| Popis: |
Hydrogen reduction of tubular nickel and nickel magnesium chrysotiles in a microbalance produced high Ni surface areas (10–30 m2/g) and uniform size distributions centered about 3 nm at 250 °C and increasing to a mean of 8 nm at 550 °C. The areas, measured by O2 chemisorption, were higher at the higher temperatures due to more complete reduction, which was difficult in a single step, especially with Mg present. High temperature reduction and reoxidation, followed by a second reduction at 350–450 °C, raised the Ni areas to 35–50 m2/g. Reduction of a high area, flake-type nickel chrysotile gave much lower Ni areas (2–7 m2/g) and mean Ni crystallite diameters greater than 20 nm. |
