### Abstract

The distributions of Al tetrahedral sites are studied as a function of Si : Al ratio (from 11 to 95) in three zeolites: ZSM-5, ferrierite, and mordenite. Al configurations obeying Loewenstein's rule are generated by a Monte Carlo procedure and analyzed in terms of accessibility to specific channels. The distribution of pairs of Al sites accessible to the same channel segregates into distinct nearest-neighbor and ring-bridging types. Such pairs provide favorable binding environments for extraframework MO_{x}M^{2+} cations in the metal-ion-exchanged forms of the zeolites. In all three zeolites, the probability of a given Al site having at least one suitable partner for pairing within 8.5 Å is close to unity for typical Si : Al ratios. The probability at shorter distances is more sensitive to the zeolite structure, reflecting the larger number of highly puckered five-and six-membered rings in ZSM-5. This sensitivity, and its implications for CuO_{x}Cu^{2+} formation in the three Cu-exchanged forms, may explain why Cu-ZSM-5 is the most active of the three for catalytically decomposing NO.

Original language | English (US) |
---|---|

Pages (from-to) | 85-93 |

Number of pages | 9 |

Journal | Catalysis Letters |

Volume | 68 |

Issue number | 1-2 |

State | Published - Aug 2000 |

### Fingerprint

### Keywords

- Al pairs
- Cu oxocations
- Ferrierite
- Monte Carlo sampling
- Mordenite
- NO decomposition
- Zeolites
- ZSM-5

### ASJC Scopus subject areas

- Catalysis
- Physical and Theoretical Chemistry

### Cite this

*Catalysis Letters*,

*68*(1-2), 85-93.

**Statistical analysis of Al distributions and metal ion pairing probabilities in zeolites.** / Goodman, B. R.; Hass, K. C.; Schneider, W. F.; Adams, James.

Research output: Contribution to journal › Article

*Catalysis Letters*, vol. 68, no. 1-2, pp. 85-93.

}

TY - JOUR

T1 - Statistical analysis of Al distributions and metal ion pairing probabilities in zeolites

AU - Goodman, B. R.

AU - Hass, K. C.

AU - Schneider, W. F.

AU - Adams, James

PY - 2000/8

Y1 - 2000/8

N2 - The distributions of Al tetrahedral sites are studied as a function of Si : Al ratio (from 11 to 95) in three zeolites: ZSM-5, ferrierite, and mordenite. Al configurations obeying Loewenstein's rule are generated by a Monte Carlo procedure and analyzed in terms of accessibility to specific channels. The distribution of pairs of Al sites accessible to the same channel segregates into distinct nearest-neighbor and ring-bridging types. Such pairs provide favorable binding environments for extraframework MOxM2+ cations in the metal-ion-exchanged forms of the zeolites. In all three zeolites, the probability of a given Al site having at least one suitable partner for pairing within 8.5 Å is close to unity for typical Si : Al ratios. The probability at shorter distances is more sensitive to the zeolite structure, reflecting the larger number of highly puckered five-and six-membered rings in ZSM-5. This sensitivity, and its implications for CuOxCu2+ formation in the three Cu-exchanged forms, may explain why Cu-ZSM-5 is the most active of the three for catalytically decomposing NO.

AB - The distributions of Al tetrahedral sites are studied as a function of Si : Al ratio (from 11 to 95) in three zeolites: ZSM-5, ferrierite, and mordenite. Al configurations obeying Loewenstein's rule are generated by a Monte Carlo procedure and analyzed in terms of accessibility to specific channels. The distribution of pairs of Al sites accessible to the same channel segregates into distinct nearest-neighbor and ring-bridging types. Such pairs provide favorable binding environments for extraframework MOxM2+ cations in the metal-ion-exchanged forms of the zeolites. In all three zeolites, the probability of a given Al site having at least one suitable partner for pairing within 8.5 Å is close to unity for typical Si : Al ratios. The probability at shorter distances is more sensitive to the zeolite structure, reflecting the larger number of highly puckered five-and six-membered rings in ZSM-5. This sensitivity, and its implications for CuOxCu2+ formation in the three Cu-exchanged forms, may explain why Cu-ZSM-5 is the most active of the three for catalytically decomposing NO.

KW - Al pairs

KW - Cu oxocations

KW - Ferrierite

KW - Monte Carlo sampling

KW - Mordenite

KW - NO decomposition

KW - Zeolites

KW - ZSM-5

UR - http://www.scopus.com/inward/record.url?scp=0034254061&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034254061&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0034254061

VL - 68

SP - 85

EP - 93

JO - Catalysis Letters

JF - Catalysis Letters

SN - 1011-372X

IS - 1-2

ER -