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

Abstract

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 3.0–7.0¿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.

The research reported in this paper received support from the EU Regional Development Fund through the Operational FEDER of Catalonia 2014–2020 RIS3CAT-BASE3D, from projects PID2024–156765OB-C21, PID2021–125150OB-I00, PID2021–126614OB-I00, PID2022–137274NB-C32, and PID2022–137626OB-C31 funded by MCIN/AEI/10.13039/501100011033, EU and FEDER. This work was part of Maria de Maeztu Units of Excellence Programme CEX2023–001300-M funded by MCIN/AEI/10.13039/501100011033. This research was also supported by MCIN with funding from NextGenerationEU (PRTR-C17.I1) within the Planes Complementarios con CCAA (Area of Green Hydrogen and Energy) and it has been carried out in the CSIC Interdisciplinary Thematic Platform (PTI+) Transición Energética Sostenible+ (PTI-TRANSENER+). Additional funding was also received from AGAUR (Agency for Administration of University and Research) under grant numbers 2021 SGR 01053 and 01061, and 2017 SGR 1165, and from T02–20R (DGA). S.A.R. acknowledges the Ph.D. scholarship received from Universitat Politècnica de Catalunya and Banco Santander (Predoctoral grant 2020 FPU-UPC_068). T.V. acknowledges the Ph.D. scholarship received from the Barcelona Research Center in Multiscale Science and Engineering of the UPC. M.M. and J.Ll. are Serra Hunter Fellows and J.Ll. and M.P.G. are grateful to ICREA Academia Program (Generalitat de Catalunya). Furthermore, the use of Servicio General de Apoyo a la Investigación (SAI, University of Zaragoza) and the Advanced Microscopy Laboratory (LMA) are also acknowledged. The authors also thank Guillaume Kiefer, Oscar Escuer and Marc Torrente for their assistance during this research.

Postprint (published version)