Optimization of synthesis conditions and sensing performance of electrospun NiFe2O4 nanofibers for H2S and NO2 detection

We evaluated the combined impact of process parameters, including electrospun time, applied voltages, and needle tip-to-collector distances, on the gas-sensing characteristics of on-chip sensors based on NiFe2O4 nanofibers fabricated using a conventional electrospinning approach. A porous structure and many nanograins were present in NiFe2O4 nanofibers with diameters of 30–100 nm. The sensor response for both H2S and NO2 gas reached its peak after 30 min of electrospinning. Stronger applied voltages and shorter spinning distances resulted in a higher sensor response to reducing H2S gas, whereas weaker applied voltages and longer spinning distances led to a higher sensor response to oxidizing NO2 gas. The NiFe2O4 nanofiber sensor showed a high response to 1 ppm H2S and 10 ppm NO2 of around 4.3 with quick response time (11 and 27 s) and slow recovery time (278 and 303 s), respectively, at the operating temperature of 350 °C. The NiFe2O4 nanofiber sensor also displayed outstanding stability and high selectivity. These gas-sensing results pointed to NiFe2O4 nanofibers as a potentially effective substitute for creating the perfect platform for H2S and NO2 detection. © 2022 Elsevier B.V.