Optimization of 3D printing conditions for BaCe0.6Zr0.3Y0.1O3-δ in the construction of amperometric high-temperature H2 sensors

• PVP- and PEG2000-based BCZY pastes did not allow for high-density elements. • PEG400-based BCZY pastes were enabled high-density elements. • Nozzle diameter was crucial to minimize element wall thickness. • Larger area enabled higher sensitivity and a wider range for amperometric sensors. • The tested sensors took fast response/recovery times, high precision and accuracy. Proton-conducting ceramics, particularly BaCe 0.6 Zr 0.3 Y 0.1 O 3-δ (BCZY), are promising materials for hydrogen energy applications. However, traditional fabrication methods are limited in their ability to produce complex geometries. Extrusion-based 3D printing presents a promising alternative, enabling the fabrication of customized designs with the advantage of fast prototyping. This study optimized the slurry composition and 3D printing parameters for BCZY ceramics to fabricate pellets and one-end closed tubes for amperometric hydrogen sensors. Results showed that a paste with 83 % BCZY, 8.5 % water, and 8.5 % PEG400 yielded a density of 96 % after sintering at 1700 °C for 1 h. The nozzle diameter during printing was the most influential parameter affecting wall thickness. Sensors constructed from one-end closed tubes exhibited higher sensitivity (20,571 μm·mbar -1 ) and a broader linear range (0.010 - 0.050 mbar) compared to pellet-based sensors. 3D printing proves to be an effective method for producing BCZY ceramic components with tailored geometries for hydrogen sensing.