Experimental and Computational Analysis of the Formation of Surface Oxygen Functional Groups during Iron Catalyzed Char Gasification with CO₂

ABSTRACT

An experimental and computational study was carried out to evaluate the role of iron in coal gasification with CO₂. Scanning electron microscopy, energy dispersive X-rays, Mössbauer, X-ray fluorescence, thermogravimetric analysis, and electronic structure methods were used. It was found that even though reaction rates for the catalyzed system are higher, apparent activation energies are not statistically different from the ones obtained for the non-catalyzed reaction. This behavior may be due to an increase in the concentration of surface oxygen complexes when iron is present. Several reaction pathways were proposed by molecular modeling using density functional theory. The presence of iron favors the formation of surface oxygen complexes from a thermodynamic point of view, which agrees with experimental results. It is suggested that iron would increase the concentration of active sites and, as a consequence, there is a rise in the reaction rate with CO₂ in coal gasification with no significant changes in activation energies.

KEYWORDS:

• Computational chemistry
• Iron catalyzed char gasification
• Molecular modeling

Acknowledgments

The authors wish to thank Universidad de Antioquia for the program “Sostenibilidad.” C.J-O also thanks the Colombian National Science Foundation (Colciencias) for the PhD scholarship.

unding

The authors gratefully acknowledge Colciencias and Universidad de Antioquia for financing the research project (1115-452-21242).

Additional information

Funding

The authors gratefully acknowledge Colciencias and Universidad de Antioquia for financing the research project (1115-452-21242).