Spark Ablation Generation of Metal Nanoparticles and Coating on TiO2 in the Aerosol Phase

Generation and characterisation of metal nanoparticles (NP) gained attention in recent years due to their significant potential in applications as diverse as catalysis, electronics or energy storage. Despite the high interest in NPs, their characterization is challenging and detailed quantitative information on size, number concentration and morphologies are key to understand their properties. In this study we generated NPs from four metals, Au, Pt, Cu and Ni, via spark ablation in the aerosol phase, which allows to produce NPs as small as 1 nm in high quantities and purity. Particles were characterised with transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX) as well as online aerosol particle size distribution measurement techniques. Particle modes for the four metals ranged between 3 nm and 4 nm right after generation. The number and size of particles generated correlated with thermal properties of the metals such as thermal or electrical conductivity. The four metal NPs were also coagulated with larger TiO2 NPs of about 120 nm size and the metal surface coverage of the TiO2 particles was characterised with electron microscopy and EDX spectroscopy.