{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,14]],"date-time":"2026-02-14T04:37:10Z","timestamp":1771043830388,"version":"3.50.1"},"reference-count":49,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2019,11,20]],"date-time":"2019-11-20T00:00:00Z","timestamp":1574208000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001659","name":"Deutsche Forschungsgemeinschaft","doi-asserted-by":"publisher","award":["HE 4516\/6-1"],"award-info":[{"award-number":["HE 4516\/6-1"]}],"id":[{"id":"10.13039\/501100001659","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Understanding the mode of operation of gas sensors is of great scientific and economic interest. A knowledge-based approach requires the development and application of spectroscopic tools to monitor the relevant surface and bulk processes under working conditions (operando approach). In this review we trace the development of vibrational Raman spectroscopy applied to metal-oxide gas sensors, starting from initial applications to very recent operando spectroscopic approaches. We highlight the potential of Raman spectroscopy for molecular-level characterization of metal-oxide gas sensors to reveal important mechanistic information, as well as its versatility regarding the design of in situ\/operando cells and the combination with other techniques. We conclude with an outlook on potential future developments.<\/jats:p>","DOI":"10.3390\/s19235075","type":"journal-article","created":{"date-parts":[[2019,11,20]],"date-time":"2019-11-20T11:06:03Z","timestamp":1574247963000},"page":"5075","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["Application of Raman Spectroscopy to Working Gas Sensors: From in situ to operando Studies"],"prefix":"10.3390","volume":"19","author":[{"given":"Ann-Kathrin","family":"Elger","sequence":"first","affiliation":[{"name":"Eduard-Zintl-Institut f\u00fcr Anorganische und Physikalische Chemie, Technische Universit\u00e4t Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany"}]},{"given":"Christian","family":"Hess","sequence":"additional","affiliation":[{"name":"Eduard-Zintl-Institut f\u00fcr Anorganische und Physikalische Chemie, Technische Universit\u00e4t Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2019,11,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0925-4005(99)00133-1","article-title":"Semiconducting Oxides as Gas-Sensitive Resistors","volume":"57","author":"Williams","year":"1999","journal-title":"Sens. Actuators B Chem."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.mseb.2007.01.044","article-title":"Metal Oxides for Solid-State Gas Sensors: What Determines our Choice?","volume":"139","author":"Korotcenkov","year":"2007","journal-title":"Mater. Sci. Eng. B"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1016\/j.mseb.2017.12.036","article-title":"Semiconductor Metal Oxide Gas Sensors: A Review","volume":"229","author":"Dey","year":"2018","journal-title":"Mater. Sci. Eng. B"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"3826","DOI":"10.1002\/anie.200602597","article-title":"In Situ and Operando Spectroscopy for Assessing Mechanisms of Gas Sensing","volume":"46","author":"Gurlo","year":"2007","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3607","DOI":"10.1002\/anie.201207258","article-title":"Monitoring Gas Sensors at Work: Operando Raman-FTIR Study of Ethanol Detection by Indium Oxide","volume":"52","author":"Gurlo","year":"2013","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/anie.201908871","article-title":"Elucidating the Mechanism of Working SnO2 Gas Sensors Using Combined Operando UV\/Vis, Raman, and IR Spectroscopy","volume":"58","author":"Elger","year":"2019","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"11792","DOI":"10.1021\/acs.jpcc.5b04082","article-title":"Identifying the Active Oxygen Species in SnO2 Based Gas Sensing Materials: An Operando IR Spectroscopy Study","volume":"119","author":"Degler","year":"2015","journal-title":"J. Phys. Chem. C"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"8620","DOI":"10.1039\/b906829e","article-title":"Operando