Understanding the effect of Ni cluster size on methane activation and dehydrogenation

The cluster size of the active metal of the catalyst has great effect on the carbon deposits during the dry reforming of methane. In this paper, the effect of active metal cluster size on methane activation and dehydrogenation is specifically studied. Three cluster models of Ni4, Ni9, and Ni16 are applied to study and simulate the activation and dehydrogenation process of CH4 on Ni clusters of different sizes. It is found that the adsorption energy of CH4 on Ni clusters increases with the increase of cluster size, but it is fairly close. The adsorption energies of CH3, CH2, CH and C are the largest on Ni9. In this process, electrons are always transferred from Ni clusters to adsorbents, and the amount of electron transfer is proportional to the adsorption energy. In the CH4 dehydrogenation process, Ni16 showed the most excellent activity and anti-carbon performance.