The generation of 6 wt. % potassium-modified alumina (K-A1,03) from K,CO,-impregnated alumina (AI , O, / K, CO, ) has been explored by means of surface and bulk analytical techniques, so as to characterize the interfacial synthetic events involved in the various preparative steps, namely: (i) wet impregnation, (ii) the drying process and (iii) high-temperature calcination. K+(aq) adsorption measurements indicated that 50% of the potassium content in the impregnating solution is loaded onto AI , O, via, essentially, a specific adsorption mechanism, involving a type of cation exchange with isolated AI-OH groups and formation of chemically bound AI-OK surface groups. ln situ infrared spectroscopic observations supported the adsorption measurements, revealing that after the impregnated material had been dried at 393 K, most of the isolated AI-OH groups are eliminated and, simultaneously, KAI(CO,)(OH,)-like surface species are formed. Calcination products up to 1273 K were examined using ex situ X-ray diffraction and photoelectron spectroscopy. The high-temperature treatment was found to activate various solid/solid interfacial interactions leading to low-temperature decomposition of surface carbonate and hydroxy groups, and formation of highly dispersed K-AI,O,.The results further indicate that the presence of K+ ions has no significant bearing on the accessible area of the alumina and on the thermal stability and structure of the bulk.

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