A recent case study in methane catalytic combustion on platinum demonstrates the heterogeneous catalysis functionality. It addresses extensive updates to the original release of RMG-Cat. Among those is the new platinum thermochemistry database which is larger and more accurate than the original nickel database and has the advantage of including nitrogen-containing adsorbates. Another important new feature is the ability to explore heterogeneous and gas-phase reactions simultaneously, as with that the resulting microkinetic models can provide an implication of when catalytic surfaces lead to radical chemistry in the gas phase.