Robocasting of controlled porous CaSiO3-SiO2 structures: Architecture - Strength relationship and material catalytic behavior

Wollastonite (CaSiO3) based porous structures are useful in a wide range of applications including catalysis. Furthermore, the use of additive manufacturing techniques for the production of on-demand structures with controlled porosity are widely used for numerous materials. In the present work, CaSiO3 was synthesized by co-precipitation method resulting in a fine CaSiO3-SiO2 powder, which was processed to fabricate regular porous structures using the robocasting technique. Cylindrical structures of 10 mm in diameter and 10 mm in height were robocast following two different arrangement patterns, i.e., orthogonal and honeycomb with two different pore sizes (350 and 500 mu m). In general, the orthogonal structures showed better geometrical and dimensional accuracy than honeycomb ones. The compression test showed that orthogonal structures were more reliable, while the honeycomb structures exhibited higher compressive strength. The reasons are on the differences in porosity and pore architecture between them. Additionally, the catalytic properties of the CaSiO3-SiO(2 )powder were studied by the decomposition of isopropyl alcohol. The CaSiO3-SiO2 showed strong selective basic catalytic properties, leading on the dehydrogenation of the alcohol producing acetone with a yield up to 92% at 350 degrees C. In summary, the CaSiO3-SiO2 robocast structures have a significant potential for self-supporting catalytic reactors.