Effect of Calcination Temperature on NO–CO Decomposition by Pd Catalyst Nanoparticles Supported on Alumina Nanofibers

In this work, palladium (Pd) nanoparticles were blended into a solution of a sacrificial polymer and an aluminum sol gel precursor to form alumina fibers containing the palladium particles. The polymer solution was electrospun into template submicron fibers. These fibers were calcined at temperatures between 650 °C and 1150 °C to remove the polymer and oxidize the aluminum. The internal crystalline morphologies of the calcined fibers transformed with change in the calcination temperature. The calcined fibers were formed into fibrous mats and further tested for their catalytic performances. The Pd particles had a size ranging from 5–20 nm and appeared randomly distributed within and near the surfaces of the alumina fibers. The final metal loading of all Pd/Al2O3 samples ranged from 4.7 wt % to 5.1 wt %. As calcination temperature increased the alumina crystal structure changed from amorphous at 650 °C to alpha crystal structure at 1150 °C. With the increase of calcination temperature, the average fiber diameters and specific surface areas decreased. The catalyst supported fiber media had good conversion of NO and CO gases. Higher calcination temperatures led to higher reaction temperatures from 250 to about 450 °C for total conversion, indicating the effective reactivity of the fiber-supported catalysts decreased with increase in calcination temperature. The fibers formed at the 650 °C calcination temperature had the highest reaction activity.