This work aims to prepare low-cost ceramic membranes to be used in a filtration process. The manufacturing of ceramic membranes uses the uniaxial dry pressing method. The raw materials from Tunisia, specifically clay, dolomite, and calcite, use organic waste as pore-forming agents. This study began with the characterization of the raw material to choose the best condition for membrane preparation. After the characterization, the ceramic supports were sintered at 950°C, 1000°C, and 1050°C for 2 h to obtain flat ceramic membranes of 25 mm in diameter. Critical parameters for the membrane performance such as porosity, density, mechanical strength, gas permeability, and water flux were determined. The best results were for the support made of 50% clay, 10% dolomite, 10% calcite, and 30% organic waste sintered at 1000°C with a porosity of 37% and a diametrical compression strength of 3.1 MPa. It showed a gas permeability of about 2624 L/h/m²/bar at 1.4 bar and a water flux of 1010 L/h/m² at a pressure of 0.9 bar. Three membranes were effectively tested to remove the fat in a solution containing 10% milk., This work was partially supported by the grant PID2021-125427OB-I00 funded by MCIN(ES)/AEI (10.13039/501100011033)., Peer reviewed

This work deals with the development of thermal energy storage (TES) materials with improved performance by direct ink writing (DIW) of highly porous (85 % total porosity) 3D coaxial ceramic supports for the encapsulation of phase change materials. These supports consist of rods with a boron nitride/vermiculite (77/23 by volume) composite core and a vermiculite shell. The approach is based on introducing a highly thermally conductive core into the filaments to improve the efficiency of the 3DTES structures, while maintaining a highly porous clay shell with a reported ability to be infiltrated by sodium nitrate and solar salt. A comparative study of the TES performance is conducted evaluating the thermal energy storage efficiency, thermal stability, energy storage density, and thermal conductivity. As demonstrated by finite element simulations, the enhanced thermal response of the coaxial 3DTES can be attributed to a multi-layered configuration of the filaments, also responsible for the increased anisotropy., This work was supported by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe” through Grant PID2021- 125427OB-I00; L. M.-S. acknowledges the financial support from MICINN/AEI/FEDER through the FPI contract Ref. PRE2019-091429 (2019 call)., Peer reviewed

Thick ceramic LiFePO₄ electrodes (800 µm thickness, ∼104 mg/cm² mass loading) are fabricated by direct ink writing using a sustainable aqueous-based suspension. This approach enables the formation of three-dimensional electrodes with a controlled porous architecture that enhances electrode/electrolyte wettability and mitigates ion and charge transport limitations typically associated with thick electrodes. The effects of debinding and sintering conditions on the microstructure and electrochemical performance are systematically investigated. In addition, the role of a super conductive carbon black (C65) additive is evaluated as a strategy to enhance electronic conductivity while preserving the ceramic nature of the electrodes. After optimization, fully ceramic binder-free electrodes are obtained. When assembled in full cells with Li₄Ti₅O₁₂ as the negative electrode and LP30 electrolyte, the optimized electrodes deliver areal capacities from 8.1 mAh/cm² at C/4 up to 14.4 mAh/cm² at C/25, retaining 5.9 mAh/cm² at 1 C., This work has been supported by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” through grant projects PID2020–12056RJ-I00, PID2021–125427OB-I00, PID2022–140373OB-I00 and PID2024–158338OB-I00; and through grant RYC2022–037989-I. APC Funding: Universidad Carlos III de Madrid (CRUE-Madroño 2025 Agreement). A. del Campo for advising on Raman measurements and spectra separation., Appendix A. Supplementary material, Peer reviewed

