气候变化领域集成服务门户

A simple and innovative process is described for the ecofriendly preparation of ceria foams via carboxymethylcellulose gelation by Ce4+ cations; heat treatment of the ensuing xerogels produces ceria foams. The influence of the concentration of cerium and of the calcination temperature of the xerogels is studied. Several characterization methods have been used and the obtained results demonstrate that this technique allows the controlled growth of ceria foams. The foamy structure apparently is responsible for UV absorption, and the ceria foam is basic enough to promote the epoxidation of chalcone; comparison of the catalytic activity of the ceria foam versus ceria prepared via a coprecipitation method shows that the ceria foam is most active as it promotes epoxidation of electron-deficient alkenes with dilute aqueous hydrogen peroxide.