第一性原理模拟计算银-镍催化剂银覆盖率对甲烷解离吸附的影响

Methane dissociation is considered to be the rate-determining step for steam reforming of methane (SRM). Meanwhile, the successive dissociation of methane can also lead to the cock formation and catalyst deactivation. Ni-based catalyst is traditionally used in industrial SRM process. Recently, it is found that the catalyst performance can be improved by the introduction of Ag. DFT calculations are preformed to elucidate the effects of the Ag coverage on the coke resistance over Ag/Ni(100) in this paper. The adsorption energies of the CHx species and the activation energies for the elementary steps involved are obtained at the Ag coverages of 1/9 and 1/4 ML. The results showed that the low Ag content has negligible effects on the surface reactions, while with the Ag coverage increased to 1/4 ML, the Ag/Ni(100) surface is reconstructed and the energy barrier for the carbon formation is dramatically raised.