Recent reports of hot-electron-induced dissociation of small molecules, such as hydrogen, demonstrate the potential of using plasmonic nanostructures to convert light into chemical energy for low temperature catalytic reactions1. Theories have typically assumed that plasmonic catalysis is governed by the excitation of energized electrons or holes through the dephasing of localized surface plasmon resonance (LSPR) of Au, Al and Ag nanoparticles and charge transfer from the plasmonic metals to the adsorbed molecules2. However, LSPR-induced gas molecule dissociations have not been captured at the sub-nanostructure (nanometer) scale to resolve the location of adsorption sites on metal surfaces, which in turn may be the catalytically active sites for these chemical events. Here, we show the important role of gas adsorption for the LSPR-driven chemical reactions. We the use of an engineered plasmonic nanostructure based on theoretical predictions, including density-functional theory (DFT) calculations and plasmonic nanoparticle simulations, and in situ electron energy loss spectroscopy (EELS) in an environmental scanning transmission electron microscope (ESTEM) to investigate the surface- plasmon-assisted CO disproportionation reaction on the selective edges of triangular gold nanoprisms at room temperature. The study sheds light on how hot carriers overcome the limitations of a picosecond lifetime and transmit energy to the reactants at the gas-solid interfaces. Most importantly, we believe our work will spur the development of plasmonic catalyst structures that significantly reduce the energy consumption in large-scale reactions.
CO disproportionation, Local surface plasmon resonance, Au nanoprism, environmental transmission electron microscope, electron energy-loss spectroscopy