Electrical and Structural Properties and Facile Synthesis of Alumina Modified by Metal Nanoparticles

Abstract: Alumina catalysts modified by platinum and nickel nanoparticles were prepared by chemical reduction and microwave stimulated techniques, and their relationship to electrical properties was studied. The structural and textural properties of such nanocatalysts were examined by XRD, DSC-TGA, N₂ physisorption and TEM. The electrical properties of nanoparticle catalysts as functions of the increase of metal concentration are discussed. The electrical measurements were performed in the frequency domain. Three mechanisms are suggested for the electrical behaviour of all systems. The increment observed in conductivity with extra amounts of metal may be due to the expansion in the movement ability of uncontrolled transporters that disperse in the pores of the material. Upon arrival at the electrodes, these transporters evacuate their charge and, accordingly, increase the dispersion impedance. The results show high thermal stability up to 1000 ^°C. The isotherms obtained display almost the same behaviour for samples prepared by both the microwave and the chemical method. This may be linked to high-dispersion particles and their nanoscale metal concentration. The XRD results exhibit small diffraction line characteristics.