High performance tube sensor based on PANI/Eu³⁺ nanofiber for low-volume NH₃ detection

A novel polyaniline (PANI)/Eu³⁺ nanofiber sensing film was prepared in the presence of Eu(NO₃)₃ which serves as structure-directed agent. The morphological, component, crystallinity and electrochemical properties were carried out by using Scanning Electron Microscope (SEM), Energy-Dispersive X-ray (EDX), Fourier Transform Infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Brunauer-Emmett-Teller (BET) techniques. The results indicated the nanofiber-like network with porous structure appeared in the PANI embedded by Eu³⁺ ions, thereby leading to large specific surface area. Furthermore, the PANI/Eu³⁺ nanofibers were grown onto the inner wall of capillary glass to form the tube sensor. By the sensing measurements, this tube sensor enabled the detection of low-volume (0.3 mL) NH₃ for response 435% at concentration of 0.25 ppm with a short response time (5 s) and recovery time (5 s), and the performances of reproducibility and selectivity were also excellent. The above results demonstrated the potential application of PANI/Eu³⁺ tube sensor for low-volume NH₃ gas.