<p>Title :</p>
<p>Carbon-Fixation by Plasmonic Catalysts</p>
<p>Abstract :</p>
<p style="text-align: justify;">Mimicking plant photosynthesis requires a synthetic photocatalyst that absorbs sunlight and uses that energy efficiently to convert CO<sub>2</sub> into energy-dense hydrocarbons. My talk will make the case that noble metal nanostructures, which exhibit collective free electron resonances called plasmons, may be well-suited to this task. Not only do plasmonic nanoparticles of Au, Ag, and Cu offer a means to absorb visible light efficiently, their strong-light-matter interaction can be paired with their ability to activate small molecules, such as CO<sub>2</sub>. We have had preliminary success with plasmonic catalysts, which under visible-light-excitation, can drive kinetically challenging multi-electron multi-proton processes such as methane generation. Moreover, the product selectivity is controllable by the nature of the exciting light, which suggests that a novel phenomenon is at work. In order to understand the light-driven pathway for CO<sub>2</sub> reduction, we have probed with single-site spatial resolution the dynamics of a plasmonic photocatalyst under operando conditions. From captured intermediates and density functional theory simulations, we are beginning to understand the mechanism which plasmonic excitation activates physisorbed CO<sub>2</sub>. It is clear that a close interplay between photoexcited states and surfaces is involved in this scheme of artificial photosynthesis. </p>