Pore Structure and Bifunctional Catalyst Activity of Overlayers Applied by Atomic Layer Deposition on Copper Nanoparticles

We present a model system, based on spherical nonporous supports, to facilitate the characterization of supported metal catalysts stabilized by atomic layer deposition (ALD) against sintering and leaching under liquid-phase conditions. Calcination at high temperatures (973 K) produces pores in the ALD overcoat, and we image these pores using scanning transmission electron microscopy and electron energy loss spectroscopy (STEM/EELS). We determine the size of these pores to be similar to 1 nm using small-angle X-ray scattering (SAXS). Finally, we demonstrate the use of ALD to synthesize novel bifunctional catalysts by the addition of an acidic oxide layer to the stabilizing overcoat.