Surface Acidity of H-Birnessite: Infrared Spectroscopic Study of Formic Acid Decomposition |
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| Authors: | E. Eren H. Gumus B. Eren A. Sarihan |
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| Affiliation: | 1. Bilecik University, Faculty of Arts and Science, Department of Chemistry , Bilecik Turkey erdal.eren@bilecik.edu.tr;3. Bilecik University, Faculty of Arts and Science, Department of Chemistry , Bilecik Turkey |
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| Abstract: | This paper presents the adsorption and thermal decomposition mechanism of formic acid on an H-birnessite sample. Changes in the surface and structure were characterized using infrared spectroscopy, N2 gas adsorption–desorption, and thermal analysis techniques. The acid sites of H-birnessite were investigated by infrared and thermal analysis using pyridine as a molecular probe. Decomposition of formic acid started on H-birnessite at 120°C and was complete at 400°C. Infrared spectra revealed that the molecularly adsorbed formic acid species were transformed to a formate species, and the formate species were transformed to CO. The most stable adsorption structure for formic acid was found as a molecular monodentate configuration. |
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| Keywords: | birnessite manganese oxide Mn2O3 Mn3O4 MnO2 surface acidity |
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