A series of Ga-substituted hydrotalcite-like materials (GaHTs), [Mg 1-x Ga x (OH) 2 ](CO 3 ) x/2 ‚mH 2 O where x ) 0.12-0.36, were prepared in order to examine their textural and basic properties upon different Mg/Ga contents and calcination temperature. Specific surface area increases from 46 to 156 m 2 g -1 (Mg/Ga ) 7.7) when calcining from 523 to 673 K as a consequence of dehydroxylation and decarbonation of the material. The total number of base sites increases upon higher calcination temperatures until reaching a maximum at 873 K and then decreases. CO 2 thermal programmed desorption indicates that different Mg/Ga relative contents have a considerable effect on the amount of base sites. For instance, a GaHT with Mg/Ga ) 7.7 exhibits 2.4 times more total base sites than that of Mg/Ga ) 2.9. Additionally, in the former, the generation of medium and strong base sites is considerably higher than in the latter. By means of CDCl 3 adsorption and FTIR, several types of base sites were identified. The base sites strength (pK a ) -1 to +19) and proton affinity (815-987 kJ mol -1 ) values were estimated considering the ν CD shift of adsorbed CDCl 3 and correlating it with the pK a of bases that form hydrogen-bonded complexes.
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