Cobalt Species Active for Nitrous Oxide (N₂O) Decomposition within a Temperature Range of 300-600°C

This article presents a novel study of the role of the catalyst support towards the formation of active cobalt sites for N2O conversion reactions within a temperature range of 300-600°C. These reactions were examined in a fixed bed tubular reactor. ZSM-5 (Si/Al≤15), TS-1, and amorphous silicates were used as catalyst supports for cobalt loadings. All catalysts were prepared by following standard methods and recipes. In general, cobalt loading on supports was varied between 0.78 and 5.40wt.-% (as determined from inductively coupled plasma (ICP) analysis). ICP, temperature programmed desorption, X-ray diffraction, and N2 adsorption/desorption isotherms were used for the characterization of prepared catalysts. Cobalt on ZSM-5 support generates weak and strong acid sites. Furthermore, for the Co-ZSM-5 catalyst, prepared by a wet deposition method, the N₂O decomposition reaction is first order with an activation energy of ∼132kJmol-1. Co₂+ and Co₃+ are the suggested active species for the N2O conversions in the studied range of temperatures.