Key Factors for Controlling Plasmon-Induced Chemical Reactions on Metal Surfaces

Abstract

including the dielectric function, electronic states, and surface properties. Further investigations of plasmonic metal catalysts, both macroscopically and microscopically, provide more detailed fundamental knowledge on controlling plasmoninduced chemical reactions. In addition, the development of a theory to handle the entangled key factors, as well as a precise and large amount of experimental data for various materials and reactions, is required to establish a strategy for designing and customizing plasmonic metal catalysts.

Particle Size-Dependent Charge Transfer Dynamics for Boosting CO2 Photoreduction over Ag/TiO2 Heterojunction

“…Photocatalytic CO 2 reduction (PCO 2 R) is an effective solution of increasing energy shortage and environmental pollution, which is caused by excessive use of fossil fuels. − However, the reduction reaction of CO 2 requires a high negative potential. , Semiconductor catalysts are able to absorb light to create electron–hole pair separation, which are able to reduce CO 2 to economically valuable C1 and C2 products. , The catalytic efficiency of conventional semiconductor photocatalysts is limited due to their unsuitable energy band structure and poor light absorption. In light of these, a metal plasma is introduced on the surface of the semiconductor catalyst to form a Schottky junction, , which can effectively enhanced the visible light absorption due to the local surface plasmon resonance (LSPR). − The plasma is also regarded as an optical nanoantenna in the photocatalytic process. Up to now, the composition, assembly method, and geometry of the surface metal plasma have influenced the excitation process of hot electrons in Schottky junctions.…”

“…In light of these, a metal plasma is introduced on the surface of the semiconductor catalyst to form a Schottky junction, , which can effectively enhanced the visible light absorption due to the local surface plasmon resonance (LSPR). − The plasma is also regarded as an optical nanoantenna in the photocatalytic process. Up to now, the composition, assembly method, and geometry of the surface metal plasma have influenced the excitation process of hot electrons in Schottky junctions. Notably, the metal particle size is often easily overlooked but is important for the regulation of performance.…”

Vibrational Energy Flow in Molecules Attached to Plasmonic Nanoparticles

“…The ability to facilitate chemical reactions via interactions between light and molecules attached to or near metal nanoparticles has motivated many studies of photochemical and photophysical processes in these systems. − Plasmonic nanoparticles catalyze, e.g., dimerization, dissociation, and reduction of chemisorbed 4-nitrobenzenethiol (NBT), − accelerate enzyme catalysis, and can trigger reactions with medical applications. − While detailed mechanisms for the catalysis of these reactions remain unclear, there is evidence that vibrational energy flow plays a central role in the kinetics of many of them. The NO stretch of NBT has been the subject of particular interest, as selective excitation of this mode has been recently observed to drive dissociation, where the extent to which the reaction can be accelerated by selective excitation depends on vibrational energy flow .…”

“…There has been much debate about mechanisms by which chemical reactions can be catalyzed by plasmonic nanoparticles, often focusing on the roles of hot charge carriers transferred to nearby molecules and photothermal effects. − Excitation sources include the plasmonic electric field, hot carriers, and local heating, and the nature and shape of the nanomaterials can impact reaction progress . Regardless of how energy is introduced to the molecule attached to the plasmonic nanoparticle, vibrational dynamics and relaxation mediate chemical reaction kinetics. − The connection between vibrational relaxation and dissociation of NBT following plasmonic excitation has been made strikingly clear in a recent study by Kim and co-workers, who have demonstrated selective excitation of the NO stretch of NBT attached to gold.…”