The surface coverages of the volcano curves of Figure shift with the binding energy of B* consistent with the rate-controlling phenomenon. At low BE B , the surface is bare. For the high γ B-A systems (blue, γ > 1.0), the surface becomes Figure demonstrates the changes due to lowering the value of δ from 1.4 eV to 0.5 eV in comparison with Figure . At low δ, the high γ B-A curves have higher TOF performance across a wide span of binding energies, but the maximum TOF B is lowered to ~10 2 s -1 . In addition, the intermediate regime of the low γ B-A plots moves to the right of the volcano plot peak at absolute binding energies of 0.5-1.3 eV, so there now exists a surface reaction/desorption limited regime. The high γ B-A curves coalesce on the desorption limited line at ~1.3 eV and onwards in Figure , meaning that these systems are nearly saturated with B* and the TOF B is solely dependent on the binding energy of B past this point.