Catalytic Combustion of Styrene over the Binary Mixture of Manganese and Copper Based Catalyst in the Absence and Presence of Water Vapor

Abstract

MnO x and MnCu based catalysts prepared by ultrasonic impregnation methods were characterized by XRD, TPR-H2, XPS and N2 adsorption and tested for styrene combustion in the presence and absence of water vapor. Results showed that the loading of binary mixtures of manganese oxide and copper oxide on γ-Al2O3 increased the ratio of Cu+/Cu2+ of the defect spinel of Cu1.5Mn1.5O4–x and the reducibility of the catalyst and in this way increased the catalytic activity of the catalysts for styrene combustion. The catalyst MnCu/γ-Al2O3 (20%/l) with 20 wt % loading amount and the Mn/Cu ratio of 1 : 1 showed the highest catalytic activity with T90 = 214°C. Water vapor in feed steam decreased the activity of the catalysts MnCu/γ-Al2O3 (20%/l) and Mn2O3/γ-Al2O3 (10%). The catalyst MnCu/γ-Al2O3 (20%/l) had more resistant to negative influence of water vapor. Upon addition of 2.94 vol % water vapor to the feed stream a 6.5% decrease in styrene conversion was observed whereas for the catalyst Mn2O3/γ-Al2O3 (10%) a 14% reduction in conversion at the same condition was recorded. Higher resistance to the negative influence of water vapor could be due to weaker interactions between water molecules and the surface of catalyst.