Hydrated electrons are important in radiation chemistry and charge transfer reactions, with applications that include chemical damage of DNA, catalysis, and signaling. Conventionally, hydrated electrons are produced by pulsed radiolysis, sonolysis, two-ultraviolet-photon laser excitation of liquid water, or photodetachment of suitable electron donors. Here we report a method for the generation of hydrated electrons via single-visible-photon excitation of localized surface plasmon resonances (LSPRs) of supported sub-3 nm copper nanoparticles in contact with water. Only excitations at the LSPR maximum resulted in the formation of hydrated electrons, suggesting that plasmon excitation plays a crucial role in promoting electron transfer from the nanoparticle into the solution. The reactivity of the hydrated electrons was confirmed via proton reduction and concomitant H-2 evolution in the presence of a Ru/TiO2 catalyst.

We have successfully investigated the simultaneous injection of hot electrons and holes upon excitation of gold localized surface plasmon resonance (LSPR). The studies were performed on all-solid-state plasmonic system composed of titanium dioxide (TiO2)/poly(3,4-ethylenedioxythiophene) :poly(styrenesulfonic acid) (PEDOT:PSS) p-n junctions with gold nanoparticles (Au NPs). The study revealed that both charge carriers are transferred within 200 fs to the respective charge acceptors, exhibiting a free carrier transport behavior. We also confirmed that the transfer of charge carriers are accompanied by change in the initial relaxation dynamics of Au NPs.

Light-driven proton-coupled electron transfer (PCET) reactions on nanoplasmonics would bring temporal control of their reactive pathways, in particular, prolong their charge separation state. Using a silver nano-hybrid plasmonic structure, we observed that optical excitation of Ag-localized surface plasmon instigated electron injection into TiO2 conduction band and oxidation of isopropanol alcoholic functionality. Femtosecond transient infrared absorption studies show that electron transfer from Ag to TiO2 occurs in ca. 650 fs, while IPA molecules near the Ag surface undergo an ultrafast bidirectional PCET step within 400 fs. Our work demonstrates that ultrafast PCET reaction plays a determinant role in prolonging charge separation state, providing an innovative strategy for visible-light photocatalysis with plasmonic nanostructures.

The work presents a full physicochemical characterization of sulfonated cellulose beads prepared from Cladophora nanocellulose intended for use in biological systems. 2,3-Dialdehyde cellulose (DAC) beads were sulfonated, and transformation of up to 50% of the aldehyde groups was achieved, resulting in highly charged and porous materials compared to the compact surface of the DAC beads. The porosity could be tailored by adjusting the degree of sulfonation, and a subsequent reduction of the aldehyde groups to hydroxyl groups maintained the bead structure without considerable alteration of the surface properties. The thermal stability of the DAC beads was significantly increased with the sulfonation and reduction reactions. Raman spectroscopy also showed to be a useful technique for the characterization of sulfonated cellulose materials.

The efficient conversion of light energy into chemical energy is key for sustainable human development. Several photocatalytic systems based on photovoltaic electrolysis have been used to produce hydrogen via water reduction. However, in such devices, light harvesting and proton reduction are carried separately, showing quantum efficiency of about 10–12%. Here, we report a nano-hybrid photocatalytic assembly that enables concomitant reductive hydrogen production and pollutant oxidation with solar-to-fuel efficiencies up to 20%. The modular architecture of this plasmonic material allows the fine-tuning of its photocatalytic properties by simple manipulation of a reduced number of basic components.

In this work, we report for the first time a unique configuration of N-doped and Cu-doped TiO2 bilayer. The activity of TiO2 was improved by combining Cu- and N-doping in a layered thin-film structure. The impact of the stacking order was studied, pointing out how the best arrangement is by far the one with Cu-TiO2 as the top layer. The results reveal a unique and simple way to enhance the photocatalytic response of TiO2 in the visible domain.