Enhancing Photothermal Effect and Stability of Plasmonic Pd/Ag-Nanosheet by Nanoassembly for Efficient Light- Driven Catalytic Organic Hydrogenation

摘要

Due to the ability to harness surface plasmons to promote solar-to-chemical energy conversion, plasmonic nanoparticles with finely-controlled structure and optical properties hold great promise for light-activated catalysis. Herein, we prepared a strong plasmonic nanostructure, by assembling Pd/Ag nano- sheets (NSs) with varied Pd/Ag ratio onto the surface of polystyrene (PS) microsphere to form a spherical nanoassembly (NAs). The as-prepared Pd/Ag-PS NAs showed better photo- thermal performance than the precursor Pd/Ag NSs of the same concentration. More importantly, the as-prepared Pd/Ag- PS NAs can be used to boost light-driven organic hydro- genation reactions, in which Pd nanocomponent acts as hydrogenation reaction active sites and Pd/Ag-NSs can convert light efficiently into heat. Under room temperature conditions, the light-driven catalytic hydrogenation efficiency under 50 mW/cm2 full-spectrum irradiation proved to be comparable to that of thermally (70 °C) driven reactions. Moreover, the as- prepared Pd/Ag-PS NAs has better photostability than Pd/Ag NSs. The results proved that the photothermal effect rather than the transfer of hot electrons is responsible for enhanced photocatalytic hydrogenation performance. The strong plas- mon coupling between closely-packed Pd/Ag NSs enhances the electromagnetic field intensity and scattering intensity and increase Vis-NIR light trapping and high density hot spots generation, which lead to an overall better photocatalytic efficiency.