ADSORPTION OF NICKELTETRACARBONYL ON ZEOLITES STUDIED BY INFRARED-SPECTROSCOPY

Ni(CO)(4) is adsorbed on wide pore X and Y zeolites inside the pores o f the zeolites and shows a set of strong bands between 2,150 and 1,950 cm(-1). Only one kind of adsorbed Ni(CO)(4) exists on NaX zeolite, wh ereas two species of adsorbed Ni(CO)(4) with C-2v and C-3v symmetry ex ist on NaY and NaHY zeolites. The concentration ratio of both carbonyl s depends on the Na+/H+ C exchange ratio. Ni(CO)(4) is physisorbed on narrow pore A and ZSM-5 zeolites on the outer surface producing a smal l band at 2,058 cm(-1) with a shoulder at 2,040 cm(-1). The appearance of some other small bands individual for each sample suggests an adso rption on structural defects and a partial decomposition of the carbon yl.