Formic acid (FA) is a promising liquid organic hydrogen carrier for safe and efficient hydrogen handling. FA dehydrogenation occurs under near-ambient conditions using palladium/activated carbon (Pd/AC) catalysts, but aspects like high Pd loading and gradual catalyst deactivation remain key challenges. This study investigates how the physicochemical properties of Pd nanoparticles and support characteristics influence the continuous process performance including FA conversion, evolved gas flow rate, total hydrogen production, and catalyst durability. Pd catalysts were prepared via wet impregnation using various precursors, powdered supports, and Pd loadings and evaluated in a fixed-bed reactor. The findings reveal that Pd/AC catalysts prepared with PdCl₂ precursor and nanopowdered AC are the most efficient. Strong electrostatic interactions between negatively charged PdCl₄²⁻ species and the positively charged AC surface during impregnation enhance nanoparticle support interactions, resulting in small (∼2 nm), highly dispersed Pd nanoparticles with a high Pd²⁺/Pd⁰ atomic surface ratio. Metal dispersion is the dominant factor influencing hydrogen production, surpassing the effects of both particle size and electronic state. Higher Pd loadings also increased catalyst durability, reducing regeneration frequency. This study provides valuable insights into the rational design of Pd/AC catalysts, paving the way for efficient FA utilization as a hydrogen carrier., The authors thank the financial support by the Government of Spain through the projects PID2021-125427OB-I00 and TED2021-130312B-I00 (MCIU/AEI/FEDER, UE). The authors thank the \u201CServicio Interdepartamental de Investigaci\u00F3n\u201D (Sidi) of the Universidad Autonoma de Madrid (UAM), and in particular Luis Larumbe from FTIR lab and Josu\u00E9 Friedrich from TXRF lab, the \u201CCentro Nacional de Microscop\u00EDa Electr\u00F3nica\u201D (ICTS-CNME) of the Universidad Complutense de Madrid (UCM), especially to Esteban Urones and the \u201CServicios Centrales de Apoyo a la Investigaci\u00F3n\u201D (SCAI), in particular Mar\u00EDa Dolores Marqu\u00E9s from Solidos Porosos Lab., Supporting information for this article is available on the WWW under https://doi.org/10.1002/cctc.202500411, Peer reviewed

Formic acid is a liquid organic hydrogen carrier for the safe hydrogen storage and transport. This study presents the fabrication of 3D-printed activated carbon (AC) monoliths by robocasting and their use as supports for Pd-based catalysts in the continuous hydrogen production (25–55 °C, 0.5–1 M FA, τ = 20–540 gCAT h L−1). The aim is to identify the optimal internal architecture for process scale-up.
While monolith geometry does not alter Pd nanoparticle properties (size ∼ 2.2 nm, dispersion 20–28%, Pd2+/Pd0 = 1), it significantly affects flow behaviour and structural robustness. The optimal design, incorporating a central axial channel, achieves initial TOFs up to 5087 h−1 at 55 °C. After over 100 h of operation, only a 23% activity loss is observed. Kinetic analysis reveals a second-order rate law in FA and 36 kJ mol−1 activation energy. These results demonstrate the potential of engineered 3D Pd/AC monoliths for efficient and scalable hydrogen production., The authors acknowledge financial support from the Government of Spain through the projects PID2021-125427OB-I00, TED2021-130312B–I00 and PID2024-157825OB-I00 (MCIU/AEI/FEDER, EU). The authors also thank the “Servicio Interdepartamental de Investigación" (SIdI) of the Universidad Autónoma de Madrid (UAM), with special appreciation to Luis Larumbe (FTIR lab) and María Jesús Redrejo (TXRF lab); the “Centro Nacional de Microscopía Electrónica” (ICTS-CNME) at Universidad Complutense de Madrid (UCM), particularly Esteban Urones; and the “Servicios Centrales de Apoyo a la Investigación” (SCAI), especially María del Valle Martínez de Yuso and María Dolores Marqués from the Porous Solids Lab., The following is the Supplementary data to this article., Peer reviewed

The solar salt, based on a mixture of 60 wt% of sodium nitrate and 40 wt% of potassium nitrate, is widely employed as thermal energy storage (TES) material in different technological applications. The encapsulation of this salt through the development of form-stable composites, core-shell materials or infiltrated 3D supports is increasingly being investigated to mitigate issues linked to the corrosive salt and the liquid leakage in its molten state that would decrease the energy storage performance. In the present work, 3D cellular vermiculite supports with different pattern designs have been additively manufactured (AM) by direct ink writing pseudoplastic aqueous clay-based inks. The heat-treated supports have been infiltrated with the solar salt, resulting in 3DTES with a high encapsulation capacity (86 %), and avoiding the corrosion of the skeleton and the leakage of the molten salt infiltrated into the support. These 3DTES are mechanically resistant (∼66 MPa), present a remarkable energy storage efficiency (85 %) and density (∼450 J g⁻¹), and exhibit a good thermal conductivity at 180 °C (∼1.0 W m⁻¹ K⁻¹). This study highlights the benefits of the AM approach for developing solar salt-based TES with improved energy storage performance., This work was supported by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” through Grant PID2021–125427OB-I00, Appendix A. Supplementary data, Peer reviewed

