Pulsed laser synthesis of highly active Ag-Rh and Ag-Pt antenna-reactor-type plasmonic catalysts.

Kenneth A Kane,Massimo F Bertino

doi:10.3762/bjnano.10.192

Abstract

Ag, Pt, and Rh monometallic colloids were produced via laser ablation. Separate Ag–Rh and Ag–Pt heterostructures were formed by mixing and resulted in groupings of Rh/Pt nanoparticles adsorbing to the concavities of the larger Ag nanostructures. The 400 nm Ag plasmonic absorption peak was slightly blue-shifted for Ag–Pt and red-shifted for Ag–Rh heterostructures. Catalytic activity for the reduction of 4-nitrophenol increased significantly for Ag–Pt and Ag–Rh compared to the monometallic constituents, and persisted at lower loading ratios and consecutive reduction cycles. The enhancement is attributed to the Rh and Pt nanoparticles forming antenna–reactor-type plasmonic catalysts with the Ag nanostructures.

Highlights

Metal nanoparticles can interact with visible light through an excitation of the localized surface plasmon resonance (LSPR)
Colloidal Ag–Rh/Pt heterostructures were obtained by mixing monometallic colloids generated using pulsed laser ablation
The enhancement is attributed to the Ag–Pt and Ag–Rh heterostructures forming multicomponent plasmonic catalysts through an antenna–reactor-type plasmonic interaction between the Ag nanostructures and the adsorbed Rh/Pt NPs

Summary

Introduction

Metal nanoparticles can interact with visible light through an excitation of the localized surface plasmon resonance (LSPR). A consequence of plasmon excitation is the direct confinement of light near the surface of the metal NP in the form of elevated electric fields [1]. The confinement amplifies absorption (electron–hole pair excitation) and photon scattering, both of which are photophysical processes [2,3,4,5]. Elevated LSPR fields dissipate energy through radiative photon scattering or nonradiative absorption [8,9,10]. Nonradiative absorption results in the generation of energetic charge carriers [11,12] and chemical bonds can be activated with the energy created by the charge carriers, documented by Christopher et al who reported partial oxidation reactions on plasmonic Ag NPs

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Conclusion