Energy Barrier Modulation vs Kinetic Acceleration: Tailoring WO3 Nanofibers for Trace-Level Mustard Gas Simulant Detection

Document Type

Article

Publication Date

6-11-2026

Department

Department of Chemical Engineering

Abstract

Detection of chemical warfare agents (CWAs) such as sulfur mustard gas is essential for protecting warfighters and first responders. In this work, tungsten oxide (WO3) nanofibers were defect-engineered via silver (Ag) decoration and strontium (Sr) doping to enhance the sensing performance toward 2-chloroethyl ethyl sulfide (2-CEES), a sulfur mustard simulant. The 2 at%Ag-WO3 (AW2) and 1 at % Sr-WO2.72 (SW4) nanofibers achieved experimental detection of 2-CEES at 100 ppb, and SW4 was estimated to have a theoretical detection limit of 55 ppb. The sensing mechanism was elucidated through energy barrier analysis, rate constant/activation energy correlation, and density functional theory (DFT) calculation. The enhanced 2-CEES sensing performance enabled by Ag decoration was mainly attributed to a larger change in the effective barrier height between air and N2 atmospheres (ΔEb), whereas the performance enhancement from Sr doping arose from an oxygen-vacancy-enriched structure, faster reaction kinetics, and stronger 2-CEES adsorption. By demonstrating trace-level detection of 2-CEES and unraveling the distinct contributions of electronic modulation and reaction kinetics, this study highlights AW2 and SW4 nanofibers as promising 2-CEES sensing materials and provides mechanistic guidance for the rational design of advanced metal oxide gas sensors.

Publication Title

ACS Sensors

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