To address the growing demands for energy density, power, lifetime, and safety in Li-ion batteries, innovative processing techniques for high-capacity electrodes are essential. This study explores the additive manufacturing of ultra-thick LiFePO4 (LFP) electrodes (∼800 μm) using robocasting, as an alternative to traditional methods like screen printing or pressing. 3D LFP-based electrodes with cellular architectures and high mass loading (∼20 mg) are designed to enhance ion transport and energy density by increasing the surface area. Eco-friendly, aqueous-based printable inks are optimized for suitable rheological properties (viscosity, modulus, yield strength), in agreement with scalable and sustainable production. To improve mechanical strength and conductivity, 3 wt% of graphene oxide (GO) or graphene nanoplatelets (GNP) are incorporated to the ink formulation. After printing, 3D structures undergo thermal debinding and sintering to remove inactive components, yielding additive-free electrodes. Microstructural, mechanical, and electrical characterizations reveal that GO incorporation increases Vickers hardness by 50 % without compromising compressive strength. Electrochemical testing with Li4Ti5O12 (LTO) as the anode demonstrates promising performance, with LFP-GO electrodes achieving areal capacities up to 11 mA h cm−2 (21 mW h cm−2) at C/25. These results highlight the potential of robocasting to produce robust, high-performance thick electrodes for next-generation Li-ion batteries., This work has been supported by MCIN/AEI/10.13039/ 501100011033 and by “ERDF A way of making Europe” through Grant (projects PID2019-106662RBC43, PID2020-12056RJ-I00, PID2021–125427OB-I00 and PID2022-140373OB-I00) and the Madrid Government (Comunidad de Madrid-Spain) through the DROMADER- CM project (Y2020/NMT6584). APC Funding: Universidad Carlos III de Madrid (CRUE-Madro˜no 2025 Agreement., Data will be made available on request., Peer reviewed

Proyectos RTI2018-095052-B-I00, PID2019-105079RB-I00, PID2021-125427OB-I00 EIN2020-112153, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021–125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021–125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021–125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021–125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021–125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Founded by MCIN/AEI/10.13039/501100011033, Project Reference PID2021-125427OB-I00, Acronym “3DCERENE”, Peer reviewed

Graphene and its derivatives have been widely used to develop novel materials with applications in energy storage. Among them, reduced graphene oxide has shown great potential for more efficient storage of Na ions and is a current target in the design of electrodes for environmentally friendly Na ion batteries. The search for more sustainable and versatile manufacturing processes also motivates research into additive manufacturing electrodes. Here, the electrochemical responses of porous 3D-printed free-standing log-type structures fabricated using direct ink writing (DIW) with a graphene oxide (GO) gel ink are investigated after thermal reduction in a three-electrode cell configuration. The structures delivered capacities in the range of 50–80 mAh g−1 and showed high stability for more than 100 cycles. The reaction with the electrolyte/solvent system, which caused an initial capacity drop, was evidenced by the nucleation of various Na carbonates and Na2O. The incorporation of Na into the filaments of the structure was verified with transmission electron microscopy and Raman spectroscopy. This work is a proof of concept that structured reduced GO electrodes for Na ion batteries can be achieved from a simple, aqueous GO ink through DIW and that there is scope for improving their performance and capacity., This research was funded by MICINN (Spain) through projects PID2020-120562RJ-I00 and PID2021-125427OB-I00., Peer reviewed

