Use of Nanoporous FeOOH as a Catalytic Support for NaHCO3 Decomposition Aimed at Reduction of Energy Requirement of Na2CO3/NaHCO3 Based CO2 Separation Technology

CO 2 capture is typically a costly operation, usually due to the energy required for regeneration of the capture medium. Na 2 CO 3 is one potential capture medium with the potential to decrease this energy requirement. Extensively researched as a potential sorbent for CO 2, Na 2 CO 3 is well-known for its theoretically low energy requirement, due largely to its relatively low heat of reaction compared to other capture technologies. Its primary pitfalls, however, are its extremely low reaction rate during sorption and slow regeneration of Na 2 CO 3 . Before Na 2 CO 3 can be used as a CO 2 sorbent, it is critical to increase its reaction rate. In order to do so, this project studied nanoporous FeOOH as a potential supporting material for Na 2 CO 3 . Because regeneration of the sorbent is the most energy-intensive step when using Na 2 CO 3 for CO 2 sorption, this project focused on the decomposition of NaHCO 3, which is equivalent to CO 2 desorption. Using Brunauer–Emmet–Teller analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, magnetic susceptibility tests, and Mössbauer spectroscopy, we show FeOOH to be thermally stable both with and without the presence of NaHCO 3 at temperatures necessary for sorption and regeneration, up to about 200 °C. More significantly, we observe that FeOOH not only increases the surface area of NaHCO 3, but also has a catalytic effect on the decomposition of NaHCO 3, reducing activation energy from 80 to 44 kJ/mol. This reduction in activation energy leads to a significant increase in the reaction rate by a factor of nearly 50, which could translate into a substantial decrease in the cost of using Na 2 CO 3 for CO 2 capture.