Simplistic representation of the processes that occur in our experiments. Panel a-d show the proposed Langmuir–Hinshelwood reaction that creates CO₂ in our experiments. Panels in the bottom row schematically show the structure or phase in which the formed products end up after formation, given a certain experimental temperature. ^(*)Molecular oxygen is not formed through the depicted reaction, for details see Sects. 4.1 and 4.4.