2D Plasmonic Photocatalyst Enables Highly Efficient Hot-Electron-Mediated Surface Reactions under Red Light Irradiation

Plasmonic photocatalysis is promising for solar-driven chemical transformations under mild conditions; however, conventional materials like aluminum, copper, silver, and gold are resonant at short wavelengths, limiting their use in the red to near-infrared sunlight spectrum. In this study, we have developed a class of antenna-reactor (AR) photocatalyst based on two-dimensional (2D) plasmonic materials, Ti₃C₂T_<i>x</i>, also known as MXenes. A Ru-loaded Ti₃C₂T_<i>x</i> plasmonic photocatalyst achieves a turnover frequency of approximately 2 s^-1 and energy efficiency of 10% for hydrogen production under 660 nm light excitation, being 2-3 orders of magnitude superior to the performance achieved in thermocatalysis. This 2D plasmonic antenna demonstrates superiority over the benchmark CuRu surface-alloy AR structure in hot-electron-driven processes under red light excitation. Kinetic studies suggest that the rate-determining step in both photo- and thermocatalysis is nitrogen's associative desorption. Hot electrons enhance activity by promoting the removal of adsorbed nitrogenous species.