Acidity control of zeolite functionality on activity and stability of hybrid catalysts during DME production via CO2 hydrogenation

• Published in: Journal of CO2 utilization Vol. 24; pp. 398 - 406
• Main Authors: Bonura, G., Migliori, M., Frusteri, L., Cannilla, C., Catizzone, E., Giordano, G., Frusteri, F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2018
• Subjects: Catalysts; CO2; Cu-ZnO-ZrO2; Dimethyl ether; Ferrierite; Hydrogenation; Ferrierite; Dimethyl ether; Catalysts; Cu-ZnO-ZrO2; Hydrogenation; CO2
• ISSN: 2212-9820; 2212-9839
• DOI: 10.1016/j.jcou.2018.01.028

•The direct CO2-to-DME hydrogenation was performed with CuZnZr/FER hybrid catalysts.•Ferrierite samples of different acidity and grain size were embedded in catalyst composition.•Water formation was claimed as responsible for the progressive decay of activity over time.•The density of Brønsted acid sites induces a significant metal sintering on copper particles.•The size of the ferrierite grains plays a crucial role on the catalytic behaviour. The catalytic behaviour of a CuZnZr-FER hybrid catalyst was assessed in the direct CO2-to-DME hydrogenation reaction, considering the effects of structural and surface properties induced on the system by homemade ferrierite samples at different acidity and grain size. Notwithstanding a comparable initial activity under the adopted experimental conditions (TR = 220–260 °C; PR = 3.0 MPa; GHSV = 8800 NL/kgcat/h), the investigated catalyst samples exhibited a different behaviour in terms of stability, with a progressive decay with time mostly marked on the hybrid containing ferrierite at larger acidity. Irrespective of the zeolite grain size, TEM analysis showed a low tendency of catalysts to form carbon deposits, while the comparison of surface properties of “fresh” and “used” samples evidenced a significant metal sintering occurring during reaction, proportional to the Si/Al ratio. The loss of metallic surface area was mainly connected to water formation, as proved in the measurements at high contact time in which a larger net drop between initial and final DME yield, resulting from a higher partial pressure of water, was recorded.