H2 formation by electron irradiation of SBA-15 materials and the effect of CuII grafting

Abstract

Measurement of H₂ production from electron irradiation (10 MeV) on SBA-15 materials has shown that adsorbed water is attacked preferentially. Silanol groups are only attacked when they are in the majority with respect to adsorbed water, however they are much less efficient at producing H₂. The comparison between water content before and after electron irradiation and the corresponding H₂ production indicates that water desorption is the main route to adsorbed water loss for SBA-15 materials. On the other hand, surface silanol groups are more susceptible to attack, leading to H₂ production when SBA-15 samples have undergone extensive thermal treatment. Electron irradiation of SBA-15-Cu materials has shown that the presence of Cu^II on the surface reduces and inhibits the production of H_2. This inhibiting power affects adsorbed water bonded to grafted copper but not surface silanol groups.