In-situ IR study for elucidating the adsorption cracking mechanism of toluene over calcined olivine catalyst

In order to improve the energy conversion efficiency of hydrogen production from biomass gasification and reduce environmental pollution, it is necessary to study the mechanism of tar catalytic cracking. In present work, in-situ infrared spectroscopy has been used to study the adsorption cracking of toluene on calcined olivine catalyst from room temperature to 500 °C. The experimental results indicate that there is no chemical adsorption of toluene on calcined olivine catalyst from room temperature to 200 °C. When the temperature is higher than about 300 °C, the toluene is chemically adsorbed on α-Fe2O3, which is the surface active site of the calcined olivine catalyst. The chemical adsorption occurs between the benzene ring and Fe3+, and it promotes the breakage of methyl from the benzene ring. With the increasing of reaction temperature, the delocalization large π bond in the benzene ring is destroyed by Fe3+, which makes the benzene ring easier to break into smaller products or intermediate products.