Self-Induced and Progressive Photo-Oxidation of Organophosphonic Acid Grafted Titanium Dioxide

Nick Gys; Bram Pawlak; Kristof Marcoen; Gunter Reekmans; Leticia F Velasco; Rui An; Kenny Wyns; Kitty Baert; Kaimin Zhang; Léon Luntadila Lufungula; Alessandra Piras; Laurens Siemons; Bart Michielsen; Sabine Van Doorslaer; Frank Blockhuys; Tom Hauffman; Peter Adriaensens; Steven Mullens; Vera Meynen

doi:10.1002/cplu.202200441

Self-Induced and Progressive Photo-Oxidation of Organophosphonic Acid Grafted Titanium Dioxide

Chempluschem. 2023 Mar;88(3):e202200441. doi: 10.1002/cplu.202200441.

Authors

Nick Gys^{1

2

3

4}, Bram Pawlak⁵, Kristof Marcoen⁶, Gunter Reekmans⁵, Leticia F Velasco⁷, Rui An², Kenny Wyns¹, Kitty Baert⁶, Kaimin Zhang², Léon Luntadila Lufungula⁸, Alessandra Piras^{9

10}, Laurens Siemons^{8

11}, Bart Michielsen¹, Sabine Van Doorslaer¹², Frank Blockhuys⁸, Tom Hauffman⁶, Peter Adriaensens⁵, Steven Mullens¹, Vera Meynen^{1

2}

Affiliations

¹ Sustainable Materials, Flemish Institute for Technological Research (VITO NV), Boeretang 200, 2400, Mol, Belgium.
² Laboratory of Adsorption and Catalysis (LADCA), Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium.
³ Present address: Centre for Membrane Separations, Adsorption, Catalysis and Spectroscopy (cMACS), KU Leuven, Celestijnenlaan 200F, 3001, Leuven, Belgium.
⁴ Research Group Electrochemical and Surface Engineering (SURF), Vrije Universiteit Brussel, Pleinlaan, Leuven, 2, 1050, Brussels, Belgium.
⁵ Analytical and Circular Chemistry (ACC), Institute for Materials Research (IMO), Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.
⁶ Research Group Electrochemical and Surface Engineering (SURF), Department Materials and Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
⁷ Department of Chemistry, Royal Military Academy, Renaissancelaan 30, 1000, Brussels, Belgium.
⁸ Structural Chemistry Group, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium.
⁹ Laboratory of Applied Materials Chemistry, Unit of Nanomaterials Chemistry, Department of Chemistry, Namur University, Rue de Bruxelles 61, 5000, Namur, Belgium.
¹⁰ Design and Synthesis of Inorganic Nanomaterials (DESINe), Institute for Materials Research (IMO-IMOMEC), Hasselt University, Agoralaan 1, 3590, Diepenbeek, Belgium.
¹¹ Present address: Institute for Applied Chromatography (IAC), SGS Belgium NV, Polderdijkweg 16, 2030, Antwerp, Belgium.
¹² Laboratory of Biophysics and BioMedical Physics (BIMEF), Department of Chemistry, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium.

PMID: 36802130
DOI: 10.1002/cplu.202200441

Abstract

While synthesis-properties-performance correlations are being studied for organophosphonic acid grafted TiO₂ , their stability and the impact of the exposure conditions on possible changes in the interfacial surface chemistry remain unexplored. Here, the impact of different ageing conditions on the evolution of the surface properties of propyl- and 3-aminopropylphosphonic acid grafted mesoporous TiO₂ over a period of 2 years is reported, using solid-state ³¹ P and ¹³ C NMR, ToF-SIMS and EPR as main techniques. In humid conditions under ambient light exposure, PA grafted TiO₂ surfaces initiate and facilitate photo-induced oxidative reactions, resulting in the formation of phosphate species and degradation of the grafted organic group with a loss of carbon content ranging from 40 to 60 wt %. By revealing its mechanism, solutions were provided to prevent degradation. This work provides valuable insights for the broad community in choosing optimal exposure/storage conditions that extend the lifetime and improve the materials' performance, positively impacting sustainability.

Keywords: ageing; organophosphonic acids; photo-oxidation; surface chemistry; titanium dioxide.

Abstract

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