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, Ti3C2Tx, also known as MXenes. A Ru-loaded Ti3C2Tx 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.