Zeolite structure descriptor for guiding the synthesis of efficient titanosilicalites through matching Ti sites and framework topologies for 1-Hexene epoxidation

Abstract

Rational design of metal-containing zeolites with different framework topologies can boost catalytic performance, but the successful synthesis of metal-containing zeolites typically requires selection of suitable zeolite scaffolds. Herein, a zeolite structure descriptor (i.e., the local framework disturbance index, LFDI) is proposed to guide the design of Ti-containing zeolites by matching Ti sites and different framework topologies to enhance olefin epoxidation performance. Theoretical calculations of the incorporation of Ti metal atoms into different crystallographic T sites indicate that the BEA framework exhibits the more negative average substitution energy (-0.50 eV) than MFI and MEL frameworks due to the lowest average LFDI (3.14). As expected, the BEA framework showed the highest capacity of framework Ti species than MFI and MEL frameworks by atom-planting method. This high framework Ti content demonstrated outstanding 1-hexene epoxidation performances (TON: 1827.5). This work paves the way to rationally design Ti-containing zeolites by atom-planting method for epoxidation reactions.