Thermal and FrIR studies on Cu/Si-Al by sol-gel and Cu/zeolite catalysts are compared by determining the effect of alumina and Cu incorporation into a SiO2-Al2O3 and zeolite base support matrix. Hydroxyl groups formed during hydrolysis are more stable as the amount of alumina increases in the matrix. A proposed mechanism for metal incorporation involving the effect of alumina incorporation into the matrix is presented. This mechanism may explain the formation of different Cu-based structures.