Study of oxygen-binding cobalt species on CoAPO-11 molecular sieve under redox treatment

Abstract

Under oxygen adsorption, a cobalt–O₂ species with an O–O band at 1019 cm⁻¹ and a paramagnetic superoxo–cobalt(Co–O–O) species with O–O and Co–O bands at 1048 and 467 cm⁻¹ have been observed on calcined and reduced CoAPO-11molecular sieve samples, respectively, by Raman spectroscopy. The stretching modes of superoxo–cobalt have also beenconfirmed by ¹⁶O₂/¹⁸O₂ substitution.