Hydrothermal tolerance towards different temperature conditions over two typical Cu/CHA catalysts

Abstract

• Low and high temperature hydrothermal stability of Cu/SAPO-34 and Cu/SSZ-13 are studied. • Both low and high temperature aging decrease catalytic property of Cu/SAPO-34. • Al-rich CuO x clusters, aggregated CuO x clusters, and AlPO 4 species are found over aged Cu/SAPO-34. • High temperature aging leads to significant performance decline of Cu/SSZ-13. • High temperature aged Cu/SSZ-13 exhibits severe lack of active sites and structural degradation. This research focused on the hydrothermal tolerance of Cu/SAPO-34 and Cu/SSZ-13 catalysts. Either low- or high-temperature aging decreases the catalytic property of Cu/SAPO-34. Cu/SAPO-34 lost some isolated copper sites, and new copper-aluminum complexes CuAl 2 O 4 and Al-rich CuO x clusters formed after low temperature aging. High temperature aging resulted in CuO x clusters and AlPO 4 species formed, which led to the loss of Cu 2+ active sites and surface nitrates adsorbed sites over Cu/SAPO-34. Cu/SSZ-13 retained the catalytic performance after low temperature aging but was totally intolerant to high temperature aging. High temperature hydrothermal aging led to the loss of active sites, lack of surface nitrates adsorbed sites, and serious structural degradation over Cu/SSZ-13.