Electrochemical sensors based on solid-state proton conductor ceramics can be used for that purpose. These materials have attracted significant interest because of their chemical and physical durability, especially at elevated temperatures. These electrolytes are perovskite-type materials with electrical carriers, positive holes, excess electrons and oxide ion vacancies. In previous work [1], amperometric hydrogen sensors based on BaCe0.6Zr0.3Y0.1O3-α (BCZY) electrolyte have been developed and tested in hydrogen atmospheres obtaining good results. These prototypes were constructed using 13 mm BCZY disks obtained by uniaxial pressure.
In the present work, hydrogen sensors based on BCZY were constructed and evaluated in amperometric mode. The BCZY powder was disk-shaped using uniaxial pressure and 3D printing. Sensors were constructed as follows: first, sintered disks were platinized using platinum ink. Then, disks were sealed with a glass binder to alumina tubes. This way, the external face of the disk acted as a working electrode (WE) and the inner part of the sensor as a counter electrode (CE). 3D printed disks were fabricated using a Delta WASP 2040 ceramic 3D printer. For that, the ceramic powder was mixed with PEG400 and water until a viscous paste was obtained. Once green bodies were dried, they were heated for debinding and sintering using an optimized thermal program to reduce porosity. XRD (for crystallographic phases) and SEM (for microstructural defects and sintering) were used for the 3D printed and uniaxial pressed sintered disks characterization. The amperometric response of sensors constructed with both electrolytes (the uniaxially pressed and the 3D printed disks) was compared.
[1] A. Hinojo, I. Soriano, J. Abellà, S. Colominas, Evaluation of High-Temperature Hydrogen Sensors Based on BaCe0.6Zr0.3Y0.1O3-α and Sr(Ce0.9Zr0.1)0.95Yb0.05O3-α Perovskites for Industrial Applications, Sensors. 20 (2020) 7258. https://doi.org/10.3390/s20247258.