Optimizing Reflux Synthesis Method of Mo-V-Te-Nb mixed oxide Catalysts for Light Alkane Selective Oxidation

Publication date: Available online 6 November 2019Source: Catalysis TodayAuthor(s): Amada Massó Ramírez, Francisco Ivars-Barceló, JoséM. López NietoAbstractThe investigation here presented studies the effect of the synthesis temperature (from 80 to 110 °C) and the time (from 1 to 4 days) employed to precipitate catalyst precursors by reflux method, on the physic-chemical and the catalytic properties of the resulting Mo-V-Te-Nb mixed oxide catalysts for both propane partial oxidation into acrylic acid and ethane oxidative dehydrogenation (ODH) to ethylene. The insight obtained has allowed an important optimization of the not commonly used reflux method to prepare Mo-V-Te-Nb oxide materials with competitive catalytic performance. The yields achieved overcome those from optimized catalysts prepared by conventional hydrothermal method, and approach those reached with catalysts prepared using the “slurry method”. The optimum rise for the synthesis temperature is found as a key factor for the reflux method. It allows access to an increased vanadium content into the reflux precipitate, which favors the formation of a pseudo-amorphous Mo-V-Te-Nb oxometallate. This precipitate behaves as a precursor for the crystallization, during the solid-state activation step at high-temperature (600 °C/N2), of the structure type (TeO)2M20O56 (M = Mo, V, Nb), key for the selective conversion of propane. On the other hand, for the optimum temperature of synthesis, i.e. 110 °C, ...
Source: Catalysis Today - Category: Chemistry Source Type: research