The adsorption and hydrogenolysis of ethane on fcc-Mo2C (1 0 0) and hcp-Mo2C (1 0 1) has been studied using density functional theory calculations with the periodic slab model. We found that the reaction mechanism for ethane hydrogenolysis are basically the same on both fcc and hcp phase Mo2C catalysts, that is, C2H6 (a) -> C2H5 (a) -> CH2 (a) -> CH3 (a) -> CH4. For the rate-controlling step (C2H5 -> CH2 + CH3), the activation energy on hcp-Mo2C (1 0 1) (1.53 eV) is lower than that on fcc-Mo2C (1 0 0) (1.81 eV), which indicated that the hcp-Mo2C (1 0 1) shows higher reactivity than that of fcc-Mo2C (1 0 0). The possible reason may come form the fact that the hcp-Mo2C (1 0 1) is more open and corrugated than fcc-Mo2C (1 0 0), which results in the interaction (mainly the repulsion effect) between CH2 and CH3 at transition state is relatively weak on hcp-Mo2C (1 0 1), and thus the higher reactivity on hcp-Mo2C (101) can be expected. Moreover, it was found that the pre-adsorbed hydrogen atom can effectively reduce the barrier of C2H5 -> CH2 + CH3 on Mo2C catalysts. (c) 2013 Elsevier B.V. All rights reserved.