Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis

Molybdenum-vanadium oxide (Mo-V-O) has been constantly reported as an active and selective catalyst for the direct propane transformation to acrylic acid. In this study, crystalline molybdenum-vanadium oxide catalysts have been successfully synthesized by homogeneous precipitation method using urea...

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Main Author:	Woi, Pei Meng
Format:	Thesis
Language:	English English
Published:	2007
Subjects:	Catalysis Vanadium catalysts
Online Access:	http://psasir.upm.edu.my/id/eprint/4999/1/FS_2007_16.pdf
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spelling	my-upm-ir.49992013-05-27T07:19:40Z Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis 2007 Woi, Pei Meng Molybdenum-vanadium oxide (Mo-V-O) has been constantly reported as an active and selective catalyst for the direct propane transformation to acrylic acid. In this study, crystalline molybdenum-vanadium oxide catalysts have been successfully synthesized by homogeneous precipitation method using urea hydrolysis. A new approach was taken whereby the solid obtained were further refluxed in the presence of additives which are adipic acid (AA), maleic acid (MA) and polyvinyl alcohol (PVA). The precursors which upon drying were subjected to various calcination temperatures. The effect of additives and calcination temperatures on the formation and properties of Mo-V-O characteristics were monitored by Thermogravimetric Analysis (TGA), Powder X-ray diffraction (XRD), Photon Cross Correlation Spectroscopy (PCCS), Inductively Couple Plasma-Atomic Emission Spectroscopy (ICP-AES), BET Surface Area Measurements (SBET), Scanning Electron Microscopy (SEM) and Hydrogen-Temperature Programmed Reduction (H2-TPR). It was found that without the presence of additives, the precursor was in a semicrystalline form of ammonium molybdate anorthic phase. However, in the presence of additives, the precursors were highly crystalline with the presence of desirable orthorhombic, monoclinic and tetragonal MoVOx species. Heat treatment that imposed on the materials has successfully transformed the precursor into a more stable phase. The desirable orthorhombic phase was found to be achieved when sample was calcined at 873 K in nitrogen atmosphere. SEM analysis showed a rather randomly distributed particle with defined size and shape. Total surface area, SBET for sample prepared by complexing MoV salts with PVA (MoVPVA873) was found to be the highest, i.e. 20.5 m2 g-1. This property consequently contributed to the highest total amount of oxygen species removed from the oxide, hence an indication of the highly active and selective characteristics borne by the oxide. This is further confirmed by catalytic test of propane oxidation to acrylic acid which done on the sample. The test showed that samples treated with organic species (AA, MA, PVA) give better acrylic acid selectivity and yield. Catalysis Vanadium catalysts 2007 Thesis http://psasir.upm.edu.my/id/eprint/4999/ http://psasir.upm.edu.my/id/eprint/4999/1/FS_2007_16.pdf application/pdf en public masters Universiti Putra Malaysia Catalysis Vanadium catalysts Science English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
topic	Catalysis Vanadium catalysts
spellingShingle	Catalysis Vanadium catalysts Woi, Pei Meng Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis
description	Molybdenum-vanadium oxide (Mo-V-O) has been constantly reported as an active and selective catalyst for the direct propane transformation to acrylic acid. In this study, crystalline molybdenum-vanadium oxide catalysts have been successfully synthesized by homogeneous precipitation method using urea hydrolysis. A new approach was taken whereby the solid obtained were further refluxed in the presence of additives which are adipic acid (AA), maleic acid (MA) and polyvinyl alcohol (PVA). The precursors which upon drying were subjected to various calcination temperatures. The effect of additives and calcination temperatures on the formation and properties of Mo-V-O characteristics were monitored by Thermogravimetric Analysis (TGA), Powder X-ray diffraction (XRD), Photon Cross Correlation Spectroscopy (PCCS), Inductively Couple Plasma-Atomic Emission Spectroscopy (ICP-AES), BET Surface Area Measurements (SBET), Scanning Electron Microscopy (SEM) and Hydrogen-Temperature Programmed Reduction (H2-TPR). It was found that without the presence of additives, the precursor was in a semicrystalline form of ammonium molybdate anorthic phase. However, in the presence of additives, the precursors were highly crystalline with the presence of desirable orthorhombic, monoclinic and tetragonal MoVOx species. Heat treatment that imposed on the materials has successfully transformed the precursor into a more stable phase. The desirable orthorhombic phase was found to be achieved when sample was calcined at 873 K in nitrogen atmosphere. SEM analysis showed a rather randomly distributed particle with defined size and shape. Total surface area, SBET for sample prepared by complexing MoV salts with PVA (MoVPVA873) was found to be the highest, i.e. 20.5 m2 g-1. This property consequently contributed to the highest total amount of oxygen species removed from the oxide, hence an indication of the highly active and selective characteristics borne by the oxide. This is further confirmed by catalytic test of propane oxidation to acrylic acid which done on the sample. The test showed that samples treated with organic species (AA, MA, PVA) give better acrylic acid selectivity and yield.
format	Thesis
qualification_level	Master's degree
author	Woi, Pei Meng
author_facet	Woi, Pei Meng
author_sort	Woi, Pei Meng
title	Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis
title_short	Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis
title_full	Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis
title_fullStr	Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis
title_full_unstemmed	Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis
title_sort	characterization of molybdenum-vanadium oxide catalyst prepared by homogeneous precipitation method using urea hydrolysis
granting_institution	Universiti Putra Malaysia
granting_department	Science
publishDate	2007
url	http://psasir.upm.edu.my/id/eprint/4999/1/FS_2007_16.pdf
_version_	1747810327527948288

Characterization of Molybdenum-Vanadium Oxide Catalyst Prepared By Homogeneous Precipitation Method Using Urea Hydrolysis

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