1 On the Effectiveness of Zeolite - Based Catalysts in 2 the CO 2 Recycling to DME : State of the Art and 3 Perspectives 4 5

Starting from the environmental issues related to global warming, climate change and 15 reduction of greenhouse gas emissions, this review paper describes how CO2 recycling can represent 16 a challenging strategy suitable to explore new concepts and opportunities for catalytic and 17 industrial development. In this view, the production of dimethyl ether (DME) from catalytic 18 hydrogenation of CO2 appears as a viable technology, able to meet also the ever-increasing need for 19 alternative environmentally-friendly fuels and energy carriers. Basic considerations on 20 thermodynamic aspects controlling DME production from CO2 are presented, then summarizing 21 the main catalytic systems developed in such field. Special attention is paid on the role assumed 22 during last years by zeolite-based systems, either in the methanol-to-DME dehydration step or in 23 the one-pot CO2-to-DME hydrogenation. On the whole, the productivity of DME results 24 significantly to be dependent on several catalyst features, linked not only to the metal-oxide phase 25 responsible for CO2 activation/hydrogenation, but also to specific properties of the zeolites (i.e., 26 topology, porosity, specific surface area, acidity, interaction with active metals, distributions of 27 metal particles, ...) influencing activity and stability of hybridized bifunctional heterogeneous 28 catalysts. 29 30