H2 detection mechanism in chemoresistive sensor based on low-cost synthesized WO3 nanorods

SENSORS AND ACTUATORS B-CHEMICAL

卷:348

Article

Mineo, G.^1,2  Moulaee, K.³  Neri, G.³  Mirabella, S.^1,2  Bruno, E.^1,2 

[1] Univ Catania, Dipartimento Fis & Astron Ettore Majorana, Via S Sofia 64, I-95123 Catania, Italy

[2] Univ Catania, CNR IMM, Via S Sofia 64, I-95123 Catania, Italy

[3] Univ Messina, Dipartimento Ingn, I-98158 Messina, Italy

关键词: Tungsten-trioxide;    Hydrothermal;    Nanostructures;    Gas sensor;    Hydrogen sensing;   

DOI  :  10.1016/j.snb.2021.130704

来源: Elsevier

【 摘 要 】

Nanostructured WO3 represents a promising material for fast and reliable molecular hydrogen detection through chemo-resistive effect. Here, an extended experimental investigation of WO3-H-2 interaction is presented and modeled. A powder of WO3 nanorods (400 nm long, 50 nm large) is produced by hydrothermal technique and drop casted on Pt interdigitated electrode. H-2 sensing tests at different concentrations (2000-50,000 ppm) and temperatures (250-400 degrees C) are reported. Scanning Electron Microscopy (SEM), X-ray Diffraction analysis (XRD), and electrical measurements were performed. The response and recovery kinetics of H-2 sensing are carefully described by using a two-isotherms Langmuir model, and kinetics barriers for WO3-H-2 interaction are evaluated. Two microscopic processes lead to gas detection. A fast process (shorter than 4 s) is attributed to H-2 interaction with adsorbed oxygen at WO3 nanorods surface. A slow process (20-1000 s), with activation energy of 0.46 eV, is attributed to oxygen vacancy generation in WO3. H intercalation in WO3 is ruled out. The recovery of WO3 after H-2 exposure is also modeled. The chemo-resistive effect leading to H-2 sensing by WO3 is explained through the above processes, whose kinetic barriers have been quantified. These data open the route for the development of fast, sensitive, and low-temperature operating H-2 sensors based on WO3.

【 授权许可】

Free