Direct Photocatalysis by Plasmonic Nanostructures

Abstract

Recent reports have shown that plasmonic nanostructures can be used to drive direct photocatalysis with visible photons, where nanostructures act as the light absorber and the catalytic active site. These reports have showcased direct plasmon driven photocatalysis as a route to concentrate and channel the energy of low intensity visible light into adsorbed molecules, enhancing the rates of chemical transformations, and offering pathways to control reaction selectivity. In this perspective, we will discuss the fundamental photophysics of localized surface plasmon resonance (LSPR) excitation in the context of driving chemical transformations. The various demonstrated chemical conversions executed using direct plasmonic photocatalysis will be reviewed. Experimental observations, such as the dependence of photocatalytic rate on illumination intensity and photon energy, will be related to microscopic mechanisms of photocatalysis. In addition, theoretical treatments of various mechanisms within the process of direct plasmonic photocatalysis will be discussed and related to experimental studies. Throughout the Perspective, the possibility of activating targeted adsorbate bonds to allow rational manipulation of reaction selectivity in direct plasmonic photocatalysis will be discussed.

Solar-Powered Plasmon-Enhanced Heterogeneous Catalysis

“…This mechanism stabilizes the photogenerated charges in the metal co-catalyst and extends their lifetime so that they can drive the chemical transformation. Most importantly, it was realized that using Au NPs as co-catalyst, an additional increase in the process efficiency could be obtained [32,39]. Au NPs can harvest visible light owing to LSPR and thus provide two simultaneous pathways for the enhancement of the photocatalytic reaction efficiency: (a) increased charge separation in the semiconductor (with Au NPs working as an electron sink) and (b) surface sensitization effect (due to LSPR).…”

“…The fundamental signature of plasmonic enhancement, both via hot electron transfer and field enhancement is that the action spectrum shape (reaction quantum efficiency as a function of the illumination wavelength) resembles the LSPR absorption line shape [32,39,[46][47][48][49][50][51][52].…”

Methods of photoelectrode characterization with high spatial and temporal resolution

“…Localized surface plasmon resonance (LSPR) is a well-recognized phenomenon in noble metal nanoparticles and nanostructured surfaces due to collective oscillation of conduction electrons under optical excitation, and has been exploited for a variety of applications, including (electro)catalysis. [135][136][137][138][139] When optically excited, the surface plasmons re-emit their energy radiatively (i.e. scattering) at their resonant wavelength or non-radiatively (i.e.…”

Morphology‐controlled Electrodeposition of Copper Nanospheres onto FTO for Enhanced Photocatalytic Hydrogen Production

“…Conventional photocatalysts are almost exclusively focused on the study of inorganic semiconductor materials such as TiO 2 , [9][10][11][12][13][14] however, poor light absorption and the fast electron/hole recombination [15] limited the use of these photocatalysts. To overcome these problems, great efforts have recently been devoted to using plasmonic metallic nanostructures in the field of photocatalysis [16][17][18][19][20][21] due to their surface plasmon resonance property [22,23] which is beneficial for light absorption and increase of photogenerated charge carriers energy intensity under visible light irradiation. Dong et al found that Bi nanostructure exhibited a remarkable and stable photocatalytic activity due to its surface plasmon resonance.…”