ALTHOUGH the possibility of water photolysis has been investigated by many workers, a useful method has only now been developed. Because water is transparent to visible light it cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm (ref. 1).

Electrochemical Photolysis of Water at a Semiconductor Electrode

Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Films and powders of TiO 2- x N x have revealed an improvement over titanium dioxide (TiO 2 ) under visible light (wavelength 2 has proven to be indispensable for band-gap narrowing and photocatalytic activity, as assessed by first-principles calculations and x-ray photoemission spectroscopy.

/pdf/visible-light-photocatalysis-in-nitrogen-doped-titanium-np6nklr9gh.pdf

Visible-Light Photocatalysis in Nitrogen-Doped Titanium Oxides

Titanium Dioxide Nanomaterials: Synthesis, Properties, Modifications, and Applications

The surface science of titanium dioxide

We present the evidence for the surface density of states (SDOS) of the hydroxylated and reduced rutile TiO2 (110) single crystal different from the bulk electronic property by tunneling spectroscopy using scanning tunneling microscopy technique (STM/TS). The surface band gap energy (SEg) was 1.6 eV as the tunneling‐active free states. This experimentally obtained SEg (1.6 eV) was quite different from the bulk band gap energy (3.05 eV). The chemisorbed OH− on the Ti3+ –O vacancy state is located 1.35 eV below the EF . The observed tunneling current rectification originates in the surface electronic structure, band bending and surface coordination property. It became clear that the photo‐oxidation of the chemisorbed OH− by photogenerated holes was energetically feasible through the study of SDOS using the STM/TS. Phenol molecules were adsorbed onto the hydroxylated TiO2 surface. The image of the phenol molecule was measured at a tip bias of +443 mV which is within the surface band gap and slightly larger than the vibration energy of phenol ring. The electron density of the phenol ring was apparent in the STM picture.

Surface density of states of TiO2(110) single crystal and adsorbed molecular observation by scanning tunneling microscopy and tunneling spectroscopy

Electrochemical oxidation of Mn 2+ with and without the presence of Bi 3+ was studied using voltammetric and in situ spectro-electrochemical techniques at boron-doped diamond (BDD) electrodes in 1.0 M HClO 4 . Electrochemical oxidation of only Mn 2+ resulted in the formation of mostly MnO 2 with MnO - 4 produced as a minor product. The MnO 2 film formed on the electrode surface, which is an inevitable part of Mn 2+ oxidation, shows a blocking effect on the formation of MnO - 4, and reduces the overall current efficiency of MnO4 production. Higher Mn 2+ concentrations result in less MnO - 4 production due to the formation of more MnO 2 . The addition of Bi 3+ increased the current efficiency of MnO4 production. The Bi 3+ is oxidized to Bi(V), which acts as an electrocatalyst in MnO - 4 production. The Bi(V) oxidizes MnO 2 , formed on the electrode surface, to MnO - 4. This increases the production of MnO4 by removing the blocking film to provide an active electrode (bare BDD) surface, which is available for further Mn 2+ oxidation.

Electrochemical Oxidation of Mn2 + on Boron-Doped Diamond Electrodes with Bi3 + Used as an Electron Transfer Mediator

The right way

Electrochemical reduction of carbon dioxide on hydrogen-storing materials: Part 4. Electrochemical behavior of the Pd electrode in aqueous and nonaqueous electrolyte

Akira Fujishima

Papers

Surface density of states of TiO2(110) single crystal and adsorbed molecular observation by scanning tunneling microscopy and tunneling spectroscopy

Electrochemical Oxidation of Mn2 + on Boron-Doped Diamond Electrodes with Bi3 + Used as an Electron Transfer Mediator

The right way

Electrochemical reduction of carbon dioxide on hydrogen-storing materials: Part 4. Electrochemical behavior of the Pd electrode in aqueous and nonaqueous electrolyte

Electrochemical reduction of carbon dioxide on hydrogen-storing materials.: Part II. Copper-modified palladium electrode