Pt-decorated hierarchical SiC nanofibers constructed by intertwined SiC nanorods for high-temperature ammonia gas sensing

In this work, novel hierarchical SiC nanofibers (HSiC) constructed from intertwined SiC nanorods were fabricated through electrospinning and catalyst-assisted pyrolysis routes. HSiC possessed a high surface area of 108.7 m(2) g(-1) and an interconnected porous structure. Platinum nanoparticles with a size of 2-3 nm were homogeneously deposited onto SiC nanorods (Pt/HSiC) via an ethylene glycol reduction method. When applied to detect 500 ppm NH3 at 500 degrees C, the sensor based on Pt/HSiC demonstrated a sensitivity of 9.1% and a short response/recovery time of 2 s/5 s. Moreover, the sensor exhibited a low detection limit of 1 ppm NH3 and excellent repeatability. The outstanding performance is attributed to the hierarchically interconnected macro-meso-porous structure, which provides more effective active sites and facilitates gas diffusion. A proposed mechanism for the increasing resistance in an NH3 atmosphere was based on the stronger spill-over mechanism and dipolar layer effect. The successful synthesis of HSiC may provide a potential catalyst support for applications in high-temperature and corrosive environments.