کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
42319 | 45920 | 2009 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: An iron molybdate catalyst for methanol to formaldehyde conversion prepared by a hydrothermal method and its characterization An iron molybdate catalyst for methanol to formaldehyde conversion prepared by a hydrothermal method and its characterization](/preview/png/42319.png)
A one-step, low-temperature hydrothermal method has been successfully employed to prepare iron molybdate catalysts with Mo:Fe ratios ranging from 1.5:1 to 3.0:1. The resulting materials were characterized using a number of techniques including: XRD, Raman, N2 adsorption, SEM/EDX, DTA, EDXRD and combined XRD/XAS. The catalytic oxidative dehydrogenation of methanol to formaldehyde has been used as a test reaction. For Mo:Fe ∼ 1.5, phase-pure Fe2(MoO4)3 resulted from syntheses performed at temperatures as low as 100 °C in under 4 h. For samples with a Mo:Fe ∼ 3 detailed analysis of XRD, Raman and EXAFS data revealed the formation of a high surface area possessing, mixed phase material consisting of a poorly crystalline Mo5O14 and an amorphous Fe2(MoO4)3 type precursor. Both phases proved to be thermally unstable above a calcination temperature of 300 °C, going on to form high surface area mixed Fe2(MoO4)3/MoO3. Continued heating of this mixed oxide material resulted in sintering and to a decrease in the surface area. When both mildly (200 °C) and then more severely calcined (300 °C), this mixed phase sample showed a higher selectivity for formaldehyde production than a conventionally prepared (via co-precipitation) iron molybdate catalyst.
A one-step, low-temperature hydrothermal method has been successfully employed to prepare high surface area iron molybdate catalysts with Mo:Fe ratios of 1.5:1–3:1. Syntheses performed with a Mo:Fe ∼ 3 resulted in a mixed crystalline Mo5O14/amorphous FeMo oxide phase, with the chemical formula which was unstable above a calcination temperature of 300 °C, forming mixed Fe2(MoO4)3/MoO3. The Mo:Fe ∼ 3 phase after both mild (200 °C) and more severe calcinations (300 °C), showed a higher selectivity for formaldehyde production than a conventionally prepared (via co-precipitation) iron molybdate catalyst.Figure optionsDownload as PowerPoint slide
Journal: Applied Catalysis A: General - Volume 363, Issues 1–2, 1 July 2009, Pages 143–152