A significantly enhanced activity in NOx reduction by methane was observed when a small amount (5 wt %) of Pt/Al2O3 or Mn3O4 was mechanically mixed with In/ZSM-5 in both dry and wet lean conditions. The highest NO conversions to nitrogen were over 98% with these novel multifunctional catalysts at 500 degrees C in dry conditions. The same activity was not reached with bimetallic Pt-In/ZSM-5, which showed the benefit of macroscale separation of active compounds (In separated from Pt or Mn3O4) in CH4-SCR. Neither Pd/Al2O3 nor Ir/Al2O3 was able to promote NOx reduction as a mechanical mixture with In/ZSM-5. Based on the surface intermediate (FTIR) and kinetic studies, a reaction mechanism on the binary combination of In/ZSM-5 and Pt/Al2O3 was defined. The presence of NO2 enhanced the formation of partially oxidized, nitrogen-free, and nitrogen-containing methane derivates. In the key reaction, the adsorbed NH2 (amine) and NO form N-2 on In/ZSM-5. Pt/Al2O3 enhanced NO2 formation, methane oxidation, CO oxidation, and surprisingly the reduction step to nitrogen. The increased formation of N2O in two-component reactors revealed that N-2 was formed on In/ZSM-5 by HC-SCR reactions but also on Pt/Al2O3 by NO decomposition. The microkinetic model, based on defined surface reactions on separated indium and platinum sites on different supports, was able to predict all observed reactant and product concentrations in steady-state CH4-SCR.