Digital Light Processing 3D Printing of Structured γ-Al ₂ O ₃ Catalysts: Manufacturing Challenges and Mechanical Performance

3D printing, or additive manufacturing, is transforming the whole concept of manufacturing. When applied to catalyst shaping, 3D printing enables the creation of new architectures with the potential to significantly improve the mass and heat transfer rates in continuous reactors. This work analyzed the manufacturing process of structured γ-Al2O3 catalyst elements with the digital light processing (DLP) 3D printing technology. The influence of printing parameters and resin composition on the printability of ceramic resins was rationalized by developing a qualitative force balance for DLP printing, providing a framework to guide the formulation of ceramic resins for the production of heterogeneous catalysts. Dimensional accuracy studies were carried out to reveal the effect of light scattering on the resolution of the printed bodies along different directions. The strength of the structured bodies after polymer thermolysis was enhanced through repeated infiltration with colloidal boehmite nanoparticles with intermediate thermal treatments. The surface area was kept in a catalytically relevant range by using this approach. The effect of the printed lattice and wall thickness on the final mechanical performance was investigated, revealing the main parameters influencing the strength of the printed bodies. Drop tests demonstrated the robustness of the printed catalysts under impact. Overall, this study provides new insights into the design, fabrication, and strength of DLP 3D-printed structured catalysts, establishing a foundation for their future implementation in intensified catalytic reactors.