Electronic Switching between Hot Electrons and Hot Holes via Schottky Junctions during Chemical Reactions.

Hot carriers, generated through nonadiabatic energy dissipation during exothermic catalytic reactions, play a pivotal role in enhancing catalytic performance. Upon generation, hot electrons typically reside in the sp-band above the Fermi level, while hot holes are formed in the -band below the Fermi level, following the energy distribution of the metal's electronic structure. However, it has been technically challenging to simultaneously capture and understand the flow of these two opposite charges during chemical reactions.

Revealing the Loss Mechanism of Chemically-Induced Hot Electron Transport.

Hot electrons are crucial for unraveling the intrinsic relationship between chemical reactions and charge transfer in heterogeneous catalysis. Significant research focused on real-time detection of reaction-driven hot electron flow (chemicurrent) to elucidate the energy conversion mechanisms, but it remains elusive because carrier generation contributes to only part of the entire process. Here, a theoretical model for quantifying the chemicurrent yield is presented by clarifying the contributions of hot carrier losses from the internal emission and multiple reflections.

Enhanced Hot Electron Flow and Catalytic Synergy by Engineering Core-Shell Structures on Au-Pd Nanocatalysts.

The synergistic catalytic performances of bimetallic catalysts are often attributed to the reaction mechanism associated with the alloying process of the catalytic metals. Chemically induced hot electron flux is strongly correlated with catalytic activity, and the interference between two metals at the atomic level can have a huge impact on the hot electron generation on the bimetallic catalysts. In this study, we investigate the correlation between catalytic synergy and hot electron chemistry driven by the electron coupling effect using a model system of Au-Pd bimetallic nanoparticles.

Catalytic Boosting by Surface-Plasmon-Driven Hot Electrons on Antenna-Reactor Schottky Nanodiodes.

Significant research has focused on enhancing catalytic performance through solar energy conversion, and the design of photocatalysis incorporating surface plasmons is drawing considerable attention as a highly competitive catalyst system. Although the hot electron process is the primary mechanism in plasmonic photocatalysis, the precise function of hot electron transport in catalytic reactions remains unclear due to the absence of direct measurement. Here, we demonstrate the intrinsic relationship between surface-plasmon-driven hot electrons and catalytic activity during hydrogen oxidation, utilizing catalytic Schottky nanodiodes (Pt/Ag/TiO) for antenna-reactor plasmonic photocatalysis.

Hot Electron Phenomena at Solid-Liquid Interfaces.

Understanding the role of energy dissipation and charge transfer under exothermic chemical reactions on metal catalyst surfaces is important for elucidating the fundamental phenomena at solid-gas and solid-liquid interfaces. Recently, many surface chemistry studies have been conducted on the solid-liquid interface, so correlating electronic excitation in the liquid-phase with the reaction mechanism plays a crucial role in heterogeneous catalysis. In this review, we introduce the detection principle of electron transfer at the solid-liquid interface by developing cutting-edge technologies with metal-semiconductor Schottky nanodiodes.

Electronic Control of Hot Electron Transport Using Modified Schottky Barriers in Metal-Semiconductor Nanodiodes.

Hot electron flux, generated by both incident light energy and the heat of the catalytic reaction, is a major element for energy conversion at the surface. Controlling hot electron flux in a reversible manner is extremely important for achieving high energy conversion efficiency. Here we demonstrate that hot electron flux can be controlled by tuning the Schottky barrier height.

Hot Electron Transport on Three-Dimensional Pt/Mesoporous TiO Schottky Nanodiodes.

We present the design of a three-dimensional Pt/mesoporous TiO Schottky nanodiode that can capture hot electrons more effectively, compared with a typical two-dimensional Schottky diode. Both chemically induced and photon-induced hot electrons were measured on the three-dimensional Pt/mesoporous TiO Schottky nanodiode. An increase in the number of interfacial sites between the platinum and support oxide affects the collection of hot electrons generated by both the catalytic reaction and light injection.

Enhanced hot electron generation by inverse metal-oxide interfaces on catalytic nanodiode.

Identifying the electronic behavior of metal-oxide interfaces is essential for understanding the origin of catalytic properties and for engineering catalyst structures with the desired reactivity. For a mechanistic understanding of hot electron dynamics at inverse oxide/metal interfaces, we employed a new catalytic nanodiode by combining Co3O4 nanocubes (NCs) with a Pt/TiO2 nanodiode that exhibits nanoscale metal-oxide interfaces. We show that the chemicurrent, which is well correlated with the catalytic activity, is enhanced at the inverse oxide/metal (CoO/Pt) interfaces during H2 oxidation.

Enhancing hot electron collection with nanotube-based three-dimensional catalytic nanodiode under hydrogen oxidation.

A novel three-dimensional catalytic nanodiode composed of a Pt thin film on TiO nanotubes was designed for the efficient detection of the flux of hot electrons, or chemicurrent, under hydrogen oxidation. We verify a significant increase in the chemicurrent from the fast transport of electrons across the ordered supporting oxide layer. This study demonstrates the direct detection of hot electrons on well-ordered TiO nanotubes during the catalytic reaction.