The dissociative adsorption of methane (CH 3 + H) on Cu(111) surface is found to be thermodynamically unfavorable, whereas it is favorable for the SACs. For all the cases studies, dissociation of methane is an endothermic phenomenon, and the values are reported in Table . We observed that the lowest activation barrier is accompanied with the most elongated C-H bond. When methane adsorbed strongly, the activation barrier is higher as a result of the formation of a stable conguration (C-M-H sigma complex) as shown in Fig. . Typical congurations of the IS, TS, and FS in case of Cu(111) and TM@Cu(111) are shown in Fig. , and the relevant data is summarized in Table . The ZPE correction is important for C-H bond due to it's large vibrational frequency. Computed ZPE for all the SACs is in range of 0.187 to 0.191 eV, which is in agreement with the experimental (0.21 eV) value.