Abstract
The physicochemical, surface and catalytic properties of pure and doped CuO/MgO solids with La
2O
3 and ZrO
2 prepared by sol–gel method followed by calcination at 350, 500 and 650
°C were investigated. The dopant concentrations of La
2O
3 and ZrO
2 were 2.0, 4.0, 6.0 and 8.0
mol%. The amounts of CuO loaded were 0.1, 0.2 and 0.3
mol. The techniques employed were XRD, FTIR, nitrogen adsorption at −196
°C, CO oxidation by O
2 at 225–275
°C and H
2O
2 decomposition in aqueous solution at 30–50
°C.
The results obtained revealed that the doping of CuO/MgO solids with different amounts of La
2O
3 and ZrO
2 brought about a progressive decrease in the degree of crystallinity of CuO and MgO phases and their particle size. The doping of CuO/MgO solid catalysts with La
2O
3 led to a progressive decrease in their specific surface areas, while the doping with ZrO
2 exerted opposite effect. The doping process with La
2O
3 and ZrO
2 brought about a progressive increase in the catalytic activities of the investigated solid catalysts towards CO oxidation by O
2 to an extent proportional to the amount of dopant added. The doping of solid catalysts with La
2O
3 led to a decrease in their catalytic activities towards H
2O
2 decomposition, while the doping with ZrO
2 led to an increase in the catalytic activity of the investigated solids calcined at different temperatures. The increase in the copper content of loading led to a decrease in the specific surface areas of solid catalysts, while for catalysis the increase of copper content resulted in a progressive increase in their catalytic activities towards CO oxidation for solids calcined at different temperatures and towards H
2O
2 for solids calcined at 350 and 500
°C. The doping process led to an increase in the concentration of catalytically active constituents on the catalyst surface taking part in the catalytic process.