The demand for hydrogen has extraordinarily grown during the last years, being one of the most attractive forms
of fuels to produce green energy. Cubic zirconia ceramics are considered promising catalytic supports, and the
additive manufacturing of porous 3D structures based on these ceramics could enhance their catalytic performance.
Herein, lightweight highly porous (up to 88%) 3D patterned 8 mol% yttria-stabilized cubic zirconia
(8YSZ) scaffolds are manufactured by robocasting from pseudoplastic aqueous-based inks to produce catalytic
supports for the hydrogen (H2) production. These scaffolds are thermally treated at temperatures ranging between
1000 and 1400 ◦C and, hence, mechanically and electrically characterized. 3D 8YSZ structures sintered at
1200 ◦C, with an appropriate balance between high porosity (86%) and compressive strength (3.7 MPa), are
impregnated with palladium (Pd) catalytic nanoparticles and employed in the catalytic dehydrogenation of
renewable formic acid (FA) using a fixed-bed reactor. 3D Pd/8YSZ catalyst leads to the continuous production of
CO-free H2 with a FA conversion of 32% at T = 55 ◦C., Proyectos RTI2018-095052-B-I00, PID2019-105079RB-I00, PID2021-125427OB-I00 EIN2020-112153, Peer reviewed

[EN] Assessing and predicting the thermal conductivity (κ) of macroporous materials is particularly important for
additive manufactured 3D structures, as they offer considerable potential for tuning architectures and properties.
In this work, finite element methods (FEM) are used to simulate the transient plane source test in 3D logpile
lattices, approaching the effect of interfacial thermal contact resistances on κ measurement. Besides, the influence
of different geometrical parameters (rod diameter, macropore size and overlapping between rods in
consecutive layers) and the κ of the strut material on the anisotropic thermal conductivity of 3D lattices are
investigated. The models are validated using experimental data for 3D composite structures of γ-Al2O3 with
graphene nanoplatelet contents up to 18 vol%, as well as with reported data for alike scaffolds, all printed by
robocasting. Results have strong impact for the application of novel 3D structures in energy production and
storage, catalysis and heat transfer-related fields., This work was supported by the Spanish Ministry of Science and Innovation through RTI2018-095052-B-I00 and PID2021-125427OB-I00 (MICINN/AEI/FEDER, UE) and EIN2020-112153 (MICINN/AEI/10.13039/501100011033) projects, the latter also supported by the European Union through “NextGenerationEU/PRTR”. L. M.-S. acknowledges the financial support from MICINN/AEI/FEDER through the FPI contract Ref. PRE2019-091429 (2019 call)., Peer reviewed

[EN] The development of structured catalyst supports to promote the chemical process intensification is of great interest, and porous activated carbon (AC) is an excellent material to tackle this challenge. In addition, the current increasing hydrogen demand and its limitations in transportation and storage require of novel approaches. Here, highly porous and robust 3D printed patterned AC-based architectures have been additive manufactured by using a direct ink writing technology. Different AC inks containing a boehmite gel with no organic additions have been rheologically characterized to select the most suitable ink for building AC supports, which have been thermally treated to promote solid-solid contacts and increase the robustness (strength of ~0.5 MPa) while keeping high porosity (86%). The AC supports have been then impregnated with a 5 wt.% of palladium (Pd) precursor to develop a 3D Pd/AC catalyst able to generate hydrogen from the dehydrogenation of formic acid (FA), a very promising liquid organic hydrogen carrier, in a fixed-bed reactor. These 3D catalysts have produced CO-free hydrogen from FA under ambient conditions with a FA conversion of 81% and a hydrogen flow rate of 6 mL·min-1. Long-term experiments in continuous mode operation have evidenced a good catalytic stability and recyclability. These results demonstrate that 3D Pd/AC catalysts exhibit a great potential to develop a new technology for using FA as hydrogen carrier., This work was supported by the Grants PID2021-125427OB-I00 and TED2021-130312B-I00 funded by MICIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, and by the Grant EIN2020-112153 funded by MCIN/AEI/10.13039/501100011033 and by “European Union NextGenerationEU/PRTR”. G. Vega acknowledges the Universidad Autónoma de Madrid for the Predoctoral contract. M. Navarro acknowledges the Community of Madrid for her contract under the “Programa Investigo”., Peer reviewed

