Synthetic methods that allow for the controlled design of well-defined Pt nanoparticles are highly desirable for fundamental catalysis research. In this work, we propose a strategy that allows precise and independent control of the Pt particle size and coverage. Our approach exploits the versatility of the atomic layer deposition (ALD) technique by combining two ALD processes for Pt using different reactants. The particle areal density is controlled by tailoring the number of ALD cycles using trimethyl(methylcyclopentadienyl)platinum and oxygen, while subsequent growth using the same Pt precursor in combination with nitrogen plasma allows for tuning of the particle size at the atomic level. The excellent control over the particle morphology is clearly demonstrated by means of in situ and ex situ X-ray fluorescence and grazing incidence small angle X-ray scattering experiments, providing information about the Pt loading, average particle dimensions, and mean center-to-center particle distance.

Aluminium phosphate thin films were deposited by plasma-assisted atomic layer deposition (ALD) using a sequence of trimethyl phosphate (TMP, Me 3 PO 4 ) plasma, O 2 plasma and trimethylaluminium (TMA, Me 3 Al) exposures. In-situ characterization was performed, including spectroscopic ellipsometry, optical emission spectroscopy, mass spectrometry and FTIR. In the investigated temperature region between 50 • C and 320 • C, nucleation delays were absent and linear growth was observed, with the growth per cycle (GPC) being strongly dependent on temperature. The plasma polymerization of TMP was found to play an important role in this process, resulting in CVD-like behavior at low temperatures and ALD-like behavior at high temperatures. Films grown at 320 • C had a GPC of 3.7Å/cycle and consisted of amorphous * To whom correspondence should be addressed † Ghent University ‡ IMEC ¶ These authors contributed equally to this work 1 aluminium pyrophosphate (Al 4 P 6 O 21 ). They could be crystallized to triclinic AlPO 4 tridymite by annealing to 900 • C, as evidenced by high temperature XRD measurements. The use of a TMP plasma might open up the possibility of depositing many other metal phosphates by combining it with appropriate organometallic precursors.

This paper describes the design of a low-cost USB-controlled potentiostat/galvanostat which can measure or apply potentials in the range of ±8V, and measure or apply currents ranging from nanoamps to max. ±25 mA. Precision is excellent thanks to the on-board 20-bit D/A-convertor and 22-bit A/D-convertors. The dual control modes and its wide potential range make it especially suitable for battery characterization. As an example use case, measurements are presented on a lithium-ion test cell using thin-film anatase TiO2 as the working electrode. A cross-platform Python program may be used to run electrochemical experiments within an easy-to-use graphical user interface. Designed with an open hardware philosophy and using open-source tools, all the details of the project (including the schematic, PCB design, microcontroller firmware, and host computer software) are freely available, making custom modifications of the design straightforward.

A new plasma-enhanced atomic layer deposition process was developed to deposit iron phosphate by using a sequence of trimethyl phosphate (TMP, Me3PO4) plasma, O2 plasma, and tert-butylferrocene (TBF, Fe­(C5H5)­(C5H4C­(CH3)3)) exposures. Using in situ spectroscopic ellipsometry and ex situ X-ray reflectometry, the growth linearity, growth per cycle (GPC), and density of the resulting thin films was investigated as a function of the pulse times and the substrate temperature. At a substrate temperature of 300 °C and using saturated pulse times, an exceptionally high GPC of 1.1 nm/cycle without nucleation delay was achieved, resulting in amorphous films with an empirical stoichiometry of FeP1.5O4.7 with 0.9% hydrogen and no detectable carbon residue. Trigonal FePO4 (Berlinite) was formed upon annealing in air. Remarkably, annealing in helium resulted in the formation of elemental phosphorus. The as-deposited, amorphous material became active as a Li-ion cathode after an initial irreversible electrochemical lithiation, showing insertion and extraction of Li+ around a potential of 3.1 V vs Li/Li+. By conformally depositing the same material on a 3D-microstructured substrate consisting of Pt-coated Si micropillars, the capacity could be drastically increased without sacrificing rate performance.

Particle coarsening is the main cause for thermal deactivation and lifetime reduction of supported Pt nanocatalysts. Here, Atomic Layer Deposition (ALD) was used to prepare a model system of Pt nanoparticles with high control over the metal loading and the nanoparticle size and coverage. A series of samples with distinct as-deposited size and interparticle spacing was annealed under different oxygen environments while Grazing Incidence Small Angle X-ray Scattering (GISAXS) was employed as in situ tool for monitoring the change in average nanoparticle size. The obtained results revealed three morphological stages during the thermal treatment, which can be explained by (I) the formation of a PtO shell on stable Pt nanoparticles at low temperature (below 300 °C), (II) the reduction of the PtO shell at moderate temperature (300 to 600 °C), creating mobile species that trigger particle coarsening until a steady morphological state is reached, and (III) the evaporation of PtO at high temperature (above 650 °C), causing particle instability and coarsening reactivation. The onset temperatures for stages (II) and (III) were found to depend on the initial particle size and spacing as well as on the O partial pressure during annealing, and could be summarized in a morphological stability diagram for Pt nanoparticles. The coarsening model indicates an important role for the reduction of the PtO shell in inducing particle coarsening. The key role of the reduction process was corroborated through isothermal experiments under decreasing O partial pressure and through forced reduction experiments near room temperature via H exposure.