Direct recycling of 3D-printed Co-YDZ catalysts for ethanol steam reforming

Additive manufacturing enhances the catalyst performance via hierarchical design. To address environmental and resource concerns, this work aims to fabricate directly recycled 3D-printed monoliths using Direct-Ink Writing (DIW) from 100% recovered cobalt-zirconia powders. Virgin cobalt-zirconia monoliths were firstly fabricated by DIW of 3.0 to 7.0 wt% Co-enriched hydrogel-based ceramic inks, followed by calcination at 600°C in a single thermal treatment. After testing the catalytic performance of monoliths in ethanol steam reforming, 3D-printed cobalt-zirconia monoliths were fragmented and subjected to subsequent milling and sieving steps to recover composite cobalt-zirconia powders with the appropriate properties for reuse in DIW. The recovered powders, inks and monoliths were microstructurally, rheologically and catalytically characterized, and then compared to catalysts constituted by virgin materials. The rheology properties of inks for the recycled and virgin monoliths presented an appropriate printability. Furthermore, the catalytic performance of recycled monoliths was close to that exhibited by virgin catalysts. This study demonstrates the feasibility of directly recycling fully 3D-printed catalysts, potentially reducing the environmental impact with a circular production model to enhance sustainability in the catalyst industry. • A new approach to fabricate and recycle catalysts via 3D printing. • 3D-printed Co-YDZ catalysts are successfully recycled using 100% recovered powder. • All recovered-powder inks exhibit rheological properties suitable for Direct-Ink Writing. • H 2 production of recycled catalysts is close to that of the virgin ones. • Recycled 3 wt% Co catalysts yielded 67% H 2 , similar to virgin ones in reference studies.