Aqueous or solvent based surface modification: The influence of the combination solvent – organic functional group on the surface characteristics of titanium dioxide grafted with organophosphonic acids

Roevens, Annelore; Dijck, Jeroen G. Van; Geldof, Dirk; Blockhuys, Frank; Prelot, Bénédicte; Zając, Jerzy; Meynen, Vera

doi:10.1016/j.apsusc.2017.04.143

Cited by 14 publications

(21 citation statements)

References 39 publications

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“…It is known that the modification conditions (temperature, concentration, solvent), type of PA and support properties (crystal phases and facets) strongly affect the properties of the modified surface. 59,60 Guerrero et al 61 modified P25 with an aqueous solution of phenylphosphonic acid (PhPA) and observed an increase in phosphorus content with increasing temperature. They also described a dissolution-precipitation reaction at the surface (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…In a more elaborate study on Al2O3 49 , an increasing broadening of the 31 P NMR resonance signals was observed upon higher octylphosphonic acid loading, indicating relative changes in the binding modes. More recently, the work of Roevens et al 59,60 provided systematic insight into the role of the modification conditions on the grafting of TiO2 (P25) with propyl-and phenylphosphonic acid in water and toluene.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and computational insights into the aminopropylphosphonic acid modification of mesoporous TiO2 powder: The role of the amine functionality on the surface interaction and coordination

Gys

Siemons

Pawlak

et al. 2021

Applied Surface Science

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Recently, interest has been directed towards the grafting of metal oxides with organophosphonic acids bearing terminal amine groups to extend the functionality and applicability of these materials. Previous reports mainly focus on the application perspective, while a detailed characterization of the surface properties at the molecular level and the correlation with the synthesis conditions are missing. In this work, mesoporous TiO2 powder is grafted with 3-aminopropylphosphonic acid (3APPA) under different concentrations (20, 75, 150 mM) and temperatures (50, 90 °C) and compared with propylphosphonic acid (3PPA) grafting to unambiguously reveal the impact of the amine group on the surface properties. A combination of complementary spectroscopic techniques and Density Functional Theory -Periodic Boundary Conditions (DFT/PBC) calculations are used. At 90 °C and high concentrations, lower modification degrees are obtained for 3APPA compared to Revised manuscript (unmarked) ick ere t vie inked Re erences 2 3PPA, due to amine-induced surface interactions. Both X-ray Photoelectron Spectroscopy (XPS) and Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy reveal that both NH2 and NH3 + groups are present, with also contributions of NH2 groups involved in hydrogen bonding interactions. A similar ratio of NH2/NH3 + (65:35) is obtained irrespective of the modification conditions, suggesting similar relative contributions of different surface conformations. Calculated adsorption energies from DFT calculations on 3APPA adsorption on anatase (101) in relation to the water coverage reveals a coexistence of various structures with the amine group involved in intra-adsorbate, inter-adsorbate and adsorbate-surface interactions. Further validation is obtained from the strong overlap of different 31 P environments represented by the broad band (35-12 ppm) in experimental 31 P Nuclear Magnetic Resonance (NMR) spectra and calculated 31 P chemical shifts of all modelled monodentate and bidentate structures. Structures related to the tridentate binding mode are not formed due to geometric restrictions of the anatase (101) facet applied as model support in the calculations. Nevertheless, they could be present in the experimental samples as they are composed of anatase (representing multiple crystal facets) and an amorphous titania fraction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental and computational insights into the aminopropylphosphonic acid modification of mesoporous TiO2 powder: The role of the amine functionality on the surface interaction and coordination

Gys

Siemons

Pawlak

et al. 2021

Applied Surface Science

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“…A characteristic P–OH stretch is observed for 6 at 989 cm –1 that disappears after attachment. Instead, a new peak at 1050 cm –1 emerges in agreement with the formation of a Ti–O–P bond, indicating covalent binding to the surface …”

Section: Resultsmentioning

confidence: 85%

“…Instead, a new peak at 1050 cm −1 emerges in agreement with the formation of a Ti−O−P bond, indicating covalent binding to the surface. 26 Effects of Attachment Moiety on Catalysis. To compare the new P-attached catalyst to the N-attached version, we used HER in aqueous solution as the benchmark reaction.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Investigation of Immobilization Effects on Ni(P₂N₂)₂ Electrocatalysts

2020

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A new synthetic route to complexes of the type Ni(P2N2)2 2+ with highly functionalized phosphine substituents and the investigation of immobilization effects on these catalysts is reported. Ni(P2N2)2 2+ complexes have been extensively studied as homogeneous and surface-attached molecular electrocatalysts for the hydrogen evolution reaction (HER). A synthesis based on postsynthetic modification of PArBr 2NPh 2 was developed and is described here. Phosphonate-modified ligands and their corresponding nickel complexes were isolated and characterized. Subsequent deprotection of the phosphonic ester derivatives provided the first Ni(P2N2)2 2+ catalyst that can be covalently attached via pendent phosphonate groups to an electrode without involvement of the important pendent amine groups. Mesoporous TiO2 electrodes were surface modified by attachment of the new phosphonate functionalized Ni(P2N2)2 2+ complexes, and these provided electrocatalytic materials that proved to be competent and stable for sustained HER in aqueous solution at mild pH and low overpotential. We directly compared the new ligand to a previously reported complex that utilized the amine moiety for surface attachment. Using HER as the benchmark reaction, the P-attached catalyst showed a marginally (9–14%) higher turnover number than its N-attached counterpart.

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“…organosilanes [9][10][11][12][13][14], organophosphonic acids or their derivatives [15][16][17][18][19][20][21] and others [6] have all shown their ability to form functional organic (mono)layers onto the oxide surface. While these methods have their specific advantages, all bonds occur through heteroatoms (e.g.…”

Section: Introductionmentioning

confidence: 99%

Synthesis – properties correlation and the unexpected role of the titania support on the Grignard surface modification

Dijck

Mampuys

Ching

et al. 2020

Applied Surface Science

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Aqueous or solvent based surface modification: The influence of the combination solvent – organic functional group on the surface characteristics of titanium dioxide grafted with organophosphonic acids

Cited by 14 publications

References 39 publications

Experimental and computational insights into the aminopropylphosphonic acid modification of mesoporous TiO2 powder: The role of the amine functionality on the surface interaction and coordination

Experimental and computational insights into the aminopropylphosphonic acid modification of mesoporous TiO2 powder: The role of the amine functionality on the surface interaction and coordination

Investigation of Immobilization Effects on Ni(P₂N₂)₂ Electrocatalysts

Synthesis – properties correlation and the unexpected role of the titania support on the Grignard surface modification

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Aqueous or solvent based surface modification: The influence of the combination solvent – organic functional group on the surface characteristics of titanium dioxide grafted with organophosphonic acids

Cited by 14 publications

References 39 publications

Experimental and computational insights into the aminopropylphosphonic acid modification of mesoporous TiO2 powder: The role of the amine functionality on the surface interaction and coordination

Experimental and computational insights into the aminopropylphosphonic acid modification of mesoporous TiO2 powder: The role of the amine functionality on the surface interaction and coordination

Investigation of Immobilization Effects on Ni(P2N2)2 Electrocatalysts

Synthesis – properties correlation and the unexpected role of the titania support on the Grignard surface modification

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Investigation of Immobilization Effects on Ni(P₂N₂)₂ Electrocatalysts