Analysis of catalytic oxidation of aromatic hydrocarbons over supported palladium catalyst with different pretreatments based on heterogeneous adsorption properties

We investigated the catalytic oxidation and adsorption of benzene, toluene, and o-xylene (BTX) by using the palladium (Pd)-based catalyst and its pretreated (pre-oxidized and pre-reduced) catalysts. The physico-chemical properties of the catalysts were characterized and confirmed by using several reliable methods such as the Brunauer Emmett Teller (BET) surface area analysis, gravimetric adsorption analysis, light-off curves analysis, and X-ray photoelectron spectroscopy (XPS). The adsorption and catalytic activities of the catalysts were found to be closely connected with the pretreatment methods and temperatures. Especially, the hydrogen treated catalysts with a largely metallic form enhanced the adsorption ability and catalytic activity of toluene compared to that of the parent and air treated catalysts. In addition, the adsorption equilibrium isotherms of BTX on pre-reduced catalyst at three different temperatures were analyzed successfully with the two sites localized Langmuir (L2m) isotherm equation. Moreover, the strong correlations between the catalytic behavior and the adsorption properties of BTX were explained in terms of adsorption affinity, isosteric heat of adsorption, and adsorption energy distributions.

The influence of pretreatments (air and hydrogen) on the Pd based catalyst for the adsorption and catalytic oxidation of different aromatic hydrocarbons (BTX) were investigated. The strong correlation between the catalytic oxidation and the adsorption was explained in terms of adsorption affinity, isosteric heat of adsorption, and adsorption energy distribution.Figure optionsDownload as PowerPoint slide