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Elasticity of Cross-Linked Titania Nanocrystal Assemblies Probed by AFM-Bulge Tests. NANOMATERIALS 2019; 9:nano9091230. [PMID: 31470667 PMCID: PMC6780250 DOI: 10.3390/nano9091230] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 08/22/2019] [Accepted: 08/25/2019] [Indexed: 01/22/2023]
Abstract
In order to enable advanced technological applications of nanocrystal composites, e.g., as functional coatings and layers in flexible optics and electronics, it is necessary to understand and control their mechanical properties. The objective of this study was to show how the elasticity of such composites depends on the nanocrystals’ dimensionality. To this end, thin films of titania nanodots (TNDs; diameter: ~3–7 nm), nanorods (TNRs; diameter: ~3.4 nm; length: ~29 nm), and nanoplates (TNPs; thickness: ~6 nm; edge length: ~34 nm) were assembled via layer-by-layer spin-coating. 1,12-dodecanedioic acid (12DAC) was added to cross-link the nanocrystals and to enable regular film deposition. The optical attenuation coefficients of the films were determined by ultraviolet/visible (UV/vis) absorbance measurements, revealing much lower values than those known for titania films prepared via chemical vapor deposition (CVD). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed a homogeneous coverage of the substrates on the µm-scale but a highly disordered arrangement of nanocrystals on the nm-scale. X-ray photoelectron spectroscopy (XPS) analyses confirmed the presence of the 12DAC cross-linker after film fabrication. After transferring the films onto silicon substrates featuring circular apertures (diameter: 32–111 µm), freestanding membranes (thickness: 20–42 nm) were obtained and subjected to atomic force microscopy bulge tests (AFM-bulge tests). These measurements revealed increasing elastic moduli with increasing dimensionality of the nanocrystals, i.e., 2.57 ± 0.18 GPa for the TND films, 5.22 ± 0.39 GPa for the TNR films, and 7.21 ± 1.04 GPa for the TNP films.
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Sordello F, Odorici E, Hu K, Minero C, Cerruti M, Calza P. Shape controllers enhance the efficiency of graphene-TiO2 hybrids in pollutant abatement. NANOSCALE 2016; 8:3407-3415. [PMID: 26791107 DOI: 10.1039/c5nr07257c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The addition of graphene nanoplatelets (GNP) to TiO2 nanoparticles (NPs) has been recently considered as a method to improve the photocatalytic efficiency of TiO2 by favoring charge carrier separation. Here, we show that it is possible to improve the efficiency of GNP-TiO2 composites by controlling the shape, stability, and facets of TiO2 NPs grown on GNP functionalized with either COOH or NH2 groups, while adding ethylendiamine (EDA) and oleic acid (OA) during a hydrothermal synthesis. We studied the photocatalytic activity of all synthesized materials under UV-A light using phenol as a target molecule. GNP-TiO2 composites synthesized on COOH-functionalized GNP, exposing {101} facets, were more efficient at abating phenol than those synthesized on NH2-functionalized GNP, exposing {101} and {100} facets. However, neither of these composites was stable under irradiation. The addition of both OA and EDA stabilized the materials under irradiation; however, only the composite prepared on COOH-functionalized GNP in the presence of EDA showed a significant increase in phenol degradation rate, leading to results that were better than those obtained with TiO2 alone. This result can be attributed to Ti-OH complexation by EDA, which protects GNP from oxidation. The orientation of the most reducing {101} facets toward GNP and the most oxidizing {100} facets toward the solution induces faster phenol degradation owing to a better separation of the charge carriers.
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Affiliation(s)
- F Sordello
- Department of Chemistry, University of Turin, Via Giuria, 5, I-10125 Turin, Italy. and Materials Engineering, McGill University, 3610 University St., Montreal, QC H3A 0C5, Canada
| | - E Odorici
- Department of Chemistry, University of Turin, Via Giuria, 5, I-10125 Turin, Italy.
| | - K Hu
- Materials Engineering, McGill University, 3610 University St., Montreal, QC H3A 0C5, Canada
| | - C Minero
- Department of Chemistry, University of Turin, Via Giuria, 5, I-10125 Turin, Italy.
| | - M Cerruti
- Materials Engineering, McGill University, 3610 University St., Montreal, QC H3A 0C5, Canada
| | - P Calza
- Department of Chemistry, University of Turin, Via Giuria, 5, I-10125 Turin, Italy.
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Sarro M, Cerruti M, Calza P, Anfossi L. Carboxylated graphene–TiO2 hybrids as multifunctional materials: from photocatalysis to peroxidase alternatives. RSC Adv 2016. [DOI: 10.1039/c6ra07808g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hybrid materials with multifunctional properties were synthetized by coupling graphene nanoplatelets modified with carboxylic groups to TiO2 and applied as photocatalyst and as tracers of the presence of a model antigen in immunochemical assays.
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Affiliation(s)
- M. Sarro
- Università di Torino
- Dipartimento di Chimica
- 10125 Torino
- Italy
| | - M. Cerruti
- McGill University
- Materials Engineering
- Montreal
- Canada
| | - P. Calza
- Università di Torino
- Dipartimento di Chimica
- 10125 Torino
- Italy
| | - L. Anfossi
- Università di Torino
- Dipartimento di Chimica
- 10125 Torino
- Italy
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Hu L, Wang J, Zhang J, Zhang Q, Liu Z. An N-doped anatase/rutile TiO2hybrid from low-temperature direct nitridization: enhanced photoactivity under UV-/visible-light. RSC Adv 2014. [DOI: 10.1039/c3ra44421j] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Design of graphene and silica co-doped titania composites with ordered mesostructure and their simulated sunlight photocatalytic performance towards atrazine degradation. Colloids Surf A Physicochem Eng Asp 2013. [DOI: 10.1016/j.colsurfa.2013.01.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yang G, Jiang Z, Shi H, Xiao T, Yan Z. Preparation of highly visible-light active N-doped TiO2 photocatalyst. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm00376j] [Citation(s) in RCA: 571] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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