Tailored Fe3C-derived carbons with embedded Fe nanoparticles for ammonia adsorption

Carbide-derived carbons are synthesized by chlorination of Fe3C at temperatures ranging from 200 to 1000 °C. The complex extraction method of Fe from Fe3C at moderate temperatures (600 °C) allows for the tailored inclusion of FeCl2, FeCl3, or Fe nanoparticles in the resulting CDC by controlling the synthesis conditions and post-treatment methods. In this study, we extend the synthesis to other temperatures in order to understand the role of chlorination temperature on the physical and textural properties of the resulting CDC. We also examine the activity of Fe3C-CDCs with embedded FeCl3 nanoparticles for ammonia adsorption. Materials synthesized at 600 °C show exceptional results in ammonia breakthrough experiments, and achieved dynamic loadings of 1.88 mmol g−1 at 0% relative humidity and 3.44 mmol g−1 at 75% relative humidity calculated at initial breakthrough when [NH3] > 0 ppm. NH3 temperature programmed desorption (NH3-TPD) and Fourier Transform Infrared Spectroscopy (FTIR) experiments suggest that the uptake is primarily due to ammonia complexation with FeCl3 nanoparticles under dry conditions, and additional interactions with trapped chlorine in the presence of water.