Nitrosyl complexes on Co–ZSM-5: an FTIR spectroscopic study

Adsorption of NO on Co–ZSM-5 results in formation of three kinds of Co3+–NO species (1970, 1957 and 1940 cm−1) and Co2+(NO)2 dinitrosyls (1894 and 1811 cm−1). All these species disappear after evacuation at elevated temperatures. However, a very short evacuation of the sample with preadsorbed NO at 673 K, followed by quenching to room temperature, results in appearance of a band at 1857 cm−1. This band is assigned to Co2+–NO linear species produced after partial destruction of the dinitrosyls. The reasons for the different pathways of the dinitrosyl decomposition are discussed.