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

• Design of experiment study of parameters aided desired improvement of 3D printing process. • Both acid and PEI binder affected the pH of the printing paste and the specific surface area. • Lower pH values, result in zeolite degradation (dealumination) and possible CZA-dissolution. • Catalytic testing of double monolith reactor shows increased conversion and yield. • Selectivity for DME decreases with temperature (60–30 % 240–290 °C). This work reports the development, optimization and subsequent scale-up of 3D printed catalyst structures for direct CO 2 hydrogenation to DME. To ensure compatibility between the used Cu-ZnO-Al 2 O 3 (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.