Reaction sensitivities on Rh(111) at an inlet gas stoichiometry C/O = 1.0 for CH 4 conversion and synthesis gas yields are seen in the Supporting Information. The most sensitive reaction was R5, the adsorption of CH 4 with an oxygen double bonded to the surface, seen in Table . Averaging over all inlet gas stoichiometries and metals, the most sensitive reaction was the (reversible) dissociative adsorption of O 2 , R1 from Table . Figure shows this reaction is mostly sensitive on metals that see low or no CH 4 conversion (i.e. on metals with strong oxygen binding energies) suggesting it is one of the main reactions responsible for both the shape and location of the volcano. Speeding up the rate of dissociative adsorption (and associative desorption) slows the entire system (negative sensitivity) on metals with weak carbon and strong oxygen binding energies (bottom right corner), as oxygen will fill empty surface sites before any other species can adsorb, thus blocking the entire reaction from occurring, seen in the Supporting Information. A positive sensitivity indicates O 2 adsorption is the rate limiting step on metals with both strong carbon and oxygen binding energies (bottom left corner). At such strong carbon binding energies, increasing the rate helps adsorb more oxygen to the surface. The rate of dissociative O 2 adsorption is not sensitive on metals that have high CH 4 conversion, and is extremely sensitive when CH 4 conversion decreases (around the 'cliffs' of the volcano plot). CH 4 conversion, full oxidation yield, and partial oxidation yield were all over 30% more sensitive to reaction R1 than to the next most sensitive reaction. R6, hydrogen association to CH 2 as seen in Figure , and R5, the dissociative adsorption of CH 4 with a surface oxygen seen in Figure , are the next most sensitive reactions and show similar sensitivity. While R6 is slightly more sensitive than R5, both limit methane conversion on metals with weaker carbon binding energies (to the right on the plots).