Surface Activity-Tuned Metal Oxide Chemiresistor: Toward Direct and Quantitative Halitosis Diagnosis

초록

Continuous monitoring of hydrogen sulfide (H2S) in human breath for early stage diagnosis of halitosis is of great significance for prevention of dental diseases. However, fabrication of a highly selective and sensitive H2S gas sensor material still remains a challenge, and direct analysis of real breath samples has not been properly attempted, to the best of our knowledge. To address the issue, herein, we introduce facile cofunctionalization of WO3nanofibers with alkaline metal (Na) and noble metal (Pt) catalystsviathe simple addition of sodium chloride (NaCl) and Pt nanoparticles (NPs), followed by electrospinning process. The Na-doping and Pt NPs decoration in WO3grains induces the partial evolution of the Na2W4O13phase, causing the buildup of Pt/Na2W4O13/WO3multi-interface heterojunctions that selectively interacts with sulfur-containing species. As a result, we achieved the highest-ranked sensing performances, that is, response (Rair/Rgas) = 780 @ 1 ppm and selectivity (RH2S/REtOH) = 277 against 1 ppm ethanol, among the chemiresistor-based H2S sensors, owing to the synergistic chemical and electronic sensitization effects of the Pt NP/Na compound cocatalysts. The as-prepared sensing layer was proven to be practically effective for direct, and quantitative halitosis analysis based on the correlation (accuracy = 86.3%) between the H2S concentration measured using the direct breath signals obtained by our test device (80 cases) and gas chromatography. This study offers possibilities for direct, highly reliable and rapid detection of H2S in real human breath without the need of any collection or filtering equipment. © 2021 American Chemical Society

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