Authors: R. Shende, A. Vats, Z. Doorenbos, D. Kapoor, J. Puszynski
Affilation: South Dakota School of Mines & Technology, United States
Pages: 692 - 695
Keywords: pyrophoric nanoparticles, alpha-Fe, Fe-oxalate, nanorods, nanowires
The formation of pyrophoric Fe-nanoparticles from Fe(II)-oxalate decomposition under H2 atmosphere was the main objective of this research. Iron oxalate was synthesized by controlled nucleation process involving addition of oxalic acid in the FeCl2.2H2O solution followed by separation and drying. The oxalate was characterized by Fourier Transform Infrared (FTIR) spectroscopy, powdered x-ray diffraction, and Transmission Electron Microscopy (TEM). As-synthesized oxalate was decomposed in a quartz tubular reactor at 450-520oC and reduced with a gases mixture containing 5 vol% of H2 in N2. After exposing it to air at room temperature, the fine Fe particles generated a temperature of about 800oC in less than 1 sec. In other approach, Fe-oxalate was synthesized using solid state synthesis method involving formation of a slurry containing oxalic acid, FeCl2 and polyethylene glycol surfactant. The slurry was diluted with de-ionized water, sonicated, and centrifuged to recover the precipitate. TEM images of this oxalate indicated nanorod like morphology with the diameter of about 20 nm and length of 70-80 nm. Pyrophoric behavior was confirmed by decomposing and reducing the oxalate nanorods at 500oC followed by oxidizing them in air at ambient conditions. Synthesis of the pyrophoric -Fe nanoparticles from Fe-oxalate nanowires will be discussed as well.