3D printed CuZnAl₂O₃-based catalysts for direct CO₂ hydrogenation to DME, optimization and scale up

This work reports the development, optimization and subsequent scale-up of 3D printed catalyst structures for direct CO₂ hydrogenation to DME. To ensure compatibility between the used Cu-ZnO-Al₂O₃ (CZA) catalyst and the acid form H-ZSM-5 co-catalyst, a new binary polymeric binder system, based on polyethyleneimine (PEI) and methylcellulose (MC), was selected. The 3D-printing paste composition was optimized through 2 successive Design of Experiments (DOE) to achieve (i) good textural properties that ensure catalytic activity and (ii) improved mechanical integrity and printability. The DOE unveiled the critical link between the pH of the printing paste and the preservation of textural properties and catalytical activity of the printed catalysts. Finally, the successful scale-up of the 3D-printed catalyst structures was demonstrated using the optimized printing paste, and the performance of the final catalysts was evaluated by catalytic testing and accompanied X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analyses.