Adsorbate Specificity in Hot Electron Driven Photochemistry on Catalytic Metal Surfaces

Visible light driven catalysis on metal surfaces and nanoparticles has attracted significant attention in recent years as a potential route for driving selective chemical reactions that are difficult to achieve with thermal energy. It is most often assumed that photochemistry on metal surfaces occurs through a substrate-mediated process of adsorbate-metal bond photoexcitation, although crucial underlying phenomena controlling the efficiency of this process are still poorly understood. In this work, substrate-mediated photochemistry on metal surfaces was analyzed by combining dynamical models associated with the metal substrate photoexcitation and electron-mediated bond-activation processes. An extended version of two-temperature model was utilized to treat temporal evolution of photoexcited charge carriers in the metal substrate. The electron-induced adsorbate dynamics on the metal surface was modeled using a nonadiabatic, first-principles based inelastic electron scattering model. Photoactivation of three well studied reactions on Pt(111) surfaces, CO and NO desorption and O diffusion, were chosen as model systems. Through our approach, we addressed unresolved issues associated with adsorbate specific reaction time scales and wavelength and temperature-dependent behavior. The results suggest that activating adsorbate-metal bonds with targeted photon wavelengths and at optimal system temperatures could provide an approach to control selectivity in photon-driven reactions on metal surfaces.