Effects of thermal treatment on sea-urchin-like platinum nanoparticlese

Abstract

The size and shape of metallic nanoparticles significantly influence the focus of light illumination and affect the plasmonic energy transformation process in plasmonic photocatalytic reactions. This study examined the effects of thermal treatment on the surface shape and plasmonic enhancement of Pt nanoparticles. SEM and XRD results indicate that the nanosized protruding thrusts on the surfaces of Pt sea urchin particles have a lower chemical potential and higher activity. They can be melted and reshaped at 600℃, which is much lower than their melting point of over 1700 ℃. The XPS results suggest that thermal treatment at 600℃ does not cause additional oxidation of the Pt nanocrystals. The samples not subjected to high-temperature treatment exhibited notable photocatalytic degradation of methylene blue in water under UV illumination. These results demonstrate that the surface features of Pt sea urchin nanoparticles play an essential role in the photocatalytic degradation of methylene blue under UV light. Larger particles treated at high temperatures exhibited reduced photocatalytic processing efficiency, whereas smaller particles treated at a lower temperature exhibited increased efficiency, indicating that the protruding sharp cones enhance plasmonic effects in photocatalytic reactions.