Abstract
Rare-earth oxycarbonates Ln2O2CO3 (Ln = rare-earth element) have been identified as materials for chemoresistive CO2 gas sensors. Among them, previous studies identified monoclinic La2O2CO3 as the best performing one. However, not all rare-earth elements have been investigated and, moreover, La2O2CO3 monoclinic phase is metastable and this can influence the long term performance. In this work, we have synthesized rare-earth oxycarbonates Ln2O2CO3 (Ln = La, Nd, and Sm) including monoclinic and hexagonal La2O2CO3, rare-earth oxides Ln2O3 (Ln = Nd, Sm, Gd, Dy, Er, and Yb) and LnO2 (Ln = Ce) by calcination of oxalate hydrate or the acetate hydrate precursors in air. All the materials, except for CeO2 and Nd2O3, were sensitive to CO2. All CO2 sensitive materials, except for monoclinic La2O2CO3 and Nd2O2CO3, were stable and their performance is sufficient for practical use. Hexagonal La2O2CO3 shows the best overall performance. The results of operando investigations indicate that the origin of CO2 sensing is the competitive adsorption between carbonates and hydroxyl groups.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.