Investigation on the catalytic activity and Na tolerance performance of rare earth element decorated ZSM-5 zeolite: a first-principle study

Abstract

As an important industrial catalytic material, ZSM-5 zeolites are still facing durability issues. The long-time exposure among high temperature steam during the catalytic reaction becomes the main drawback for ZSM-5 zeolite application in industry. In this study, we investigate the effects of rare-earth-ions (La, Ce, Nd, Sm, Gd, and Dy) doping on the catalytic activity and hydrothermal stability of ZSM-5 zeolites based on density functional theory. The results demonstrate that the introduced rare-earth-ions prefer to adsorb on the top of Al atom (T12 site). The Milliken charge transfer and electron density difference confirm the strong electrostatic interactions between the ZSM-5 zeolites and rare-earth-ions. The activation reaction of butene is investigated to estimate the catalytic activity of rare-earth-ion doped ZSM-5. The results demonstrate that La and Sm doped ZSM-5 zeolites exhibit superior performance on butene activation. In addition, rare-earth-ions decoration show enhanced sodium tolerance performance with decreased affinity toward Na during the catalytic process. This study demonstrated that the modification of rare-earth-ions can effectively improve the hydrothermal stability and catalytic activity of ZSM-5 zeolites.