Hot Electron and Surface Plasmon-Driven Catalytic Reaction in Metal-Semiconductor Nanostructures

Abstract

A pulse of high kinetic energy electrons (1-3 eV) in metals can be generated after surface exposure to external energy, such as the absorption of light or exothermic chemical processes. These energetic electrons are not at thermal equilibrium with the metal atoms and are called "hot electrons". The detection of hot electrons and understanding the correlation between hot electron generation and surface phenomena are challenging questions in the surface science and catalysis community. Hot electron flow generated on a gold thin film by photon absorption (or internal photoemission) appears to be correlated with localized surface plasmon resonance. In this perspective, we outline recent research activities to develop energy conversion devices based on hot electrons and surface plasmons. The chemicurrent or hot electron flows correlate well with the turnover rate of CO oxidation or hydrogen oxidation, measured separately by gas chromatography, suggesting an intrinsic relation between the catalytic reaction and hot electron generation. Photon energy can be directly converted to hot electron flow through the metal-semiconductor interface of Pt/TiO2. The flow of hot charge carriers influences the chemistry at the oxide-metal interface and the turnover rate in the chemical reaction on metal-semiconductor nanostructures. The effect of surface plasmons on the catalytic and photocatalytic activity on metal-oxide hybrid nanocatalysts is also highlighted.