Equilibrium phase diagram showing stability conditions for water ice and vapour in a closed system (modified after Andreas, 2007 and Weikusat et al., 2011).

The equilibrium temperature for a chamber pressure of 1×10−6 hPa is approximately -112°C. The SEM chamber pressure and temperature for the current study’s experiments are shown with a star.</p

Optimised and corrected nanoindentation data on ice.

(XLSX)</p

Fig 2 -

(a, b) SE images of water ice sample and indenter tip prior to experiments. Note image distortion generated by the electromagnetic interference of the Sm-Co magnet.</p

Representative load versus indenter displacement curve of experiments performed on water ice sample with diamond Berkovich nanoindentation tip.

Representative load versus indenter displacement curve of experiments performed on water ice sample with diamond Berkovich nanoindentation tip.</p

Fig 1 -

Schematic diagram of the experimental setup for in situ instrumented nanoindentation experiments of water ice (a). Photographs of the Alemnis LTM-CRYO indentation device (supplied by Alemnis AG) (b) and sample holder (c).</p

Revealing Compositional Evolution of PdAu Electrocatalyst by Atom Probe Tomography

Pd-based electro-catalysts are a key component to improve the methanol oxidation reaction (MOR) kinetics from alcohol fuel cells. However, the performance of such catalysts is degraded over time. To understand the microstructural/atomic scale chemical changes responsible for such an effect, scanning (transmission) electron microscopy measurements and atom probe tomography were performed after accelerated degradation tests. No morphological changes are observed after 1000 MOR cycles. In contrast, (1) Pd and B are leached from PdAu nanoparticles and (2) Au-rich regions are formed at the surface of the catalyst. These insights highlight the importance of understanding the chemical modification occurring upon MOR to design new catalysts

Exploring the Surface Segregation of Rh Dopants in PtNi Nanoparticles through Atom Probe Tomography Analysis

Proton-exchange membrane fuel cells hold promise as energy conversion devices for hydrogen-based power generation and storage. However, the slow kinetics of oxygen reduction at the cathode imposes the need for highly active catalysts, typically Pt or Pt based, with a large available area. The scarcity of Pt increases the deployment and operational cost, driving the development of novel highly active material systems. As an alternative, a Rh-doped PtNi nanoparticle has been suggested as a promising oxygen reduction catalyst, but the three-dimensional distributions of constituent elements in the nanoparticles have remained unclear, making it difficult to guide property optimization. Here, a combination of advanced microscopy and microanalysis techniques is used to study the Rh distribution in the PtNi nanoparticles, and Rh surface segregation is revealed, even with an overall Rh content below 2 at. %. Our findings suggest that doping and surface chemistry must be carefully investigated to establish a clear link with catalytic activity that can truly be established

A flowchart of the BooT-PCA on an aluminum bi-crystal dataset: Firstly, image processing is performed on a series of detector hit maps, secondly tracking and line detection are performed.

Next the collected data is reconstructed into 3D Cartesian coordinates, thirdly, a slope filter, PCA and triangulation (consists of mesh vertices) are applied sequentially to filter out zone lines atoms and fully reconstruct the GB surface.</p

Principle of the <i>boosting</i> tracker: At each frame, positive and negative samples are collected and fed into the <i>boosting</i> algorithm to create a strong classifier, then the classifier predicts the position of the target in the next frame.

(Xn, 1/0) indicates group n that contains either positive (1) or negative (0) samples.</p

3D nanostructural characterisation of grain boundaries in atom probe data utilising machine learning methods - Fig 9

(a) TAPSim specimen geometry. The grain boundary normal is set to nh (Eq 1). (b) Reconstruction from TAPsim detector hit map using BooT-PCA.</p