3D Structure of Nanomaterials under Realistic Conditions

Project Information

REALNANO

Grant agreement ID: 815128

DOI

10.3030/815128

Project closed

EC signature date 17 December 2018

Start date 1 May 2019

End date 31 October 2024

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 000 000,00

EU contribution

€ 2 000 000,00

Coordinated by

UNIVERSITEIT ANTWERPEN
Belgium

Periodic Reporting for period 4 - REALNANO (3D Structure of Nanomaterials under Realistic Conditions)

Reporting period: 2023-11-01 to 2024-10-31

Summary of the context and overall objectives of the project

The properties of nanomaterials are essentially determined by their 3D structure. Electron tomography enables one to measure the morphology and composition of nanostructures in 3D, even at atomic resolution. At the start of REALNANO, all these measurements were performed at room temperature and in ultra-high vacuum, which are conditions that are completely irrelevant for the use of nanoparticles in real applications! Moreover, nanoparticles often have ligands at their surface, which form the interface to the environment. These ligands are mostly neglected in imaging, although they strongly influence the growth, thermal stability and drive self-assembly.

REALNANO therefore developed innovative and quantitative 3D characterisation tools, compatible with the fast changes of nanomaterials that occur in a realistic thermal and gaseous environment. These tools were applied to investigate the stability of nanoparticles with applications in the field of plasmonics and catalysis. As such, REALNANO provided important tools that can be used by the community during the further incorporation of nanomaterials in fields such as green energy, drug delivery, sensing, data storage or hyperthermic cancer treatment. To visualise surface ligands, we developed high-quality graphene liquid pockets. In this manner we created the possibility to understand the role of these ligands during growth of nanoparticles and their self assembly.

REALNANO enabled a completely new research line in the field of 3D imaging of nanomaterials under relevant conditions, leading to optimised stability of predefined nanomaterials. This of importance at a fundamental level and is a prerequisite for the incorporation of nanomaterials in our future technology.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

To combine the principles of in situ transmission electron microscopy (TEM) with 3D characterisation, we developed fast high angle annular dark field scanning TEM (HAADF STEM) electron tomography (ET). We reduced the acquisition time for ET from 1 hour to less than 5 minutes [1-3]. In this manner, we were able to investigate morphological transformations of Au and AuPd octapods at high temperatures [4]. Next, we measured 3D changes in composition for AuAg nanoparticles and could reveal the importance of grain boundaries, present in pentatwinned nanorods [5,6]. We furthermore exploited the use of secondary electrons to obtain a fast 3D characterisation [7,8].

Since gas cell holders do not enable conventional ET, we exploited a methodology based on atom counting [9]. The counting results are used to build a 3D starting model for molecular dynamics simulations. Such simulations may easily result in a closest local minimum in the potential energy landscape where the reconstructed structure deviates from the experiments. We proposed an iterative local minima search algorithm and applied this methodology to investigate the behaviour of CeO2 supported Au nanoparticles at high temperature [10,11]. We furthermore used in situ TEM and tomography to investigate Ni nanoparticles on CeO2 supports during CO2 hydrogenation [12]. Also strong metal-support interaction between Ni nanoparticles and TiO2 during CO2 hydrogenation was studied at the atomic scale under operando conditions [13].

To characterise surface ligands in realistic environments, we developed a novel protocol to prepare graphene TEM supports. Since drying of the ligands during sample preparation was found to be a limitation, we extended the graphene transfer methodology towards the creation of graphene pockets containing a colloidal solution. This approach allowed us to visualise the anisotropy and dynamics of ligand distribution at the Au nanorod surface. We additionally measured the chemical composition of the ligand shell. This work opened a direct visualisation of ligand distribution around nanoparticles, which contributes to explaining the influence of additives on the monodispersity of Au nanorods. This work was published in Nature Chemistry [14].

