Synergistic Effect of Copper and Cobalt in Cu-Co Bulk Oxide Catalyst for Catalytic Oxidation of Volatile Organic Compounds

Abstract

In this paper, transition metal oxide bulk catalysts were prepared with the precipitation method, to investigate their activity for the catalytic oxidation of VOCs (model VOCs: toluene and ethyl acetate), with an aim to develop a low-priced, safe and high-effective substitute catalyst for the noble metal-based catalysts. A synergistic effect of cooper and cobalt was observed over the Cu-Co oxide catalysts, which showed higher activity than copper oxide or cobalt oxide. In the Cu-Co catalyst, it is considered that the fine dispersion of CuO particles on the surface of Co₃O₄, especially the formation of Cu-Co spinel, probably causes an increase in the BET surface area, and eventually enhances the VOCs oxidation activity. When the 31 wt% Cu-44 wt% Co catalyst was subjected to the toluene catalytic oxidation, it gave a complete oxidation temperature of 200°C, similar to a commercial 0.5 wt% Pt/Al₂O₃. In the ethyl acetate catalytic oxidation, a dramatic activity was exhibited, and the complete conversion temperature of 175°C obtained over the 31 wt% Cu-44% Co catalyst was far lower than that of 0.5 wt% Pt/Al₂O₃ (ca. 300°C).