Large-Scale Nanofiber Manufacturing| Electrospun FeVO4 nanofibers-based gassensor with high selectivity and fastresponse towards n-butanol

Prof. Dong Xiangting, Assoc. Prof. Shao Hong & Assoc. Prof. Wang Tianqi from Changchun University of Science and Technology: Electrospun FeVO4 Nanofiber Gas Sensor with High Selectivity and Fast Response to n-Butanol

In recent years, detection of toxic gases like NO2, H2S, and n-butanol has gained increasing attention. n-Butanol, a common industrial solvent and chemical synthesis intermediate, is widely used in chemical and pharmaceutical fields. However, being toxic and highly flammable, prolonged exposure may irritate skin and eyes, even paralyze the nervous system, causing serious health issues. Therefore, developing novel n-butanol gas-sensitive materials is crucial for personnel and environmental safety.

Recently, Prof. Dong Xiangting, Assoc. Prof. Shao Hong and Assoc. Prof. Wang Tianqi's team at Changchun University of Science and Technology published their latest research "Electrospun FeVO4 nanofibers-based gas sensor with high selectivity and fast-response towards n-butanol" in Sensors and Actuators: B. Chemical.

The researchers synthesized 1D FeVO4 nanofibers (Fig.1) via a simple one-step electrospinning method combined with calcination, first applying them in gas sensing. At optimal working temperature, FeVO4 nanofibers showed high selectivity and fast response to n-butanol, with response/recovery times of 3s and 14s respectively for 100ppm n-butanol. This study holds significance for gas sensing technology development, providing new approaches for monitoring VOCs like n-butanol.

Fig.1: Schematic of FeVO4 nanofiber preparation process

After calcining FeVO4 precursors at 450°C, 500°C, and 550°C for 2h, nanofiber diameters decreased with rougher surfaces, caused by organic elimination, inorganic salt decomposition, and gas release during FeVO4 crystallization. Fiber morphology disappeared above 600°C.

Fig.2: SEM images of (a,b) FeVO4 precursors and samples calcined at (c,d)450°C, (e,f)500°C, (g,h)550°C, (i,j)600°C, (k,l)650°C for 2h

XRD patterns confirmed successful synthesis of triclinic FeVO4 above 550°C. XPS verified Fe2+, Fe3+, V5+, and V4+ presence in nanofibers, as ammonia released during calcination reduced some Fe3+ and V5+ to Fe2+ and V4+.FeVO4 nanofibers exhibited more oxygen vacancies and adsorbed oxygen. Oxygen vacancies promoted oxygen molecule adsorption, creating more active sites. Increased oxygen vacancies also enhanced adsorbed oxygen and target gas molecules, improving sensitivity.

Fig.3: XRD patterns of FeVO4 precursors calcined at different temperatures, crystal structure of triclinic FeVO4, and XPS spectra

As shown in Fig.4, at optimal 300°C working temperature, FeVO4 nanofiber sensors demonstrated good n-butanol selectivity compared to FeVO4 (650) samples. Sensitivity increased with n-butanol concentration until leveling off at 80ppm. For ≤100ppm, sensitivity showed excellent linearity with concentration. At 100ppm, the sensor exhibited stable response/recovery with fast speeds (3s response, 14s recovery), attributed to FeVO4's unique 1D structure, large surface area, abundant oxygen vacancies and adsorbed oxygen. The sensor also showed good stability.

Fig.4: Gas sensing performance of FeVO4 nanofibers

This work demonstrates FeVO4 nanofibers' potential in gas sensing, providing theoretical and technical support for developing other fiber-based gas sensors. Master students Hao Lu and Li Ji are co-first authors. This research was supported by National Natural Science Foundation and Jilin Provincial Natural Science Foundation.