An outstanding Cr-doped catalyst for selective oxidation of propane to acrylic acid

Abstract

The catalytic performance of active MoVTeNbO x catalysts containing an M1 phase in the partial oxidation of propane to acrylic acid (AA) was greatly improved when an optimal amount of Cr was added. The catalyst containing Cr/Nb (molar ratio = 0.002) showed good selectivity (78.3%) and high AA yield (50.7%). The catalysts were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, H 2 temperature-programmed reduction, O 2 and NH 3 temperature-programmed desorption, and oxidation of 2-propanol. The relationship between the catalyst structure and catalytic properties was investigated. The results indicated that the amounts of Mo 6+ , V 5+ and Te 4+ species on the catalyst surface were adjusted, and oxidation activity of the catalyst increased, as a result of doping with an appropriate amount Cr, which promoted propane activation. The acid strength became weaker, and the number of acid sites on the catalyst surface decreased, which suppressed AA oxidation and improved the selectivity for AA. An active MoVTeNbO x catalyst doped with the optimal amount of Cr gave an acrylic acid yield of 50.7%, exceeding the highest acrylic acid yield reported to date.