The RMG-generated model has 19 gas-phase species, 13 adsorbates, and 80 elementary reactions. Of the 13 adsorbates, CH 4 *, H 2 O*, CO 2 *, H 2 * were considered to be physisorbed, which required treatment as a 2D gas for partition function calculations in Section 2.2. The complete mechanism is also included in this paper's supplementary information as a Cantera input YAML file.