CHARACTERIZATION OF CARBON DEPOSITED FROM CARBON-DIOXIDE ON OXYGEN-DEFICIENT MAGNETITES

Oxygen-deficient magnetite (ODM) powder has been reacted with CO2 at 3 00-degrees-C; black particles of carbon separated from the ODM were st udied by Raman, energy-dispersive X-ray (EDX) and wave-dispersive X-ra y (WDX) spectroscopies. The carbon was a mixture of graphite and amorp hous carbon in at least two levels of crystallization. Temperature-pro grammed desorption-mass spectrometry (TPD-MS) showed that a large port ion of the carbon deposited on the ODM was released as CO and CO2 gas in a flow of Ar at ca. 520-degrees-C, indicating that the carbon parti cles formed on the ODM are reactive. X-Ray photoelectron spectra of th e carbon-deposited ODM showed no indication of carbide (Fe3C) or alpha -Fe phase formation.