Characterization and evaluation of Mo [sbnd]V [sbnd]Te [sbnd]Nb mixed metal oxide catalysts fabricated via hydrothermal process with ultrasonic pretreatment for propane partial oxidation

Abstract

Mo 1.00V x Te 0.20Nb 0.16O n ( x = 0.35 – 0.50 ) mixed-metal oxide catalysts were synthesized through ultrasonic and hydrothermal treatments. Both TeO 2 and H 6TeO 6 were used as tellurium sources. The enhanced dispersion of TeO 2 by ultrasonic treatment is crucial for obtaining an active and selective Mo V Te Nb O catalyst for acrylic acid (AA) formation from propane oxidation. The TeO 2-derived Mo 1.00V x Te 0.20Nb 0.16O n ( x = 0.35 – 0.41 ) are superior to their H 6TeO 6-derived counterparts; propane conversion and AA selectivity over the Mo 1.00V 0.41Te 0.20Nb 0.16O n is 55% and 60 mol% at 380 °C, respectively, giving an AA formation rate of 22.3 μmol g −1 min −1. Based on the physicochemical properties of the catalysts, we propose that the ultrasonic treatment can give rise to (i) enhanced presence of the orthorhombic Te 2 M 20 O 57 ( M = Mo , V, Nb) and hexagonal Te 0.33 MO 3.33 ( M = Mo , V, Nb) phases, (ii) surface enrichment of Te, (iii) enhanced reactivity of lattice oxygen, (iv) an increase in Mo O Te and V O Te entities, and (v) better isolation of active sites.