Synthesis and characterization of nanocrystalline Mo-V-W-Fe-O mixed oxide catalyst and its performance in selective methanol oxidation

Abstract

A mixed oxide catalyst containing Mo, V, W and Fe with the composition of 63, 23, 09 and 06 wt% respectively for the selective oxidation of the methanol to formaldehyde is in reported in this paper for the first time. The characterization of the catalyst was done using BET surface analysis, X-ray diffraction (XRD), Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX). The mixed oxide after calcination at 673 K in N<inf>2</inf> which was subjected for the thermal activation in N <inf>2</inf>flow at 813 K was used for the methanol selective oxidation. The thermal treatment shows enhanced catalytic performance. Thermal activation of the nanocrystalline Mo<inf>0.63</inf>V<inf>23</inf>W<inf>0.09</inf>Fe <inf>0</inf>.<inf>06</inf>O <inf>x</inf> precursor oxide in nitrogen atmospheres induces partial crystallization of a Mo<inf>5</inf>O<inf>14</inf>-type oxide only in a narrow temperature range up to 813 K. XRD showed that the thermally activated mixed oxide consists of a mixture of a majority of crystalline Mo <inf>5</inf>O<inf>14</inf>-type oxide and of small amounts of crystalline MoO<inf>3</inf>-type and MoO<inf>2</inf>-type oxides. The structural analysis suggests that the improvement of the catalytic performance of the MoVWFe oxide catalyst in the selective oxidation of methanol is related to the formation of the catalytic active site such as Mo<inf>5</inf>O<inf>14</inf>-type mixed oxide. © 2007 Springer Science+Business Media, LLC.