3D-printed ceramic membranes: Fabrication and hydrogen permeation performance

In this work, the possibility of using 3D printing technology as a tool to boost the widespread use of all-ceramic membranes operating at high temperatures for hydrogen separation and membrane reactors is proposed for the first time. Dense ceramic-ceramic composite membranes based on BaCe 0.65 Zr 0.20 Y 0.15 O 3-δ -Gd 0.2 Ce 0.8 O 2-δ were produced by 3D microextrusion. A suitable water-based ink was formulated and thermally/rheologically characterized. Both printing parameters and post-printing operations were carefully adjusted to obtain crack-free and planar membranes. In particular, the use of polyethylene glycol with the lowest molecular weight as desiccant liquid combined with a warm ethanol washing bath is crucial for the production of defect-free microextruded ceramics. The optimization of the whole ceramic process allows the fabrication of ceramic membranes with a relative density of 98.7 ± 1.1 % and a flexural strength of 98.4 ± 18.9 MPa. After activation with Pt nanoparticles, the 3D microextruded membranes show H 2 permeabilities of 0.21 and 0.32 mL min -1 cm -2 at 750 °C using a feed stream with respectively 50 % and 80 % of H 2 in He. These hydrogen fluxes are among the highest reported so far for symmetric all-ceramic membranes. • Dense composite ceramic membranes were produced by Direct Ink Writing • A suitable water-based ink was obtained and characterized • The use of a liquid desiccant drying method leads to crack-free membranes • Flexural strength values comparable to the conventional shaping method were achieved • H 2 flux of 0.32 mL min -1 cm -2 was registered at 750 °C feeding 80% of H 2 in He.