Detection of hazardous gas using multidemensional porous iron oxide nanorods-decorated carbon nanoparticles

Multidimensional porous iron oxide (Fe2O3) nanorods-decorated carbon nanoparticles (MPFCNPs) were fabricated using a dual-nozzle electrospray, thermal stirring, and heat treatment. Polypyrrole (PPy) NPs with FeOOH nanorods were synthesized by electrospraying Fe(3+) ions, which were adsorbed on the PPy NP surface; the adsorbed Fe(3+) ions reacted with NaOH to create FeOOH nuclei, and then followed thermal stirring grow nanorods without aggregation. MPFCNPs were fabricated through heat treatment, with the porous structure created in the Fe2O3 nanorods by hydroxyl group decomposition. The size of the MPFCNPs and the length of the porous Fe2O3 nanorods were controlled by the PPy NP template and concentration of initiator solution, respectively. The MPFCNPs were then utilized as a chemical sensor transducer for NO2 gas detection at room temperature. The response of the MFPCNP sensor was highly sensitive, displaying a minimum detectable level of 1 ppm; this detection level is lower than that of organic-inorganic hybrid sensors. Moreover, sensitivity also improved with decreasing the diameter of MPFCNPs and increasing Fe2O3 nanorod length. The enhanced sensitivity was attributed to the larger surface area presented by the particle size and the porous structure.