A significant boost to the catalytic technology of CO2-to-DME hydrogenation in a single step was recently given by the design of novel hybrid multimetallic/zeolite systems. However, a significant drop of catalyst activity after few hours of operation time pushes now the research interest towards the development of more stable multifunctional systems, suitable to ensure activity, selectivity and lifetime under typical industrial conditions. In this work, the influence of different home-made zeolite samples (i.e., Sil-1, MFI, Y, FER, BEA, MOR), integrated with a CuO-ZnO-ZrO2 metal-oxide(s) phase, was investigated in a fixed bed reactor during CO2 hydrogenation reaction to assess the activity-selectivity pattern of the hybrid catalyst as well as their deactivation trend during operation time. Catalytic results, in terms of CO2 conversion and product distribution in several reaction conditions (TR: 200-260 °C; PR: 3.0 MPa, GHSV: 2,200-8,800 NL/kgcat/h), allowed to ascertain the key features controlling the achievement of high DME yield. Basic structure-activity relationships (see Fig. 1) helped to explain how the extent of interaction between the metal-oxides phase with the zeolite surface as well as the strength of the acid sites play a significant role in the catalyst stability2. In particular, if a suitable acid density is fundamental to drive the process towards the formation of DME, a lower framework density of the zeolite structure, such as in MOR or BEA, is also fundamental to realize a larger interface area with the metal-oxide sites, so leading to more stable catalysts.
Role of zeolites in the direct CO2 hydrogenation to DME
Giuseppe Bonura;S Todaro;C Cannilla;F Frusteri
2021
Abstract
A significant boost to the catalytic technology of CO2-to-DME hydrogenation in a single step was recently given by the design of novel hybrid multimetallic/zeolite systems. However, a significant drop of catalyst activity after few hours of operation time pushes now the research interest towards the development of more stable multifunctional systems, suitable to ensure activity, selectivity and lifetime under typical industrial conditions. In this work, the influence of different home-made zeolite samples (i.e., Sil-1, MFI, Y, FER, BEA, MOR), integrated with a CuO-ZnO-ZrO2 metal-oxide(s) phase, was investigated in a fixed bed reactor during CO2 hydrogenation reaction to assess the activity-selectivity pattern of the hybrid catalyst as well as their deactivation trend during operation time. Catalytic results, in terms of CO2 conversion and product distribution in several reaction conditions (TR: 200-260 °C; PR: 3.0 MPa, GHSV: 2,200-8,800 NL/kgcat/h), allowed to ascertain the key features controlling the achievement of high DME yield. Basic structure-activity relationships (see Fig. 1) helped to explain how the extent of interaction between the metal-oxides phase with the zeolite surface as well as the strength of the acid sites play a significant role in the catalyst stability2. In particular, if a suitable acid density is fundamental to drive the process towards the formation of DME, a lower framework density of the zeolite structure, such as in MOR or BEA, is also fundamental to realize a larger interface area with the metal-oxide sites, so leading to more stable catalysts.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
