Synthesis and characterization of γ-alumina supported cobalt and iron nanocatalysts

The present work deals with the synthesis of cobalt monometallic and bimetallic Co/Fe nanocatalysts supported on alumina. The nanocatalysts were prepared by wet impregnation method. The samples were characterized in terms of reducibility, dispersion, metal particle size, textural characteristics and crystallinity. These characteristics were revealed by using Temperature Programmed Reduction (TPR), CO-Chemisorption, Transmission Electron Microscopy (TEM), X-Ray Diffraction Spectroscopy (XRD) and BET-surface area analysis. H2-TPR analysis of Co/Al2O3 indicated three temperature regions at 507 ◦C (low temperature), 650 ◦C (medium temperature) and 731 ◦C (high temperature) while characteristic peaks of Fe/ Al2O3 appeared at 454 ◦C, 635 ◦C and 716 ◦C, respectively. Bimetallic nanocatalysts exhibited different physicochemical properties than those of the monometallic nanocatalysts. The incorporation of iron into cobalt nanocatalysts up to 50% of the total metal loaded enhanced the reducibility, increased the CO and H2 chemisorbed and degree of reduction (DRT) while surface area decreased, further increase in the iron content resulted in a decrease in the crystallinity, increase in the average metal particle size and shift in the reduction towards higher temperatures.