| abstract |
PURPOSE: To provide a catalyst functioning even at a low temp., highly active, and easily regenerated by subjecting an Ni- and/or Co-base amorphous alloy containing specific amounts of Nb and/or Ta and platinum metal to activating treatment by means of immersion in hydrofluoric acid. n CONSTITUTION: This amorphous alloy catalyst for exhaust gas cleaning is obtained by applying hydrofluoric acid treatment to an amorphous alloy having a composition consisting of, by atom, 20-70% Nb and/or Ta, 0.5-20% of one or more elements among Ru, Pd, Rh, Pt, and Ir, and the balance Ni and/or Co. Although the concentration of the platinum group elements is extremely low, this catalyst produces high catalytic activity and can clean exhaust gases even at a temp. in the vicinity of ordinary temp. The amount of the platinum group elements is regulated to a value in the above range because the addition of the platinum group elements in large quantities causes not only increase in costs but also reduction in the action of dissolving unnecessary elements at the time of hydrofluoric acid treatment and, as a result, the surface concentration of the platinum group elements as well as the increase in surface area by means of hydrofluoric acid treatment are made difficult. n COPYRIGHT: (C)1991,JPO&Japio |