Direct Fabrication of Polycrystalline Γ-Alumina Nanochains-Supported Pt Nanoparticles on Macroscopic Ceramic Substrates and In-Situ Tem Observation of Their Physiochemical Phenomena with the Supply of Co at 300oc

Abstract

We report the direct fabrication of polycrystalline γ-Al2O3 nanochains-supported Pt nanoparticles on macroscopic substrates, such as monolithic honeycombs and porous disc-typed ceramics, via chemical vapor deposition. We also investigate solid-gas reactions between the γ-Al2O3 nanochains@Pt nanoparticles and CO using in-situ transmission electron microscopy (TEM). The SEM, TEM, STEM, and XRD patterns reveal that γ-Al2O3 nanochains, 80 nm in diameter, were uniformly formed on the surfaces of macroscopic ceramic substrates. High-resolution TEM (HTEM) images confirm the polycrystalline and kinking structures connecting the nanochains. The coating thickness of γ-Al2O3 nanochains layer is approximately 100㎛. The EDX images and XPS graphs indicate that Pt nanoparticles, 3.5 nm in diameter, are well-coated on the surfaces of the γ-Al2O3 nanochains. The uniform distribution of Pt nanoparticles is precisely controlled utilizing autogenic pressure reaction. Additionally, in-situ observation significantly highlights the physicochemical phenomena of the γ-Al2O3 nanochains@Pt nanoparticles over time under CO supply at 300°C. Coke formation was accelerated on the surface of catalysts as increase of CO partial pressure increase, while Pt nanoparticles is very stable without the migration and aggregation

Keywords: autogenic pressure reaction, physicochemical phenomena, Pt, γ-Al2O3 nanochains