Molten salts, phase change materials commonly employed in thermal energy storage (TES) systems, are widely known to enhance the efficient use and storage of solar energy in concentrated solar power (CSP) plants. Here, three-dimensional TES (3DTES) have been manufactured from highly porous (up to ∼90 %) 3D printed patterned vermiculite (V) and alumina (Al2O3) supports, which have been infiltrated with molten sodium nitrate salt (nn) and solar salt (ss). These 3DTES have been validated under real concentrated solar radiation in a parabolic solar furnace. Among the different 3DTES, those based on V-nn exhibits the best efficiency for the conversion of the incident solar radiation into heat; whereas Al2O3-nn transfers the heat more efficiently and allows a faster charging-discharging cyclability due to its higher thermal conductivity. This study confirms the benefits of additive manufacturing to develop a new class of innovative TES for CSP applications. © 2024 The Authors, This work was supported by MCIN/AEI/ 10.13039/501100011033
and by “ERDF A way of making Europe” through Grant
PID2021–125427OB-I00; and by the French “Investments for the future”
program managed by the National Agency for Research under contract
ANR-10-EQPX-49-SOCRATE. I. D.-H. is grateful to the JECS Trust for
funding the visit to PROMES-CNRS laboratory (Contract No. 2023357)., Supplementary data associated with this article can be found in the online version at doi:10.1016/j.jeurceramsoc.2024.116975, Peer reviewed

Molten salts stand out as excellent thermal energy storage (TES) materials for medium-high temperature applications, including renewable energies like concentrated solar power systems. However, these salts commonly exhibit energy efficiencies below expectations, are highly corrosive to the containers, and can present liquid leakage in their molten state, compromising their storage capabilities. Here, highly macro-porous (~93 %) three-dimensional (3D) expanded vermiculite (EV) supports have been additive manufactured (AM) by robocasting using a strategy based on the combination of optimized patterned architectures with the addition of activated carbon, as pore former, to the printable EV inks. The resulting 3D EV supports have been infiltrated with molten sodium nitrate, leading to 3DTES with an outstanding thermal energy storage efficiency of ~90 %, maintained after thermal cycling, and an energy storage density of 613 J·g−1. These 3DTES present low supercooling degree (2.7 °C), good thermal conductivity (~1.0 W·m−1·K−1), and high corrosion and mechanical resistances (compressive strength of ~46 MPa) despite their lightness (~1.6 g·cm−3). The patterned EV support based on sinusoidal-shaped porous struts keeps the molten salt fully encapsulated into the 3D structure and avoids the liquid leakage. These findings encourage the use of AM to develop novel TES materials able to overcome the drawbacks of phase change materials for energy applications. © 2023, This work was supported by the Grant PID2021-125427OB-I00
funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of
making Europe”, and by the Grant EIN2020-112153 funded by MCIN/
AEI/10.13039/501100011033 and by “European Union NextGenerationEU/
PRTR”., Supplementary data to this article can be found online at https://doi. org/10.1016/j.est.2024.111108., Peer reviewed

Three-dimensional (3D) architected electrode materials are expected to exhibit advantageous properties such as enlarged surface area, increased mass transfer, enhanced adsorption and more active sites exposed. In this paper, boron-doped diamond (BDD) electrodes on 3D printed patterned silicon carbide (SiC) scaffolds have been fabricated using chemical vapor deposition (CVD). The stabilization of the plasma sphere by using clamshell type CVD reactor, introducing the outer protecting plate, the optimization of CVD parameters, and the design of 3D-SiC scaffolds improved the sp3/sp2 ratio, uniformity and growth rate of BDD. 3D-BDD electrodes exhibit enough electrical conductivity for electrochemical applications. The preliminary test for electrochemical carbon dioxide reduction (CO2R) has showed the potential advantages of this type of 3D structured BDD electrodes. © 2024 Elsevier B.V., This work was supported by the Grant PID2021-125427OB-I00
funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way
of making Europe”. M. B. acknowledges the financial support from JSPS
through FY2020 JSPS Invitational Fellowships for Research in Japan
(short-term, Fellowship ID S20030). Furthermore, this work was partly
supported by Grant-in-Aid for Scientific Research A 23H00288., Peer reviewed