X-Ray Absorption Spectroscopy Studies on Pd-SnO2 Based Sensors","volume":"11","author":"Koziej","year":"2009","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/j.snb.2015.10.040","article-title":"Extending the Toolbox for Gas Sensor Research: Operando UV\/vis Diffuse Reflectance Spectroscopy on SnO2-based Gas Sensors","volume":"224","author":"Degler","year":"2016","journal-title":"Sens. Actuators B Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"2841","DOI":"10.1002\/anie.201004499","article-title":"The Structure and Behavior of Platinum in SnO2-Based Sensors under Working Conditions","volume":"50","author":"Koziej","year":"2011","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"25064","DOI":"10.1021\/acs.jpcc.7b06253","article-title":"Ambient Humidity Influence on CO Detection With SnO2 Gas Sensing Materials. A Combined DRIFTS\/DFT Investigation","volume":"121","author":"Wicker","year":"2017","journal-title":"J. Phys. Chem. C"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1002\/cphc.200900773","article-title":"Active Metal Electrode-Oxide Interface in Gas Sensor Operation Probed by In Situ and Time-Resolved X-Ray Spectroscopy","volume":"11","author":"Gurlo","year":"2010","journal-title":"ChemPhysChem"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"893","DOI":"10.1021\/cm0490470","article-title":"Raman Surface Vibration Modes in Nanocrystalline SnO2: Correlation With Gas Sensor Performances","volume":"17","author":"Rumyantseva","year":"2005","journal-title":"Chem. Mater."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1609","DOI":"10.1016\/j.proeng.2014.11.673","article-title":"Correlations Phonon Spectrum-Sensitivity in Metal-Oxide Gas Sensors","volume":"87","author":"Mihaila","year":"2014","journal-title":"Procedia Eng."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"9998","DOI":"10.1021\/jp811131t","article-title":"A Controlled Method to Synthesize Hydrid In2O3\/Ag Nanochains and Nanoparticles: Surface-Enhanced Raman Scattering","volume":"113","author":"Du","year":"2009","journal-title":"J. Phys. Chem. C"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1007\/s002160050844","article-title":"Correlation Between XPS, Raman and TEM Measurements and the Gas Sensitivity of Pt and Pd Doped SnO2 Based Gas Sensors","volume":"361","author":"Kappler","year":"1998","journal-title":"Fresenius J. Anal. Chem."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.snb.2009.02.051","article-title":"Raman and MASNMR Studies to Support the Mechanism of Low Temperature Hydrogen Sensing by Pd Doped Mesoporous SnO2","volume":"138","author":"Manjula","year":"2009","journal-title":"Sens. Actuators B Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"872","DOI":"10.1016\/j.snb.2013.07.016","article-title":"Enhanced Ethanol-Gas Sensing Performance of Ce-Doped SnO2 Hollow Nanofibers Prepared by Electrospinning","volume":"188","author":"Mohanapriya","year":"2013","journal-title":"Sens. Actuators B Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"491","DOI":"10.1016\/j.ssc.2008.10.007","article-title":"Optical Investigation of the Size Effects on NO2 Adsorption in SnO2 Nanoparticles","volume":"148","author":"Wie","year":"2008","journal-title":"Solid State Commun."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"7764","DOI":"10.1166\/jnn.2019.16736","article-title":"The Role of In-Plane Oxygen Vacancy Defects in SnO2 Nanoparticles for CH4 Sensing","volume":"19","author":"Sahu","year":"2019","journal-title":"J. Nanosci. Nanotechnol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"756","DOI":"10.1002\/jrs.1687","article-title":"Nanopowders and Nanostructured Oxides: Phase Transitions and Surface Reactivity","volume":"38","author":"Pagnier","year":"2007","journal-title":"J. Raman Spectrosc."