-off activity as well as the total conversion activity, indicative a strong interaction between Cu 2 + and Co 3 + active sites. The optimum Co 4.75 Cu 0.25 Al spinel mixed oxide was comparable with a 0.3%Pd/γ-Al 2 O 3 catalyst, highlighting the promoting effect of structural modification with Cu.