The dynamic elastic response of 3D macroporous scaffolds is crucial to determine their performance under operating conditions. In this work, the elastic behaviour of 3D printed bar-shaped scaffolds of γ-Al2O3 and γ-Al2O3/graphene nanoplatelets (GNP) composites (18 vol%), fabricated by Direct Ink Writing (DIW), is investigated. Dynamic Young's modulus (E) is studied by the Impulse Excitation Technique (IET) and compared with theoretical results obtained by Finite Element Methods (FEM) and the multi-scale material simulator GeoDict®. In addition, Resonant Ultrasound Spectroscopy (RUS) is used to characterize E of single- and bi-material coaxial struts. While additions of GNP to γ-Al2O3 lead to an increase in E, it decreases in the coaxial struts due to the development of thermal residual stresses at the core/shell interface. The suitability of combining experimental and theoretical methods for the analysis of the elastic properties and the anisotropy associated with the lattice pattern is demonstrated. © 2024 The Authors, This work was supported by the Grant PID2021–125427OB-I00
funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way
of making Europe”. L. M.-S. acknowledges the financial support from
MICINN/AEI/FEDER through the FPI contract Ref. PRE2019–091429
(2019 call). M.K. acknowledges financial support from Czech Science
Foundation (project No. 24–11074 J)., Supplementary data associated with this article can be found in the online version at doi:10.1016/j.jeurceramsoc.2024.116771., Peer reviewed

The encapsulation of phase change materials (PCMs) into additive manufactured porous supports is attracting great interest for developing thermal energy storage (TES) materials with improved energy performance. Here, highly porous (86 %) self-supported 3D activated carbon/alumina supports are fabricated by direct ink writing (DIW) and, then, infiltrated with solar salt, a highly corrosive PCM with a melting temperature around 220 °C commonly employed in concentrated solar power plants. This novel, robust, chemically compatible, and lightweight infiltrated 3DTES exhibits good thermal energy storage efficiency (70 %) and thermal stability, high energy storage density (381 J g−1), and avoids the liquid leakage of the molten salt. Besides, the 3D activated carbon/alumina support promotes a better ability to absorb solar energy (79 %) and enhances the thermal conductivity of the solar salt (up to 64 %). These results validate the use of DIW for manufacturing innovative TES with an enhanced energy storage behaviour. © 2024 The Authors, This work was supported by the Grant PID2021-125427OB-I00
funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of
making Europe”. This work was supported by the French “Investments
for the future” program managed by the National Agency for Research
under contract ANR-10-EQPX-49-SOCRATE. I. D.-H. is grateful to the
JECS Trust for funding the visit to PROMES-CNRS laboratory (Contract
No. 2023357). Authors thank C. Escape (PROMES-CNRS, UPR 8521) for
his experimental assistance in the optical reflectance measurements., Supplementary data to this article can be found online at https://doi. org/10.1016/j.oceram.2024.100648, Peer reviewed

Coaxial 3D structures based on ceramic materials with distinct properties are of great interest in a wide range of fields due to their enhanced ability to modulate structural and functional properties. In this work, 3D patterned structures based on bi-component filaments with a core-shell arrangement have been additively manufactured in a single step by material extrusion. A system has been designed consisting of two concentric syringes for simultaneous printing of pseudoplastic core and shell ceramic inks with a single pressure device. Aqueous boehmite and boehmite/graphene nanoplatelets (GNP) composite inks have been formulated. The rheology of both inks has been matched to ensure the printability and integrity of the boehmite (core)-composite (shell) layout and its reverse. The as-printed coaxial scaffolds have been treated at 500 ºC for 2 h in nitrogen atmosphere to transform boehmite to γ-alumina while the GNP remain undamaged. The thermal properties and the heat transfer of these robust coaxial structures have been experimentally analysed using the transient pulse source method and a high-resolution infrared camera, respectively. Besides, they have been theoretically simulated by finite element methods. These coaxial architectures promote higher thermal anisotropy as compared to mono-material scaffolds, allowing better control of the heat fluxes. The mechanical behaviour of the different lattice materials has been assessed through compression tests to calculate the strength and the apparent elastic modulus; and the fracture surface of the lattice struts after failure has also been examined. © 2024 The Authors, This work was supported by the Grants PID2021–125427OB-I00 and PID2020–120562RJ-I00 funded by MICIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, and by the Grant EIN2020–112153 funded by MCIN/AEI/10.13039/501100011033 and by “European Union NextGenerationEU/PRTR”. L. M.-S. acknowledges the financial support from MICINN/AEI/FEDER through the FPI contract Ref. PRE2019–091429 (2019 call)., Supplementary data associated with this article can be found in the online version at doi:10.1016/j.addma.2024.104018., Peer reviewed