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Quantitative Determination and Comparison of the Surface Binding of Phosphonic Acid, Carboxylic Acid, and Catechol Ligands on TiO 2 Nanoparticles
Author(s) -
Zeininger Lukas,
Portilla Luis,
Halik Marcus,
Hirsch Andreas
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201601920
Subject(s) - monolayer , adsorption , catechol , desorption , oxide , carboxylic acid , chemistry , anatase , ligand (biochemistry) , nanoparticle , titanium oxide , inorganic chemistry , sorption , chemical engineering , materials science , organic chemistry , nanotechnology , catalysis , biochemistry , receptor , photocatalysis , engineering
The adsorption, desorption, co‐adsorption, and exchange behavior of phosphonic acid, carboxylic acid, and catechol derivatives on the surface of titanium oxide (anatase) nanoparticles are investigated. Thermogravimetric analysis provides a facile and fast‐track quantitative determination of the wet‐chemical monolayer adsorption constants and grafting densities of ten adsorbates, all under neutral pH conditions. This characterization protocol allows straightforward quantification of the relevant thermodynamic data of ligand adsorption and a comparison of ligand adsorption strengths. The reported procedure is proposed as a universal tool and it should be applicable to many other colloidal metal oxide materials. Moreover, the determined values for the adsorption constants and the monolayer grafting densities provide a toolbox for the assessment of the adsorbates’ behavior in desorption, exchange, and co‐adsorption equilibria. This versatile evaluation procedure will help to identify optimal monolayer–surface combinations and to evaluate critical parameters, such as monolayer robustness, ligand exchange rates, or targeted mixed assembly of functionalities.