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2. Near ambient pressure photoelectron spectro-microscopy: from gas-solid interface to operando devices

Author

Amati, Matteo, Gregoratti, Luca, Zeller, Patrick, Greiner, Mark, Scardamaglia, Mattia, Junker, Benjamin, Ruß, Tamara, Weimar, Udo, Barsan, Nicolae, Favaro, Marco, Alharbi, Abdulaziz, Jensen, Ingvild J. T., Ali, Ayaz, and Belle, Branson D.

Subjects
Physics - Applied Physics, Condensed Matter - Materials Science
Abstract

Near Ambient Pressure Scanning Photoelectron Microscopy adds to the widely used photoemission spectroscopy and its chemically selective capability two key features: (i) the possibility to chemically analyse samples in a more realistic environmental, gas pressure condition, and (ii) the capability to investigate a system at the relevant spatial scale. To achieve these goals the approach developed at the ESCA Microscopy beamline at the Elettra Synchrotron facility combines the submicron lateral resolution of a Scanning Photoelectron Microscope with a custom designed Near Ambient Pressure Cell where a gas pressure up to 0.1 mbar is confined inside it around the sample. In this manuscript a review of experiments performed with this unique setup will be presented to illustrate its potentiality in both fundamental and applicative research such as the oxidation reactivity and gas sensitivity of metal oxides and semiconductors. In particular the capability to do operando experiment with this setup opens the possibility to perform investigations with active devices to properly address the real nature of the studied systems, because it can yield to more conclusive results when microscopy and spectroscopy are simultaneously combined in a single technique.

Published
2021
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3. Conductance Model for Single-Crystalline/Compact Metal Oxide Gas Sensing Layers in the Non-Degenerate Limit: Example of Epitaxial SnO$_2$(101)

Author

Simion, Cristian, Schipani, Federico, Papadogianni, Alexandra, Stanoiu, Adelina, Budde, Melanie, Oprea, Alexandru, Weimar, Udo, Bierwagen, Oliver, and Barsan, Nicolae

Subjects
Condensed Matter - Materials Science
Abstract

Semiconducting metal oxide (SMOX)-based gas sensors are indispensable for safety and health applications, e.g. explosive, toxic gas alarms, controls for intake into car cabins and monitor for industrial processes. In the past, the sensor community has been studying polycrystalline materials as sensors where the porous and random microstructure of the SMOX does not allow a separation of the phenomena involved in the sensing process. This lead to conduction models that can model and predict the behavior of the overall response, but they were not capable of giving fundamental information regarding the basic mechanisms taking place. The study of epitaxial layers is the definite prove to clarify the different aspects and contributions of the sensing mechanisms that are not possible to do by studying a polycrystalline sample. A detailed analytical model for n and p-type single-crystalline/compact metal oxide gas sensors was developed that directly relates the conductance of the sample with changes in the surface electrostatic potential. Combined DC resistance and work function measurements were used in a compact SnO2 (101) layer in operando conditions that allowed us to check the validity of our model in the region where Boltzmann approximation holds to determine surface and bulk properties of the material.

Published
2020
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6. List of contributors

Author

Badgoti, Ranveer Singh, primary, Barsan, Nicolae, additional, Bouhjar, Feriel, additional, Chauhan, Nar Singh, additional, Chinnamuthu, P., additional, Damasceno, Barbara Souza, additional, da Silva Sobrinho, Argemiro Soares, additional, Derbali, Lotfi, additional, Dutta, Somrita, additional, Gangwar, Jitendra, additional, Godoy, Armstrong, additional, Guaita, Julia Marí, additional, Gulati, Kapil, additional, Hlekelele, Lerato, additional, Horta, Isabela Machado, additional, Kumar, Naveen, additional, Kumar, Suresh, additional, Kumar, Gourav, additional, Kumar, Rajesh, additional, Kumari, Vijaya, additional, Kumari, Kavitha, additional, Leite, Douglas Marcel Gonçalves, additional, Lin, Shawn D., additional, Lu, Chung-Hsin, additional, Makgwane, Peter R., additional, Mavuso, Mlungisi A., additional, Meena, Mohan Lal, additional, Mhlongo, M.R., additional, Mittal, Anuj, additional, Mofokeng, S.J., additional, Mofokeng, Sefako, additional, Mokoena, Teboho P., additional, Motaung, David E., additional, Mphahlele-Makgwane, Mabel M., additional, Oosthuizen, Dina N., additional, Pereira, André Luis de Jesus, additional, Pooja, Pheiroijam, additional, Rana, Ravi, additional, Russ, Tamara, additional, Saroha, Bhavna, additional, Sharma, Yashpal, additional, Sharma, Ashok K., additional, Sharma, Pinki, additional, Sharma, Anuradha, additional, Singh, Rajan Kumar, additional, Siroha, Piyush, additional, Som, Sudipta, additional, Swart, Hendrik C., additional, Weimar, Udo, additional, Yadav, Monika, additional, Zhang, Ming, additional, Zhang, Tong, additional, and Zhou, Tingting, additional

