Indirect to Direct Charge Transfer Transition in Plasmon‐Enabled CO₂ Photoreduction

Abstract

Understanding hot carrier dynamics between plasmonic nanomaterials and its adsorbate is of great importance for plasmon‐enhanced photoelectronic processes such as photocatalysis, optical sensing and spectroscopic analysis. However, it is often challenging to identify specific dominant mechanisms for a given process because of the complex pathways and ultrafast interactive dynamics of the photoelectrons. Here, using CO2 reduction as an example, the underlying mechanisms of plasmon‐driven catalysis at the single‐molecule level using time‐dependent density functional theory calculations is clearly probed. The CO2 molecule adsorbed on two typical nanoclusters, Ag20 and Ag147, is photoreduced by optically excited plasmon, accompanied by the excitation of asymmetric stretching and bending modes of CO2. A nonlinear relationship has been identified between laser intensity and reaction rate, demonstrating a synergic interplay and transition from indirect hot‐electron transfer to direct charge transfer, enacted by strong localized surface plasmons. These findings offer new insights for CO2 photoreduction and for the design of effective pathways toward highly efficient plasmon‐mediated photocatalysis.

Efficient Production of Solar Hydrogen Peroxide Using Piezoelectric Polarization and Photoinduced Charge Transfer of Nanopiezoelectrics Sensitized by Carbon Quantum Dots

“…These trends are different from the cooperation of indirect hot electron transfer and direct charge transfer initiated by localized surface plasmons in Ag 20 and Ag 147 nanoclusters leading to an efficient CO 2 photoreduction in another study. [ 55 ] In the systems studied here, the effective carrier concentration involved in the piezophotocatalysis was influenced by the piezophototronic effect. However, there is no specific mechanism to explain the effect of piezoelectric polarization on the kinetics of the piezophotocatalytic reactions, so further studies are needed to clarify potential generality.…”

Thermo-photo catalysis: a whole greater than the sum of its parts

“…Here, mechanistic distinction is essential for developing highly efficient plasmonmediated catalytic processes due to the different optimization considerations on electromagnetic field strength either at the surface (direct) or inside (indirect) the nanostructure. 263,264 The intramolecular HOMO-LUMO transition of reactant molecule leads to an increased polarizability and thereby its response to plasmonic field gradient, which enhances its adsorption on catalyst and may further tune catalytic selectivity. 56,262,265 Namely, species with a stronger light absorption to transform into excited state may experience a stronger plasmon-based force of attraction, which adds up to general van der Waals force to overcome its Brownian motion, showing a greater coverage on catalyst surface and thus being converted more favourably.…”

“…Here, mechanistic distinction is essential for developing highly efficient plasmon-mediated catalytic processes due to the different optimization considerations on electromagnetic field strength either at the surface (direct) or inside (indirect) the nanostructure. 263,264…”

Theoretical Investigations on the Plasmon-Mediated Dissociation of Small Molecules in the Presence of Silver Atomic Wires

“…Others may examine realistically sized nanocluster−adsorbate systems with local density or generalized gradient-based functionals. 37 In these cases, similar to the jellium case, dissociation is achieved upon excitation at the quantum plasmon mode at a high electric field strength. Others still compute transition probabilities within the framework of electron-only dynamics rather than with explicit surfaces, which provides valuable information on electron−hole pairs and their probabilities of formation.…”

“…Others, like our previous work and that of Yan et al, rely on small clusters that share key properties with more realistically sized nanoclusters in order to retain computational tractability. Others may examine realistically sized nanocluster–adsorbate systems with local density or generalized gradient-based functionals . In these cases, similar to the jellium case, dissociation is achieved upon excitation at the quantum plasmon mode at a high electric field strength.…”