Synthesis and characterization of hybrid NiO/CeO2 p-n heterojunction nanofibers for room temperature ammonia sensing application

Abstract

The development of room temperature chemiresistive NH3 gas sensors with superior selectivity and stability is always an uphill task to solve. This work describes the synthesis and characterization of NiO/CeO2 p-n heterojunction nanofiber assembly using a facile electrospinning method. Systematic studies are conducted using SEM, XRD, XPS, and TEM to examine the microstructure and morphology. The electro spun nanofibers offer high surface area of NiO/CeO2 p-n heterojunction composite sensor with an average fiber diameter of ∼125 ± 20 nm, regulated morphology, and interconnectivity through junction formation. Under ambient temperature, the sensing performance for 10–100 ppm NH3 gas is investigated. The increased specific surface areas, formations of multiple NiO/CeO2 bridging point contacts are responsible for the improved gas sensitivity. Experiments reveal that NiO/CeO2 hybrid nanofiber sensor outperforms the pure NiO NF sensor for NH3 sensing, in addition to superior selectivity, good stability and quick response/recovery time. Gas sensors based on NiO/CeO2 are anticipated to become a viable option for the detection of ammonia in breathed gas of sufferers with gastrointestinal or renal disorders in the future due to their flexibility, room temperature operation, and good reaction to ammonia.