Adsorption of 2-chlorophenol on the surface of silica- and alumina-supported iron oxide: an FTIR and XPS study

The adsorption of 2‐chlorophenol (2‐CPh) on the surface of silica, alumina and silica‐ and alumina‐supported iron oxides was examined at 30 and 250 °C. The formation of a chlorophenolate carbanion/chlorophenoxy radical intermediate on the surface of silica and alumina surfaces is identified by using in situ FTIR spectroscopy. The IR spectra of 2‐CPh adsorbed on supported iron oxide at 250 °C highlight significant differences in the adsorption complex between 2‐CPh and the two supported iron oxides (on silica and alumina). Under conditions of the low coverage of 2‐CPh on the surface of these catalysts, FTIR spectroscopy was used to indicate that the adsorption of 2‐CPh on the surface of silica‐supported iron oxide commences with the formation of a chlorophenolate species, whereas 2‐CPh creates a surface formate species on alumina‐supported iron oxide. Moreover, the strong bonds of 2‐CPh and a high concentration of the carbonate species are evident on the alumina surfaces by using both FTIR and X‐ray photoelectron spectroscopy.