研究目的
To investigate the effect of relative humidity on the ammonia sensing performance and adsorption kinetics of electrospun SnO2 nanofibers at room temperature.
研究成果
SnO2 nanofibers are effective for room-temperature ammonia sensing, with performance enhanced by humidity due to competitive adsorption. Pseudo-first order kinetics best fit low ammonia concentrations, while Elovich model fits high concentrations, indicating multilayer adsorption at high humidity levels. This suggests potential for medical and industrial applications but requires further optimization for varying environmental conditions.
研究不足
The study is limited to room temperature conditions and humidity levels up to 70%; higher humidity or temperatures were not explored. The sensor performance may be affected by condensation at high humidity. The kinetic models assume specific adsorption behaviors that may not fully capture all surface interactions.
1：Experimental Design and Method Selection:
The study involved synthesizing SnO2 nanofibers via electrospinning and evaluating their ammonia sensing properties under varying humidity levels. Theoretical models (pseudo-first order and Elovich) were used for kinetic analysis.
2：Sample Selection and Data Sources:
SnO2 nanofibers were prepared from PVA and SnCl4·5H2O solutions. Ammonia gas concentrations (20-140 ppm) and relative humidity levels (0-70%) were controlled.
3：List of Experimental Equipment and Materials:
Materials included polyvinyl alcohol (PVA), tin(IV) chloride pentahydrate (SnCl4·5H2O), deionized water, dimethyl formamide (DMF), aluminum foil, interdigitated microelectrodes, nitrogen gas, ammonia gas. Equipment included electrospinning setup, electrical furnace, X-ray diffractometer (Rigaku XRD diffractometer with CuKα radiation), scanning electron microscope (SEM), stainless steel test chamber, mass flow controllers (Alicat Scientific, Inc.), Keithley model 617 electrometer, IEEE 488 data acquisition interface.
4：Experimental Procedures and Operational Workflow:
SnO2 nanofibers were synthesized by electrospinning PVA/SnCl4·5H2O solution, calcinated at 500°C, characterized by XRD and SEM. Sensing tests involved spin-coating nanofibers onto electrodes, exposing to ammonia in a chamber with controlled humidity, and monitoring current changes at
5：5 V bias. Data Analysis Methods:
Sensitivity, response time, and recovery time were calculated. Kinetic models (pseudo-first order and Elovich) were fitted to adsorption data using correlation coefficients.
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