Comparison of our results to other experimental and theoretical studies suggest that the CO desorption rates observed are a consequence of different carbon-oxygen functional groups that are formed after O chemisorbs on the surface. Tremblay et al. showed the presence of at least two functional groups on a carbon surface and further studies have shown the presence of multiple functional groups on the surface. Typical functional groups attributed to the formation of CO are ethers, semi-quinones, lactones, anhydrides, and furan/pyrone structures . A few representative functional groups that are formed on a carbon surface are shown in Figure (Supplementary Material). Although there is consensus on the broad nature of functional groups, there is disagreement on the exact functional groups being formed on the surface. The DFT results of Sun et al. and Carlsson et al. indicate that the energy barriers of CO desorption from isolated ethers and semi-quinones are greater than 1 eV. However, the presence of O adsorbed on neighboring carbon sites lowers the energy barrier significantly. The simulation results suggest that CO desorption occurs from lactone-type structures where a lactone group is surrounded by a neighboring ether structure. On a complicated surface like FiberForm, the desorption of CO can create new structures that can be further sites for CO desorption. For example, the desorption of CO from an ether-lactone-ether structure would result in a lactone-ether structure which is another reactive site for CO desorption . Thus, the CO desorption rates observed in our experiments may arise from different combinations of lactone and ether groups that are formed on the surface.