Plasmonic Harvesting of Light Energy for Suzuki Coupling Reactions

Abstract

The efficient use of solar energy has received wide interest due to increasing energy and environmental concerns. A potential means in chemistry is sunlight-driven catalytic reactions. We report here on the direct harvesting of visible-to-near-infrared light for chemical reactions by use of plasmonic Au-Pd nanostructures. The intimate integration of plasmonic Au nanorods with catalytic Pd nanoparticles through seeded growth enabled efficient light harvesting for catalytic reactions on the nanostructures. Upon plasmon excitation, catalytic reactions were induced and accelerated through both plasmonic photocatalysis and photothermal conversion. Under the illumination of an 809 nm laser at 1.68 W, the yield of the Suzuki coupling reaction was ~2 times that obtained when the reaction was thermally heated to the same temperature. Moreover, the yield was also ~2 times that obtained from Au-TiOx-Pd nanostructures under the same laser illumination, where a 25-nm-thick TiOx shell was introduced to prevent the photocatalysis process. This is a more direct comparison between the effect of joint plasmonic photocatalysis and photothermal conversion with that of sole photothermal conversion. The contribution of plasmonic photocatalysis became larger when the laser illumination was at the plasmon resonance wavelength. It increased when the power of the incident laser at the plasmon resonance was raised. Differently sized Au-Pd nanostructures were further designed and mixed together to make the mixture light-responsive over the visible to near-infrared region. In the presence of the mixture, the reactions were completed within 2 h under sunlight, while almost no reactions occurred in the dark.

Hot‐Electron‐Mediated Photochemical Reactions: Principles, Recent Advances, and Challenges

“…By having a higher energy than the normal electrons they are therefore easier to inject into organic molecules to break the chemical bonds. [38] The individual roles of the heating and hot electron effects were previously under debate since these two effects are usually entangled. Recently, Huang et al experimentally proved that hot electrons sometimes affect plasmon-induced organic synthesis negatively.…”

“…[38,[132][133][134][135][136][137][138][139][140][141][142][143][144][145][146][147] Several reports focused on the photocatalytic degradation of organic compounds. [132][133][134][135][136][137] In a typical degradation reaction, the photogenerated electrons convert oxygen (O 2 ) to superoxide radicals (HO 2 • ), with the photogenerated holes simultaneously forming hydroxyl radicals (OH • ) by reacting with H 2 O.…”

“…[38] By combining the plasmonic and catalytic components in a single hybrid nanostructure, the light energy could be harvested by the plasmonic component (Au), and the generated hot electrons could be directly transferred to the catalytic component (Pd), inducing Suzuki coupling. In addition to plasmonic photocatalysts, the catalytic reactions were also triggered and promoted by photothermal conversion.…”

Solar-Powered Plasmon-Enhanced Heterogeneous Catalysis

“…On the other hand, the Cu oxidation followed by the restoration of Cu by Au LSPR prompted the overall oxidation process on Au-Cu/TiO 2 heterostructures [134]. Unsupported Au nanorods decorated with multiple Pd NPs were found to harvest vis-to-NIR light for Suzuki coupling (i.e., C-C formation for poly-olefins synthesis) under 809-nm laser irradiation [136]. Au acted as the plasmonic component for visible light absorption, while Pd was the effective catalyst for Suzuki coupling.…”

Platinum-coated Core-Shell Gold Nanorods as Multifunctional Orientation Sensors in Differential Interference Contrast Microscopy

“…So far, the bimetallic core-shell gold nanorods have been widely used as a catalyst that provides greater catalytic efficiency than a monometallic system. [28][29][30][31][32][33] However, there have been few studies to investigate bimetallic core-shell structures as orientation probes for single-particle rotational tracking. In this regard, it is highly desirable to have a deeper insight into the optical properties of bimetallic core-shell gold nanorods at the single-particle level, and to examine their potential use for developing multifunctional orientation probes under optical microscopy.…”