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Department of Chemistry College of Liberal Arts and Sciences

Manipulation of Hot Electrons at Metal-Semiconductor Interfaces for Enhanced Photocatalysis and Photoelectrochemical Energy Conversion

Plasmon-Driven Nanoparticles Growth

Image of an illuminate Au nanoprism with PVP on the edges accumulating electrons and holes in center transferring to a scavenger.
Zhai, Y. et al. Nature Materials, 2016, 15, 889-895
scanning electron microscopy (SEM) images of gold nano prisms, and nano starts and their synthesis intermediates.
Guo W. et al. J. Am. Chem. Soc. 2020, 142, 25, 10921–10925

Surface-Plasmon-Driven Hot Electron Photochemistry

Illustration of a gold nanoparticle attached to a semiconductor rod in water, showing charge transfer during photocatalysis. Labels mark the semiconductor valence band (VB) and conduction band (CB), and the adsorbed molecule’s HOMO and LUMO levels. Arrows indicate electron excitation in the gold nanoparticle and transfer between the nanoparticle, semiconductor, and surface-bound molecules.
Zhang, Y. et al., Chem. Rev. 2018 118, 2927-2954
Diagram comparing nanoparticle size effects on gold-decorated titanium dioxide (TiO2) for hydrogen production. A larger gold nanoparticle on the left shows more hole accumulation and favorable electron transfer over the Schottky Barrier, enabling proton reduction to H2, while a smaller gold nanoparticle on the right shows minimal electron transfer over the Schottky Barrier thus minimal hydrogen formation. The figure indicates that larger Au nanoparticles promote water-to-hydrogen conversion more effectively than smaller ones.
Qian, K. et al., J. Am. Chem. Soc. 2014 136, 9842-9845
Schematic of light-driven hydrogen production using an Au–TiO2 photocatalyst in water. Sunlight illuminates a beaker containing a layered Au–TiO2 material and a platinum electrode, producing hydrogen bubbles and electron flow through an external circuit. An inset shows a gold nanoparticle attached to TiO2 with energy levels, indicating photoexcited hot electrons injected from Au into TiO2.
DuChene, J.S. et al., Angew. Chem. Int. Ed. 2014, 53, 126
Illustration of a nickel–titanium dioxide (Ni–TiO2) particle submerged in water. The particle has a nickel sphere attached to a TiO2 rod, with blue electrons shown on the TiO2 side and red holes at the Ni/TiO2 interface. Methylene blue molecules in solution interact with electrons causing dye degradation.
He, S. et al., Angew. Chem. Int. Ed. 2019, 58, 6038 – 6041

Plasmon-Mediated Hole Transfer for Oxidation Reactions

Diagram of a photocatalytic reaction on a titanium dioxide (TiO₂) surface decorated with a gold (Au) nanoparticle. The TiO₂ lattice is shown as gray (Ti) and blue (O) spheres, with a yellow Au nanoparticle on the surface. Arrows indicate charge transfer, with a labeled hole (h⁺) transferring either to adjacent Ti sites with adsorbed hydroxide or through a hole-transfer mediator molecule, catechol, to generate O2. The holes transferring from the Au surface to hydroxide are blocked as indicated by an arrow with an X through it. This is indicated by the labeled Fermi level (EF) as holes can only transfer to adjacent TiO2 or catechol.
Zhang, Y. et al. manuscript in preparation
Illustration of a catalytic surface reaction showing carbon monoxide (CO) and oxygen (O₂) molecules interacting on a palladium (Pd) site supported by silver (Ag) atoms. A red-highlighted, indicating the photothermal heating, Pd cluster at the center binds reactant molecules, while arrows indicate the reaction producing carbon dioxide (CO₂), which then desorbs from the surface.
Qiu, J. et al. submitted to Angw. Chem. Int. Ed.