Influence of calcination conditions on the phase composition of vanadium-phosphorus oxide catalysts

B. K. Hodnett, B. Delmon

Research output: Contribution to journalArticlepeer-review

Abstract

The influence of calcination time and temperature on the formation of phases related to VPO catalysts with P/V ratios in the range 0.90 to 1.10 has been studied. In the preparation, lactic acid was used for the reduction of V2O5 and the reduced vanadium complex thus formed was reacted with o-H3PO4. The evolution of phases was followed by XRD. For calcinations at 773 K, low P/V ratios favour the formation of βVPO5; high ratios (>1) favour the formation of a reduced phase labelled β* (d = 4.67, 4.07, 3.14 and 2.59 Å). For all P/V ratios studied, this phase was not stable in air at 773 K but transformed slowly into βVPO5. The β*/βVPO5 ratio did not influence the surface area. The β* phase was not observed after calcination above 873 K. For calcination of catalysts with a P/V ratio of 1.10, carried out at 923 K, a reduced phase with principal d spacings at 3.90, 3.13 and 2.99 Å and variously labelled B, β and (VO)2P2O7 in the literature, was observed.

Original languageEnglish
Pages (from-to)203-211
Number of pages9
JournalApplied Catalysis
Volume9
Issue number2
DOIs
Publication statusPublished - 15 Feb 1984
Externally publishedYes

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