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