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  Dreyer, M.; Cruz, D.; Hagemann, U.; Zeller, P.; Heidelmann, M.; Salamon, S.; Landers, J.; Rabe, A.; Ortega, K.F.; Najafishirtari, S.; Wende, H.; Hartmann, N.; Knop-Gericke, A.; Schlögl, R.; Behrens, M.: The Effect of Water on the 2-Propanol Oxidation Activity of Co-Substituted LaFe_1-xCo_xO₃ Perovskites. Chemistry - A European Journal 27 (2021), p. 17127-17144

10.1002/chem.202102791
Open Access Version (externer Anbieter)

Abstract:
Perovskites are interesting oxidation catalysts due to their chemical flexibility enabling the tuning of several properties. In this work, we synthesized LaFe1-xCoxO3 catalysts by co-precipitation and thermal decomposition, characterized them thoroughly and studied their 2-propanol oxidation activity under dry and wet conditions to bridge the knowledge gap between gas and liquid phase reactions. Transient tests showed a highly active, unstable low-temperature (LT) reaction channel in conversion profiles and a stable, less-active high-temperature (HT) channel. Cobalt incorporation had a positive effect on the activity. The effect of water was negative on the LT channel, whereas the HT channel activity was boosted for x>0.15. The boost may originate from a slower deactivation rate of the Co3+ sites under wet conditions and a higher amount of hydroxide species on the surface comparing wet to dry feeds. Water addition resulted in a slower deactivation for Co-rich catalysts and higher activity in the HT channel state.