The reaction starts at the co-adsorbed state of the 4 systems, labeled as Ads. Previous studies have found the abstraction of alcoholic H as the first step. The reaction scheme is shown in Figure . In our study, we found that the transition state (TS1) corresponding to this step exists only in the case of Cu 13 with a small energy barrier of 0.49 kcal/mol. The alcoholic O-H bond length increases from 1.03 Å to 1.14 Å and alcoholic H -O (O 2 ) bond length decreases from 1.52 Å to 1.3 Å as the molecules reaches TS1 from Ads. A similar transition state was not found in the other three catalysts, as was confirmed using relaxed scan of the corresponding reaction coordinate. Any transition state optimization for them results in the Ads or Int1 state for Au rich catalyst and Cu 12 Au catalysts respectively. This reaction change leads to the formation of the intermediate, Int1 possessing a hydroperoxyl like species, AuOOH, and was found to be most stable for Cu 12 Au with -29.86 kcal/mol, followed by Cu 13 at -5.51 kcal/mol, while this step becomes endothermic for the Au rich