The Hydrothermal Synthesis and Characterization of New Organically Templated Layered Vanadium Oxides by Methylamine
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173 Mat. Res. Soc. Symp. Proc. Vol. 497 ©1998 Materials Research Society
EXPERIMENTAL Three layered vanadium oxides were hydrothermnally synthesized by dissolving V 2 0 5 powder from Johnson & Matthey in methylamine aqueous solution from Fisher Scientific in a 1:2 molar ratio. After adjusting the pH with an acid, the final solution was transferred to a 125-mi Teflon lined autoclave (Parr bomb), sealed, and reacted hydrothermally for 4 or 5 days at 200'C. When HAc was used to adjust the pH to 4, a block of dark green clay (CH3 NH 3)0.75V 4 0 10"0.67H 20 was obtained; the final pH after reaction was 4.5. When HAc was used to adjust initial pH to 7, large dark brown plate-like crystals (CH 3NH 3)V 30 7 were obtained; the final pH was 7 after reaction. When HNO 3 was used to adjust the pH value to 3.5, black shining crystals (CH 3NH 2)2 V80 1 7 were obtained; the final pH after reaction was 9. All the compounds were overnight dried in 45'C oven before use. X-ray powder diffraction data was recorded using CuKcx radiation on a Scintag XDS 2000 0-0 diffractometer. The data was collected in a continuous scan at 0.1 '/min over the range 60
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