Marrying SPR excitation and metal–support interactions: unravelling the contribution of active surface species in plasmonic catalysis

Abstract

Plasmonic catalysis takes advantage of the surface plasmon resonance (SPR) excitation to drive or accelerate chemical transformations. In addition to the plasmonic component, the control over metal-support interactions in these catalysts is expected to strongly influence the performances. For example, CeO2 has been widely employed towards oxidation reactions due to its oxygen mobility and storage properties, which allow for the formation of Ce3+ sites and adsorbed oxygen species from metal-support interactions. It is anticipated that these species may be activated by the SPR excitation and contribute to the catalytic activity of the material. Thus, a clear understanding of the role played by the SPR-mediated activation of surface oxide species at the metal-support interface is needed in order to take advantage of this phenomenon. Herein, we describe and quantify the contribution from active surface oxide species at the metal-support interface (relative to O2 from air) to the activities in green SPR-mediated oxidation reactions. We employed CeO2 decorated with Au NPs (Au/CeO2) as a model plasmonic catalyst and the oxidation of p-aminothiophenol (PATP) and aniline as proof-of-concept transformations. We compared the results with SiO2 decorated with Au NPs (Au/SiO2), in which the formation of surface oxide species at the metal-support interface is not expected. We found that the SPR-mediated activation of surface oxide species at the metal-support interface in Au/CeO2 played a pivotal role in the detected activities, being even higher than the contribution coming from the activation of O2 from air.

Hot Electrons, Hot Holes, or Both? Tandem Synthesis of Imines Driven by the Plasmonic Excitation in Au/CeO2 Nanorods

“…It can be observed that CeO2 samples absorb light in the near-visible UV (<450 nm) [8]. Upon Au deposition, a band in the visible (≈550 nm) appears due to the LSPR dipolar mode in Au NPs [8,12]. Raman and XPS spectroscopies were employed to probe the metal-support interactions and oxygen vacancy properties in CeO2 and Au/CeO2 nanomaterials.…”

“…It can be observed that CeO 2 samples absorb light in the near-visible UV (<450 nm) [ 8 ]. Upon Au deposition, a band in the visible (≈550 nm) appears due to the LSPR dipolar mode in Au NPs [ 8 , 12 ].…”

“…This provides sufficient energy to initiate, accelerate, and/or control molecular transformations [9,10]. For metals such as Ag, Au, Al, and Cu, the LSPR excitation can take place in the visible range [11,12]. Interestingly, the combination of CeO 2 and plasmonic NPs, such as Au, can provide opportunities for not only achieving improved performance but also opening up reaction pathways under light-excitation that are not accessible via external heating [13][14][15][16][17][18].…”

Plasmonic colloidosomes of black gold for solar energy harvesting and hotspots directed catalysis for CO2 to fuel conversion

“…[7][8][9] Camargo's group, on the other hand, showed the tuning of activity and selectivity of plasmonic gold nanoparticles for organic transformations by the concept of hybrid materials and metal-support interactions. [10][11][12] Tuning the LSPR of the material to optimize the electromagnetic (EM) and thermal hotspots has scientic and technological advantages. Plasmonic coupling, a near-eld coupling of the dipoles in the presence of light, can also be tuned by modifying the gap/distance between NPs.…”

Gold and gold-palladium branched nanocrystals for applications in plasmonic catalysis and electrocatalysis

“…The gold nanourchins, nanodendrites, and nanospheres were impregnated on commercial SiO2 by the incipient wetness impregnation method. 42 For this procedure, the suspension of each nanostructure was batched synthesized (an appropriated amount to obtain 300 mg 2 wt.% Au/SiO2) and concentrated in 5 mL of ethanol. The commercial SiO2…”