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1006\/jssc.1998.8087","article-title":"In situ Coupled Raman and Impedance Measurements of the Reactivity of Nanocrystalline SnO2 versus H2S","volume":"143","author":"Pagnier","year":"1999","journal-title":"J. Solid State Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/S0925-4005(00)00598-0","article-title":"Reactivity of SnO2-CuO Nanocrystalline Materials with H2S: A Coupled Electrical and Raman Spectroscopic Study","volume":"71","author":"Pagnier","year":"2000","journal-title":"Sens. Actuators B Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1016\/S0925-4005(01)00938-8","article-title":"Tungsten Oxide Reactivity Versus CH4, CO and NO2 Molecules Studied by Raman Spectroscopy","volume":"81","author":"Boulova","year":"2001","journal-title":"Sens. Actuators B Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1272","DOI":"10.1002\/jrs.1548","article-title":"In situ Raman Spectroscopy Study of NO2 Adsorption onto Nanocrystalline Tin(IV) Oxide","volume":"37","author":"Sergent","year":"2006","journal-title":"J. Raman Spectrosc."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"13825","DOI":"10.1021\/jp408303p","article-title":"Thermal Effects Associated With the Raman Spectroscopy of WO3 Gas-Sensor Material","volume":"117","author":"Ahmido","year":"2013","journal-title":"J. Phys. Chem. A"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"015106","DOI":"10.1088\/1361-6463\/aa98fe","article-title":"Blue- and Red-Shifts of V2O5 Phonons in NH3 Environment by In Situ Raman Spectroscopy","volume":"51","author":"Akande","year":"2018","journal-title":"J. Phys. D Appl. Phys."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/0167-2738(95)00112-J","article-title":"Correlations Between Structural and Electrical Properties of BaCeO3 Studied by Coupled In-Situ Raman Scattering and Impedance Spectroscopy","volume":"78","author":"Loridant","year":"1995","journal-title":"Solid State Ionics"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"7330","DOI":"10.1039\/c0cp02050h","article-title":"In Situ Raman spectroscopy of H2 Interaction with WO3 Films","volume":"13","author":"Ou","year":"2011","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"015705","DOI":"10.1088\/0957-4484\/23\/1\/015705","article-title":"Interaction of Hydrogen With ZnO Nanopowders\u2014Evidence of Hydroxyl Group Formation","volume":"23","author":"Wong","year":"2012","journal-title":"Nanotechnology"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.snb.2006.10.013","article-title":"Interaction of Nanocrystalline Tin Oxide Powder with NO2: A Raman Spectroscopic Study","volume":"126","author":"Sergent","year":"2007","journal-title":"Sens. Actuators B Chem."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"20761","DOI":"10.1039\/C8NR05649H","article-title":"High Selectivity of Sulfur-Doped SnO2 in NO2 Detection at Lower Operating Temperatures","volume":"10","author":"Xu","year":"2018","journal-title":"Nanoscale"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"S\u00e4nze, S., and Hess, C. (2012). Operando Spectroscopic Study of the EtOH Gas Sensing Mechanism of In2O3. IMCS Proc., 613\u2013615.","DOI":"10.5162\/IMCS2012\/7.3.1"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"25603","DOI":"10.1021\/jp509068s","article-title":"Ethanol Gas Sensing by Indium Oxide: An Operando Spectroscopic Raman-FTIR Study","volume":"118","author":"Hess","year":"2014","journal-title":"J. Phys. Chem. C"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Berka, S., Fleischer, V., and Hess, C. (2019). Shining Light on Indium Oxide Gas Sensors at Work: A Combined Operando Raman\/UV-Vis\/FT-IR Spectroscopic Study. MDPI Proc., 14.","DOI":"10.3390\/proceedings2019014011"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1497","DOI":"10.1021\/acssensors.9b00521","article-title":"Direct Operando Spectroscopic Observation of Oxygen Vacancies in Working Ceria-Based Gas Sensors","volume":"4","author":"Elger","year":"2019","journal-title":"ACS Sens."