Controlled nanocatalysis requires novel approaches to understand the size-dependence of catalytic processes. We report on a one-to-one structure analysis of a single platinum (Pt) nanodot-array supported by a strontium titanate STO(100) single crystal by real-space imaging in a scanning electron microscope and in reciprocal space using coherent Bragg diffraction from a focused X-ray beam at PETRA III at DESY.
The Pt nanodot-array was created using a combined lift-off and etching process based on electron-beam lithography. Utilizing a transfer and re-positioning protocol using the Pt X-ray fluorescence signal we localized the 2x2 mu² array with a center-center distance of 150 nm between single Pt nanodots. The Pt(111) Bragg peak position indicates a preferential Pt(111)/STO(100) orientation. The interference fringes of this peak are typical for coherent diffraction and allow extracting particle shape, size and interparticle distance to compare with the real space imaging.
We propose the use of such nanodot-arrays for future experiments on in-situ oxidation or catalysis as well as for coherent X-ray diffraction of single nano-assemblies under reaction conditions.