They found that the first dehydrogenation step, that is, producing COOH* or HCOO*, is most facile on under-coordinated sites of reactive metals on the left of the transition metals in the periodic table, Re, Ru, and Os. The second dehydrogenation step, that is, the elimination of CO2, is however, most driven on highly coordinated sites of the inert metals on the right of the transition metals such as Cu, Ag, and Au.