Tu-CHS-01 - Manganese Spinels Boost Gas Sensitivity in Humid Environments

Event

EUROSENSORS 2026
2026-09-06 - 2026-09-09
Zurich

Band

Poster

Chapter

Chemical Sensors

Author(s)

R. dos Santos Theodoro, D. P. Volanti - São Paulo State University,São José do Rio Preto (Brazil), M. D’Andria, T. E. Abi-Ramia Silva, A. T. Güntner - ETH Zurich,Zurich (Switzerland)

Pages

420 - 421

DOI

10.5162/eurosensors2026/Tu-CHS-01

ISBN

978-3-910600-12-6

Price

free

Abstract

Humidity typically reduces the sensitivity of chemoresistive gas sensors, limiting their applicability in environmental monitoring, health diagnostics, and breath analysis, where volatile organic compounds (VOCs) are key target analytes [1]. Various strategies have been developed to mitigate this undesired effect, including metal-functionalized MOx, heterojunctions, and ternary oxides such as perovskite and spinel structures [2]. Here, we show that humidity-related hydroxyl species can instead enhance sensing performance rather than degrade it. ZnMn2O4 spinel nanoparticles for acetone sensing were synthesized via flame spray pyrolysis (FSP) [3–5], with the p-type Zn/Mn spinel sensor exhibiting a ~60% higher response to ppb-level acetone concentrations under humid conditions than under dry conditions, together with a theoretical limit of detection (LOD) of 600 ppt. Using X-ray absorption spectroscopy, in situ IR spectroscopy, and isotopically labeled chemisorption analysis, we demonstrate that humidity-derived surface-adsorbed hydroxyl groups actively participate in analyte oxidation, with oxidation product formation rates up to an order of magnitude higher under humidity, positioning humidity as a promoter of sensitivity, not merely a challenge to mitigate.