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ORIGINAL RESEARCH article

Front. Chem.
Sec. Electrochemistry
Volume 12 - 2024 | doi: 10.3389/fchem.2024.1480356

Emerging NO2 gas sensing on substitutionally doped Fe on NiWO4 SCES insulator

Provisionally accepted
Seung Yong Lee Seung Yong Lee *Gi H. Park Gi H. Park Min Y. Kim Min Y. Kim Sanghyun Ji Sanghyun Ji Ha E. Choa Ha E. Choa Gi H. Han Gi H. Han Jeong Y. Hwang Jeong Y. Hwang Kyu Hyoung Lee Kyu Hyoung Lee *
  • Yonsei University, Seoul, Republic of Korea

The final, formatted version of the article will be published soon.

    In this study, we demonstrate the emergence of NO2 gas sensing capabilities in the typically nonactive NiWO4, a strongly correlated electron system (SCES), by introducing substitutional Fe at the Ni site. NiWO4 typically exhibits strong Coulombic repulsion between Ni atoms, resulting in a large band gap of over 3.0 eV and insulating behavior. This correlated behavior is clearly reflected in the significant increase of band gap when considering the Hubbard U correction for the cations, bringing the theoretical value closer to the observed value. The single-phase Fe0.5Ni0.5WO4 displays a notable shift in the [NiO6] symmetric vibration mode and an increase in magnetization. Additionally, theoretical calculations confirm the preservation of the wide band gap, with the Fe and O levels generated within the band gap. These findings indicate that Fe located in Ni sites modulate the Coulombic repulsion in NiWO4 SCES insulators. Unlike the poor gas sensing performance of intrinsic NiWO4, Fe0.5Ni0.5WO4 exhibits a significant NO2 response (Rg/Ra) of 11 at 200°C than other gases and a limit of detection (LOD) of 46.4 ppb. This study provides one pathway into how gas sensing performance can be realized in strongly correlated electron insulators with large band gaps through the introduction of dopant levels at cation sites.

    Keywords: metal oxide, NiWO4, Gas sensor, NO2 gas, SCES

    Received: 13 Aug 2024; Accepted: 14 Oct 2024.

    Copyright: © 2024 Lee, Park, Kim, Ji, Choa, Han, Hwang and Lee. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Seung Yong Lee, Yonsei University, Seoul, Republic of Korea
    Kyu Hyoung Lee, Yonsei University, Seoul, Republic of Korea

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.