References:

[1] Vanrompay H, Skorikov A, Bladt E, Béché A, Freitag B, Verbeeck J, Bals S, Ultramicroscopy 221, 113191 (2021).
[2] Albrecht W, Bals S, The Journal of Physical Chemistry C 124, 27276 (2020).
[3] Esteban DA, Vanrompay H, Skorikov A, Béché A, Verbeeck J, Freitag B, Bals S, Microscopy And Microanalysis 27, 2116 (2021).
[4] Albrecht W, Bladt E, Vanrompay H, Smith JD, Skrabalak SE, Bals S, Acs Nano 13, 6522 (2019).
[5] Skorikov A, Albrecht W, Bladt E, Xie X, van der Hoeven JES, van Blaaderen A, Van Aert S, Bals S, Acs Nano 13, 13421 (2019).
[6] Mychinko M, Skorikov A, Albrecht W, Sánchez‐Iglesias A, Zhuo X, Kumar V, Liz‐Marzán LM, Bals S, Small , 2102348 (2021).
[7] Vlasov E, Skorikov A, Sánchez-Iglesias A, Liz-Marzán LM, Verbeeck J, Bals S, ACS Materials Letters 5, 1916 (2023).
[8] Vlasov E, Heyvaert W, Ni B, Van Gordon K, Girod R, Verbeeck J, Liz-Marzán LM, Bals S, ACS Nano 18, 12010 (2024).
[9] Van Aert S, de Backer A, Martinez GT, Goris B, Bals S, Van Tendeloo G, Rosenauer A, Physical Review B 87, 064107 (2013).
[10] Arslan Irmak E, Liu P, Bals S, Van Aert S, Small Methods , 2101150 (2021).
[11] Liu P, Arslan Irmak E, De Backer A, De wael A, Lobato I, Béché A, Van Aert S, Bals S, Nanoscale 13 (2021).
[11] Jenkinson K, Spadaro MC, Golovanova V, Andreu T, Morante JR, Arbiol J, Bals S, Advanced Materials 35, 2306447 (2023).
[12] Monai M, Jenkinson K, Melcherts AEM, Louwen JN, Irmak EA, Van Aert S, Altantzis T, Vogt C, van der Stam W, Duchon T, Smid B, Groeneveld E, Berben P, Bals S, Weckhuysen BM, Science 380, 644 (2023).
[13] Pedrazo-Tardajos A, Claes N, Wang D, Sánchez-Iglesias A, Nandi P, Jenkinson K, De Meyer R, Liz-Marzán LM, Bals S, Nature Chemistry 16, 1278 (2024).

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

In this program, 3D characterisation of nanomaterials has been taken to the next level by tracking 3D changes of the structure and composition of nanoparticles and their surface ligands in a realistic environment. Such experiments are very challenging and much more demanding than a simple combination of electron tomography and in situ TEM.

As a result of the project, fast scanning techniques have been combined with advanced 3D reconstruction algorithms and 3D modelling approaches. In this manner, we have been able to track 3D changes of the structure and composition of nanomaterials under different thermal environments. It is of great importance to note that our innovative methodology also enables the characterisation of nanomaterials that are very sensitive to the electron beam and for which fast measurements are the only possibility to reveal their real 3D structure. We also performed experiments under gaseous environment, which eg allowed us to track under-coordinated atoms in catalytic nanoparticles. These experiments enabled a better understanding of the 3D structure-property connection and will therefore lead to optimised design of nanocatalysts. To visualise surface ligands in 3D, we realised that imaging in a liquid environment is crucial and dedicated graphene liquid pockets for TEM were developed.

The outcome of this program has resulted in the necessary characterisation tools to enable the necessary understanding to improve the properties and stability of nanomaterials at work and may even trigger the synthesis of novel nanostructures.

3D visualization of a Au/Pd octopod before (25 °C) and after heating at different temperatures

Artistic visualisation of a graphene liquid pocket with a Au nano rod surrounded by surface ligands