Plasmon-induced long-lived hot electrons in degenerately doped molybdenum oxides for visible-light-driven photochemical reactions

Plasmon-induced hot electrons offer unique advantages in solar-light-driven chemical reactions. Noble metal nanostructures have been the most studied plasmonic materials, but the hot electron lifetime is extremely short. Here, we have discovered extraordinarily long-lived hot electrons in degenerately doped molybdenum oxides with surface plasmon resonance in the visible and near-infrared region. Their lifetime is nanosecond-scale, which is enhanced by 4 orders of magnitude compared to their noble metal counterparts. Such a property is ascribed to the quasi-metallic feature of molybdenum oxides driven by hydrogen dopant-induced bandgap trap states, in which the electron-phonon scattering is dominant over the ultrafast electron-electron scattering in the decay dynamics of hot electrons. The plasmonic dye oxidation and hydrogen evolution are explored without the coupling of semiconductors, providing a viable way towards expanding the candidates for direct plasmonic photocatalysis.