Achieving One
Part Per Billion Hydrogen Sulfide (H2S) Level Detection
through Optimizing Composition and Crystallinity
of Gold-Decorated Tungsten Trioxide (Au-WO3) Nanofibers
posted on 2024-01-12, 23:29authored byBingxin Yang, Dung Thi Hanh To, Emily Resendiz Mendoza, Nosang V. Myung
As
a common environmental pollutant and an important breath biomarker
for several diseases, it is essential to develop a hydrogen sulfide
gas sensor with a low-ppb level detection limit to prevent harmful
gas exposure and allow early diagnoses of diseases in low-resource
settings. Gold doped/decorated tungsten trioxide (Au-WO3) nanofibers with various compositions and crystallinities were synthesized
to optimize H2S-sensing performance. Systematically experimental
results demonstrated the ability to detect 1 ppb H2S with
a response value (Rair/Rgas) of 2.01 using a 5 at % Au-WO3 nanofibers
with average grain sizes of around 15 nm. Additionally, energy barrier
difference of sensing materials in air and nitrogen (ΔEb) and power law exponent (n) were determined to be 0.36 eV and 0.7, respectively, at 450 °C
indicating that O– is predominately ionic oxygen
species and adsorption of O– significantly altered
the Schottky barrier between the grain. Such quantitative analysis
provides a comprehensive understanding of H2S detection
mechanism.