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The nature of hot electrons generated by exothermic catalytic reactions
Nedrygailov, I.I.,Park, J.Y. North Holland 2016 Chemical physics letters Vol.645 No.-
<P>We review recent progress in studies of the nature of hot electrons generated in metal nanoparticles and thin films on oxide supports and their role in heterogeneous catalysis. We show that the creation of hot electrons and their transport across the metal-oxide interface is an inherent component of energy dissipation accompanying catalytic and photocatalytic surface reactions. The intensity of hot electron flow is well correlated with turnover rates of corresponding reactions. We also show that controlling the flow of hot electrons crossing the interface can lead to the control of chemical reaction rates. Finally, we discuss perspectives of hot-electron-mediated surface chemistry that promise the capability to drive catalytic reactions with enhanced efficiency and selectivity through electron-mediated, non-thermal processes. (C) 2015 Elsevier B.V. All rights reserved.</P>
Lee, Hyosun,Nedrygailov, Ievgen I.,Lee, Young Keun,Lee, Changhwan,Choi, Hongkyw,Choi, Jin Sik,Choi, Choon-Gi,Park, Jeong Young American Chemical Society 2016 NANO LETTERS Vol.16 No.3
<P>Direct detection of hot electrons generated by exothermic surface reactions on nanocatalysts is an effective strategy to obtain insight into electronic excitation during chemical reactions. For this purpose, we fabricated a novel catalytic nanodiode based on a Schottky junction between a single layer of graphene and an n-type TiO2 layer that enables the detection of hot electron flows produced by hydrogen oxidation on Pt nanoparticles. By making a comparative analysis of data obtained from measuring the hot electron current (chemicurrent) and turnover frequency, we demonstrate that graphene's unique electronic structure and extraordinary material properties, including its atomically thin nature and ballistic electron transport, allow improved conductivity at the interface between the catalytic Pt nanoparticles and the support. Thereby, graphene-based nanodiodes offer an effective and facile way to approach the study of chemical energy conversion mechanisms in composite catalysts with carbon-based supports.</P>
Lee, Seung Hee,Nedrygailov, Ievgen I.,Oh, Sunyoung,Park, Jeong Young Elsevier 2018 CATALYSIS TODAY - Vol.303 No.-
<P><B>Abstract</B></P> <P>Hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) is an effective oxidizing agent that is commonly used in industry. In the presence of metal catalysts, H<SUB>2</SUB>O<SUB>2</SUB> can decompose into water and oxygen. Understanding this process at a fundamental level is extremely important for a number of industrial applications, e.g. the direct synthesis of H<SUB>2</SUB>O<SUB>2</SUB> from H<SUB>2</SUB> and O<SUB>2</SUB>. Here, we studied the rates of H<SUB>2</SUB>O<SUB>2</SUB> decomposition on Pt/n-Si catalysts using a chemicurrent approach that is based on the detection of hot electrons created during dissociative adsorption of H<SUB>2</SUB>O<SUB>2</SUB> molecules on platinum. We showed that both the rate of H<SUB>2</SUB>O<SUB>2</SUB> decomposition and the corresponding chemicurrent are sensitive to the pH of the reactive solution. This phenomenon is explained by variation of the potential barrier for electron transfer at the Pt/solution interface caused by adsorption of H<SUP>+</SUP> and OH<SUP>−</SUP> species from the solution on the catalytic surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hot electrons at liquid–solid interfaces during H<SUB>2</SUB>O<SUB>2</SUB> decomposition are probed. </LI> <LI> Pt/n-Si catalytic nanodiodes are fabricated for hot electron detection. </LI> <LI> PH effect on the rate of charge transfer during H<SUB>2</SUB>O<SUB>2</SUB> decomposition is studied. </LI> <LI> We show that charge transfer is more intensive in acidic H<SUB>2</SUB>O<SUB>2</SUB> solutions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Enhancement of Hot Electron Flow in Plasmonic Nanodiodes by Incorporating PbS Quantum Dots
Lee, Changhwan,Choi, Hyekyoung,Nedrygailov, Ievgen I.,Lee, Young Keun,Jeong, Sohee,Park, Jeong Young American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.5
<P>The enhancement, of hot electron generation using plasmonic nanostructures is a promising strategy for developing photovoltaic devices. Here, we show that hot electron flow generated in plasmonic Au/TiO2 nanodiodes by incident light can be amplified when PbS quantum dots are deposited onto the surface of the nanodiodes. The effect is attributed to efficient extraction of hot electrons via a three-dimensional Schottky barrier, thus giving new pathways for hot electron transfer. We also demonstrate a correlation between the photocurrent and Schottky barrier height when using PbS quantum dots with varying size and, ligand treatments that allow us to control the electric properties, (e.g., band gap. and Fermi, level, respectively) of the PbS quantum dots. This simple method introduces a new technique for further improving the power conversion efficiency of thin-film photovoltaic devices.</P>