Reactivity of Aluminum Clusters with Water and Alcohols: Competition and Catalysis?

An in-depth investigation is presented on the hydrogen evolution reaction of aluminum clusters with water and methanol/isopropanol. Aluminum clusters were found to undertake an etching effect in the presence of methanol, but also resulted in an addition reaction with isopropanol. Such reactivity without producing hydrogen is different than water, although they all contain an OH group. Further, we studied the competition of water versus alcohols reacting with Al clusters by simultaneously introducing them into a fast-flow tube reactor. Water dominates the competitive reaction with Al clusters, and the O-H bond in water is readily activated to form aluminum hydroxide cluster products. Also found is that water functions as a catalyst in the activation of the O-H bond in alcohol molecules.