Achieving One Part Per Billion Hydrogen Sulfide (H₂S) Level Detection through Optimizing Composition and Crystallinity of Gold-Decorated Tungsten Trioxide (Au-WO₃) Nanofibers

Abstract

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 lowresource settings. Gold doped/decorated tungsten trioxide (Au-WO 3 ) nanofibers with various compositions and crystallinities were synthesized to optimize H 2 S-sensing performance. Systematically experimental results demonstrated the ability to detect 1 ppb H 2 S with a response value (R air /R gas ) of 2.01 using a 5 at % Au-WO 3 nanofibers with average grain sizes of around 15 nm. Additionally, energy barrier difference of sensing materials in air and nitrogen (ΔE b ) 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 H 2 S detection mechanism.

Synthesis and Characterization of Composite WO3 Fibers/g-C3N4 Photocatalysts for the Removal of the Insecticide Clothianidin in Aquatic Media

“…The average crystallite size for WOFs was calculated by using the Scherrer equation for the aforementioned 2θ values and found to be 15.80 nm [64][65][66][67]. These findings are consistent with the crystallographic features of electrospun WO 3 fibrous materials reported in the literature, as they all exhibited a monoclinic crystalline phase with average crystallite sizes ranging from 13.00 to 26.50 nm [59,[66][67][68]. The chemical composition of the synthesized pristine and composite materials was studied through ATR-FTIR spectroscopy.…”

“…43-1035, confirming the monoclinic crystalline phase of WOFs with the P21/n space group [ 59 , 60 , 61 , 62 , 63 ]. The average crystallite size for WOFs was calculated by using the Scherrer equation for the aforementioned 2θ values and found to be 15.80 nm [ 64 , 65 , 66 , 67 ]. These findings are consistent with the crystallographic features of electrospun WO 3 fibrous materials reported in the literature, as they all exhibited a monoclinic crystalline phase with average crystallite sizes ranging from 13.00 to 26.50 nm [ 59 , 66 , 67 , 68 ].…”