THE INFLUENCE OF ANNEALING CONDITIONS FOR ALUMINUM-NICKEL-MOLYBDENUM CATALYSTS ON THE COMPOSITION AND DISTRIBUTION OF ACTIVE COMPONENTS

It was shown by Raman spectroscopy that, in the case of long annealing with a slow temperature rise, molybdenum compounds exist in the alumi num-nickel-molybdenum catalyst as surface polycompounds and a crystall ine phase alpha-NiMoO4. They are arranged mainly in the near-surface l ayer (''crust''). An increase in the annealing temperature results in the migration of the molybdenum component to the edges of a granule. F ast heating and a short annealing time result in some shift of the max imum of the molybdenum distribution inside the granule, and surface mo lybdate structures and a disordered beta-phase of nickel molybdate, st abilized by aluminum atoms, become the main compounds.