The variety of carbon-metal bonds inside Cu⁺-ZSM-5 zeolites: A density functional theory study

Large-scale density functional theory calculations (DFT) found various types of binding of an unsaturated hydrocarbon (C₂H₂ and C₂H₄) to a ZSM-5 zeolite extraframework copper cation. We employed the DFT calculations based on the B3LYP functional to obtain local minima of an unsaturated hydrocarbon adsorbed on one or two copper cations embedded inside ZSM-5, and then compared their stabilization energies. The DFT results show that the stabilization energies are strongly dependent on the copper coordination environment as well as configurations of two copper cations. Consequently, the inner copper-carbon bonds are influenced substantially by a nanometer-scale cavity of ZSM-5.