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1066","DOI":"10.1016\/j.apcatb.2018.06.058","article-title":"Unravelling the Mechanism of NO and NO2 storage in Ceria: The Role of Defects and Ce-O Surface Sites","volume":"237","author":"Filtschew","year":"2018","journal-title":"Appl. Catal. B"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"19493","DOI":"10.1021\/jp906328z","article-title":"In(OH)3 and In2O3 Micro\/Nanostructures: Controllable NaOAc-Assisted Microemulsion Synthesis and Raman Properties","volume":"113","author":"Yin","year":"2009","journal-title":"J. Phys. Chem. C"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"9022","DOI":"10.1021\/jp1017423","article-title":"Hydrogen on In2O3: Reducibility, Bonding, Defect Formation, and Reactivity","volume":"114","author":"Bielz","year":"2010","journal-title":"J. Phys. Chem. C"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"150","DOI":"10.1016\/j.cplett.2005.05.125","article-title":"Photoluminescence and Micro-Raman Scattering in ZnO Nanoparticles: The Influence of Acetate Adsorption","volume":"411","author":"Yang","year":"2005","journal-title":"Chem. Phys. Lett."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"8050","DOI":"10.1021\/jp071248e","article-title":"In Situ Investigation of Carboxylate Adsorption at the Fluorite\/Water Interface by Sum Frequency Spectroscopy","volume":"111","author":"Moore","year":"2007","journal-title":"J. Phys. Chem. C"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"20834","DOI":"10.1021\/acs.jpcc.7b06643","article-title":"Raman Spectra of Polycrystalline CeO2: A Density Functional Theory Study","volume":"121","author":"Schilling","year":"2017","journal-title":"J. Phys. Chem. C"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"2909","DOI":"10.1021\/acs.jpcc.8b00027","article-title":"Real-Time Observation of the Defect Dynamics in Working Au\/CeO2 Catalysts by Combined Operando Raman\/UV-Vis Spectroscopy","volume":"122","author":"Schilling","year":"2018","journal-title":"J. Phys. Chem. C"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"2957","DOI":"10.1021\/cr980133r","article-title":"Ultrasensitive Chemical Analysis by Raman Spectroscopy","volume":"99","author":"Kneipp","year":"1999","journal-title":"Chem. Rev."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"104316","DOI":"10.1063\/1.3264669","article-title":"High Surface-Enhanced Raman Scattering Activity from Au-Decorated Individual and Branched Tin Oxide Nanowires","volume":"106","author":"Jiang","year":"2009","journal-title":"J. Appl. Phys."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"354","DOI":"10.1016\/j.cplett.2005.04.071","article-title":"Synthesis of Au@Pd Core-Shell Nanoparticles With Controllable Size and Their Application in Surface-Enhanced Raman Spectroscopy","volume":"4","author":"Hu","year":"2005","journal-title":"Chem. Phys. Lett."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"2522","DOI":"10.1039\/b100553g","article-title":"Nanosized Tin Dioxide: Spectroscopic (UV\u2013VIS, NIR, EPR) and Electrical Conductivity Studies","volume":"3","author":"Popescu","year":"2001","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"4820","DOI":"10.1039\/c0cs00044b","article-title":"Resonance Raman and Surface- and Tip-Enhanced Raman Spectroscopy Methods to Study Solid Catalysts and Heterogeneous Catalytic Reactions","volume":"39","author":"Kim","year":"2010","journal-title":"Chem. Soc. Rev."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"3386","DOI":"10.1021\/acs.jpcc.7b10518","article-title":"Operando Multi-Wavelength and Time-Resolved Raman Spectroscopy: Structural Dynamics of a Supported Vanadia Catalyst at Work","volume":"122","author":"Waleska","year":"2018","journal-title":"J. Phys. Chem. C"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/23\/5075\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:36:11Z","timestamp":1760189771000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/23\/5075"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,11,20]]},"references-count":49,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2019,12]]}},"alternative-id":["s19235075"],"URL":"https:\/\/doi.org\/10.3390\/s19235075","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,11,20]]}}}