Inhibition of Reaction Layer Formation on MgO(100) by Doping with Trace Amounts of Iron
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- Queens College, City University of New York, NY (United States)
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- University of Chicago, IL (United States)
- Queens College, City University of New York, NY (United States); Earth and Environmental Sciences, Graduate Center, City, University of New York, NY (United States)
Despite extensive research on MgO’s reactivity in the presence of CO2 under various conditions, little is known about whether impurities incorporated into the solid, such as iron, enhance or impede hydroxylation and carbonation reactions. The purity of the MgO required for the successful implementation of MgO looping as a direct air capture technology affects the deployment costs. With this motivation, we tested how incorporated iron impacts MgO (100) reactivity and passivation layer formation under ambient conditions by using atomic force microscopy, electron microscopy, and synchrotron-based X-ray scattering. Based on electron microprobe analysis, our MgO samples were 0.5 wt % iron, and Mössbauer spectroscopy results indicated that 70% of the iron is present as Fe(II). We find that even these low levels of iron dopants impeded both the hydroxylation at various relative humidities (10%, 33%, 75%, and >95%) and carbonation in CO2 (33%, 75%, and >95%) on the (100) surface. Crystalline reaction products were formed. Reaction layers on the sample were easily removed by exposing the sample to deionized water for 2 min. Overall, our findings demonstrate that the presence of iron dopants slows the reaction rate of MgO, indicating that MgO without incorporated iron is preferable for mineral looping applications.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Queens College, City University of New York, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
- Grant/Contract Number:
- AC02-06CH11357; AC05-00OR22725; SC0019108
- OSTI ID:
- 2515661
- Journal Information:
- Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 7 Vol. 129; ISSN 1932-7447
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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