Iron nitride catalysts composition changes

Nitrided iron catalysts are remarkably stable toward oxidation and deposition of elemental carbon in the synthesis at both 7.8 and 21.4 atm. Shultz, Seligman, Lecky, and Anderson (23) described composition changes in nitrided fused, sintered, and precipitated catalysts in the synthesis. In a test (X218) with 1H2 + ICO synthesis gas at 7.8 atm., the catalyst was sampled frequently for analysis. X-ray diffraction patterns showed only the e-nitride or carbonitride phase, except for weak... 

Changes of Composition of Nitrided Iron Catalysts during the Synthesis 373... 

FIGURE 5 Characterization of iron ammonia synthesis catalyst. High-resolution laboratory diffraction indicated a reversible modification of the iron (111) line profile. Under catalytic reaction conditions, a sub-nitride with x = 15-18 is present in addition to the bulk iron matrix. The fitting and assignment of the data were substantiated by observations of the line profile during step changes in the composition of the gas atmosphere. Details and references are given in the text. 

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