“…It was noteworthy that the Al 2 O 3 was more dispersed after run for 150 h reaction for its peaks disappearance, as well as the Cu 0 diffraction peaks at 43.3 °, 50.3 °, 74 ° was observed rather than CuO, suggesting the occurrence of the phase transformation of CuO during the reactions. Although there was no evidence for the presence of Cu + , it could not exclude the possibility that the the acitive sites was not only Cu 0 but also Cu + and the rearrangement between them during the induced period, as in the reports [10,15]. Meanwhile, the absence of peaks corresponding to graphite carbon, which could cause the irreversible deactivation of the material, between 25° and 30° on the spent material revealed that it is hidered by the low reaction temperature, high H 2 concentration and the presence of water in the reaction medium [20].…”