Reactivity of mesoporous carbon against water - An in-situ XPS study

Functionalized mesoporous carbon catalysts can be used in the acid catalyzed dehydration of fructose to 5-hydroxymethyl furfural (HMF). However, strong deactivation can be observed after preconditioning of the material in the reaction solvent 2-butanol. Surface changes caused by the pretreatment have been studied by XPS. The comparison of the pristine sample and the pretreated carbon sample showed similar distribution of oxygen functional groups by ex-situ XPS, as well as similar behavior during heating in vacuum. However, the addition of water (0.1 mbar vapor pressure) and subsequent heating to 130 °C exhibited prominent differences in the evolution of the O1s, as well as for the C1s spectra of the two samples. Changes in the surface termination and hydrophobicity of the materials are discussed under the aspect of possible reactions of surface functional groups with the alcoholic solvent and water.