Multidimensional polypyrrole/iron oxyhydroxide hybrid nanoparticles for chemical nerve gas agent sensing application

Multidimensional FeOOH nanoneedle-decorated hybrid polypyrrole nanoparticles (PFFs) were fabricated using dual-nozzle electrospray and heat stirring process. To decorate metal oxide nanoneedles on the polypyrrole (PPy) surface, metal oxide particle-decorated PPys (E_PPy) were fabricated as starting materials. The E_PPy particles were prepared by dual-nozzle electrospray because ferric ions (Fe(3+)) dispersed on the surface reacted with hydroxide (OH(-)) ions in the collector solution without aggregation of each particles. Multidimensional hybrid PFFs with maximized surface area were then formed by heat stirring reaction in the aqueous metal precursor contained solutions. The decoration morphology of the metal oxide nanoneedles could be controlled by precursor concentration in the aqueous solution. These multidimensional hybrid PPFs were applied to nerve gas agent (DMMP) chemical sensor at room temperature with excellent sensitivity. The minimum detectable level (MDL) of PFFs was as low as 0.1 ppb, which is higher than that for a chemical sensor based on hybrid materials. This is because the metal oxide nanoneedles increase surface area and affinity to DMMP vapor.