Published
2023
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23. Contributors

Author

Abe, Hideki, primary, Aguir, Khalifa, additional, Aldao, Celso M., additional, Aleixandre, Manuel, additional, Barnett, Alejandro Oyarce, additional, Barsan, Nicolae, additional, Bernardini, Sandrine, additional, Boldrini, Leonardo C., additional, Bueno, Paulo Roberto, additional, Cao, Hongtao, additional, Chen, Hsin, additional, Cicoira, Fabio, additional, Colmenares, Luis C., additional, Cruz, Rebecca, additional, Dahl, Paul Inge, additional, Fiorido, Tomas, additional, Gaskov, Alexander, additional, Gavin, Ailbhe L., additional, Gemini-Piperni, Sara, additional, Granjeiro, Jose M., additional, Gu, Ding, additional, Hontañón, Esther, additional, Kong, Ling Bing, additional, Lawson, Bruno, additional, Leite, Paulo E., additional, Li, Ruidi, additional, Li, Xiaogan, additional, Li, Xiuying, additional, Liang, Lingyan, additional, Lucid, Aoife K., additional, Lyau, Jia-Bo, additional, Manjunathan, Pandian, additional, Marikutsa, Artem, additional, Masteghin, Mateus Gallucci, additional, Mei, Fangsheng, additional, Meng, Xiang, additional, Monterrubio, Francisco Alcaide, additional, Moriguchi, Isamu, additional, Notohara, Hiroo, additional, Orlandi, Marcelo Ornaghi, additional, Ribeiro, Ana R., additional, Ruan, Shuangchen, additional, Rumyantseva, Marina, additional, Santato, Clara, additional, Savioli, Julia, additional, Sayago, Isabel, additional, Shanbhag, Ganapati V., additional, Sharma, Vinita, additional, Staerz, Anna, additional, Su, Haibin, additional, Suman, Pedro H., additional, Suzuki, Takuya, additional, Tanabe, Toyokazu, additional, Umezawa, Naoto, additional, Urita, Koki, additional, Valitova, Irina, additional, Wang, Chuanhu, additional, Wang, Junjie, additional, Watson, Graeme W., additional, Weimar, Udo, additional, Wu, Hsiang-Chiu, additional, Xiao, Zhuohao, additional, Yuan, Tiechui, additional, Zhang, Tianshu, additional, Zhou, Kun, additional, and Zhou, Wei, additional

Published
2020
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26. List of contributors

Author

Barsan, Nicolae, primary, Degler, David, additional, Guth, Ulrich, additional, Hemeryck, Anne, additional, Izawa, Kuniyuki, additional, Lee, Jong-Heun, additional, Oprea, Alexandru, additional, Rebholz, Julia, additional, Schierbaum, Klaus, additional, Staerz, Anna, additional, Ulmer, Heiko, additional, Weimar, Udo, additional, and Wiemhöfer, Hans-Dieter, additional

Published
2019
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33. Noble Metal-Loaded WO 3 -Based Gases—The Gold Anomaly †.

Author

Staerz, Anna, Weimar, Udo, and Barsan, Nicolae

Subjects
*METAL clusters, *PRECIOUS metals, *GAS detectors, *TUNGSTEN oxides, *DETECTORS
Abstract

Tungsten oxide is one of the most commonly used materials for metal oxide-based gas sensors. In order to tune the sensing behavior, small clusters of noble metals are often added to the surface of WO3. Previously, it has been found that in the case of oxidized metal clusters, e.g., Rh and Pt additives, the Fermi-level pinning mechanism dominates. Unlike other noble metal surface clusters, gold seems to remain metallic under sensor operation. As a result, the behavior of WO3-based sensors was found to be significantly enhanced for all reducing gases and decreased for NO2. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Rapid Determination of Hexane Residues in Refined Vegetable Oils Using Semiconducting Metal Oxide-Based Sensors †.

Author

Kalinichenko, Asia, Junker, Benjamin, Weimar, Udo, and Bârsan, Nicolae

Subjects
VEGETABLE oils, SUNFLOWER seed oil, HEXANE, METALLIC oxides, PETROLEUM refining
Abstract

A simple, direct method for the determination residual hexane content in refined oils was developed, which makes use of commercial Semiconducting Metal Oxides (SMOX) sensors and is proposed as an alternative to the currently used standards (ISO 9832:2002, ISO 2719:2016). The main advantages are related to the direct measurement of the headspace of oil samples. The measurements are performed at an oil sample temperature of 30 °C and by spiking the samples with hexane in the 8–132 mg·kg−1 range, which is in line with the requirements of current standard for the maximum residue limit set by European Union regulation. Using separate measurements performed with the help of a computer-controlled gas mixing system it is possible to determine the relationship between the concentration of hexane in oil and in the headspace. [ABSTRACT FROM AUTHOR]

Published
2024
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