At the outset of the project, we had a clear plan for how to achieve the project objectives, but we were otherwise starting from scratch. The first we did was to design and fabricate MEMS chips with large arrays of cavities which were TEM transparent. In parallel, we built up an AFM setup, and a laser interferometry setup for tracking the cavities. Using these tools we could reproduce some literature results on leak-tightness of 2D-chip interfaces towards gas; and going beyond the literature we expanded upon the set of investigated gasses and found the water-solubility of leaking gas to correlate with the leak rates. Beyond that, and using the TEM transparency, we developed a new technique based on EEL-Spectroscopy of the captive gas and used it to perform series of high-temperature leak-rate measurements. This enabled the extraction kinetic parameters of the (Arrhenius-type) leak-rate behavior; and it also enabled the explanation of much of the scatter and inconsistency in the literature.
What we did not achieve, within the limited time of ATOMICAR, was the measurement of catalytic turnover of captive nanoparticles, however, this work is currently ongoing in another project which is a direct continuation of the pioneering work done in ATOMICAR.
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Since the start of the project we have developed (from scratch) experimental facilities and methodology in order to start catalytic measurements on single, isolated nanoparticles. We have designed and fabricated Cavity Array Reactor (CAR) chips with micron-size cavities, which we seal gas-tight using 2-dimensional "sheets" of material.
We study the surface of he 2-dimensional material using Atomic Force Microscopy (AFM) in a custom setup, which we have established as part of the project.
We have made such CARs in a special version where the floor of the cavity is only a few tens of nanometers thick which makes it transparent to the electron beam in a Transmission Electron Microscope (TEM). Finally, we have built a laser-setup to study the mechanical properties of the 2-dimensional "sheets".
