Unraveling the role of Ni13 catalyst supported on ZrO2 for CH4 dehydrogenation: The d-band electron reservoir

The activation of C–H bonds of CH 4 is a key step for the conversion of methane to chemical commodities. Loading Ni onto ZrO 2 is regarded as a relatively efficient way to harness the beneficial electronic property and the fine dispersion of the Ni catalyst for CH 4 dissociation. Herein we demonstrate the crucial role of Ni 13 catalyst supported on ZrO 2 for the dissociation of CH 4 . The density functional theory (DFT) results show that the ZrO 2 supported Ni 13 stabilizes all species better and facilitates CH 4 activation. The stepwise dehydrogenations of CH 4 on Ni 13 -ZrO 2 (111) exhibits longer C–H bond lengths of ISs, lower E a , and smaller displacements between the detaching H and the remaining CH x fragment in TSs. In addition, they are also thermodynamically more feasible. However, without the ZrO 2 support on Ni 13 , the opposite results are obtained. Consequently, the ZrO 2 modified Ni 13 is more superior to the original Ni 13 in CH 4 dehydrogenation. The electronic analysis combining DFT calculations confirmed that the larger overlap between C 2 p and Ni 3 d , and the electron transfer of Ni→C cause the weaker C 2 p –H 1 s hybridization. In addition, the reduction of electron transfer of H→C leads to a stronger interaction between Ni and C along with a weak C–H bond. Hence, the ZrO 2 support serves as the d -band electron reservoir at Ni 13 and it is benefit to the activation of C–H bonds in CH 4 dehydrogenation.