Preparation, characterization and kinetic behavior of supported copper oxide catalysts on almond shell-based activated carbon for oxidation of toluene in air

Dispersed copper oxide nano-catalysts supported on almond shell-based activated carbon were prepared for catalytic oxidation of toluene in air. The response surface methodology was used to express the catalyst removal efficiency in terms of catalyst metal loading and calcination temperature. Catalyst activity increased with both increasing calcination temperature and metal loading. Calcination temperature had a significant effect on the catalyst activity only at high metal loadings. Two different catalyst preparation methods were employed to investigate the effect of impregnation technique on the deposition–precipitation method. Well-dispersed nano catalysts with higher efficiency towards oxidation of toluene were prepared by the heterogeneous deposition–precipitation (HDP) as compared with the combined impregnation and deposition–precipitation method. The support and catalyst properties were determined by X-ray diffraction, Transmission electron microscopy, field-emission scanning electron microscope, Boehm test, Brunauer–Emmett–Teller surface area measurements, and energy-dispersive X-ray spectroscopy. Characterization analyses and reaction experiments indicated the antonym effect of impregnation method on the deposition–precipitation method for catalyst preparation. Two types of crystallite (large and small) were formed on the support as a consequence of using the combined catalyst preparation method. Kinetic models were proposed for oxidation of toluene using copper oxide catalysts prepared by the HDP method. The kinetic study indicated that an Eley–Rideal mechanism could adequately describe the kinetic behavior of toluene oxidation.