A density functional study of pentacoordinated phosphorus species in ZSM-5 zeolite

Incorporation of P into ZSM-5 framework greatly improves the catalytic properties of the molecular sieve. To understand the feasibility of existence of pentacoordinated phosphorus species in ZSM-5, we designed a model reaction and studied it using density functional theory at B3LYP/6-31G* level to evaluate its thermodynamics. The result demonstrates that the formation of pentacoordinated phosphorus species is thermodynamically favorable at high temperatures by hydrothermal treatment of the ZSM-5 modified with phosphorus acid. (c) 2010 Elsevier B.V. All rights reserved.