Infrared Spectroscopic Analysis of the Adsorption of Pyridine Carboxylic Acids on Colloidal Ceria
Autor: | Ashley E. Wayman, Dean J. Campbell, John C. Parker, Wayne B. Bosma, Nicole M. Smiddy, Jamie L Marsh, Edward E. Remsen |
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Rok vydání: | 2017 |
Předmět: |
Inorganic chemistry
chemistry.chemical_element Infrared spectroscopy Protonation 02 engineering and technology Surfaces and Interfaces Picolinic acid 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Isonicotinic acid 01 natural sciences 0104 chemical sciences chemistry.chemical_compound Cerium Adsorption chemistry Pyridine Electrochemistry General Materials Science Carboxylate 0210 nano-technology Spectroscopy |
Zdroj: | Langmuir : the ACS journal of surfaces and colloids. 33(46) |
ISSN: | 1520-5827 |
Popis: | Surface adsorption of a homologous series of pyridine carboxylic acids on a hydrated colloidal cerium dioxide (ceria) film is characterized using the combination of experimental and computationally determined infrared (IR) spectra. Experimental analyses employ attenuated total reflectance (ATR) IR spectroscopy of deposited colloidal ceria thin films equilibrated with three pyridine carboxylic acids at pH 3.0, 5.5, and 8.5. The corresponding computational IR spectra for the energy-minimized intermediate and base forms of the pyridine carboxylic acids use density functional theory calculations at the B3LYP/6-311++G** level of theory. Solvent effects are modeled using both the COSMO implicit solvation model and the inclusion of explicit water molecules. Experimental IR spectra show that the adsorptive interactions between the pyridine carboxylic acids and ceria surface are due to the outer-sphere coordination of cerium ions in the films. Vibrational assignments based on combined experimental and computational results indicate that both pyridyl ring nitrogen and carboxylate functional groups account for the interaction of pyridine carboxylic acids at ceria surfaces. Experimentally determined Langmuir constants point to the intermediate form of picolinic acid (pyridine-2-carboxylic acid) as having the strongest adsorption to ceria compared to the other pyridine carboxylic acids investigated. The enhanced adsorption of picolinic acid is attributed to the adjacency of the protonated pyridyl nitrogen and the carboxylate group relative to nicotinic acid (pyridine-3-carboxylic acid) and isonicotinic acid (pyridine-4-carboxylic acid). |
Databáze: | OpenAIRE |
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