In Situ FT-IR Characterization of CuZnZr/Ferrierite Hybrid Catalysts for One-Pot CO₂-to-DME Conversion

Abstract

CO2 hydrogenation to dimethyl ether (DME) is a promising strategy to drive the current chemical industry towards a low-carbon scenario since DME can be used as an eco-friendly fuel as well as a platform molecule for chemical production. A Cu‒ZnO‒ZrO2/ferrierite (CZZ/FER) hybrid grain was recently proposed as a catalyst for CO2-to-DME one-pot conversion exhibiting high DME productivity thanks to the unique shape-selectivity offered by ferrierite zeolite. Nevertheless, such a catalyst deactivates but no direct evidence has been reported of activity loss over time. In this work, CZZ/FER catalysts with different acidity levels were characterized with the FTIR technique before and after reactions, aiming to give new insights about catalyst deactivation. Results show that activity loss can be related to both (i) copper particle sintering, which decreases CO2 activation towards methanol, and (ii) acidity loss due to H+/Cu2+ ion exchange.

Keywords

• CO₂ hydrogenation
• dimethyl ether
• Cu‒ZnO‒ZrO₂
• ferrierite zeolite
• catalyst deactivation
• zeolite Brønsted/Lewis acidity
• FTIR