STRUCTURE OF RANEY NICKEL .1. PORE STRUCTURE

Raney nickel alloys were examined by metallographic methods. The alloys were extracted by aqueous sodium hydroxide in several ways and nitrogen isotherms at -195 °C determined. The pore structure of the activated catalyst was relatively independent of phase composition of the original alloy. Significant differences in pore structure were observed between samples extracted at 50 °C and those prepared at the boiling point of the alkali solution, 107 °C. Preparations at 50 °C had a surface area of 110 ± 10 m2/g and a pore volume of 0.07 ± 0.02 cc/g compared with 80 ± 10 m2/g and 0.12 ± 0.02 cc/g for extraction at 107 °C. Both types of samples had a bimodal pore distribution with maxima for pore diameters in range 20-24 Å and 34-48 Å, but 50 °C preparations contained a larger fraction of small pores than the 107 °C samples. Further treatment of the 50 °C preparation with fresh aqueous alkali changed the pore structure to that typical of high-temperature extraction. Data are given for partly extracted catalysts and preparations made with less than the stoichiometric amount of alkali. © 1969.