The addition of Li to Ti02-based anatase enhances considerably the activity of this type of catalyst. Evidence is presented here for the influence of ion doping on the observed charge-transfer processes on the catalyst surface. It shows that Li doping promotes conduction band electron transfer. This effect is likely to contribute to the observed enhancement in hydrogen generation and oxygen photoadsorption with increased Li content. Electron microscopy and other structure studies show that Li diffuses into the anatase bulk, altering the structure of this material. Implications of such alterations in water photocleavage under UV light are discussed. Displacement of the conduction band to more positive values takes place upon Li doping of Ti02 samples.
A study has been made of the irradiation of red mercury(@ sulphide electrodes in water, acetonitrile, pyridine and methanol containing dissolved tetra-alkylammonium salts. Photocurrents were found to be due to solvent oxidation, iodide oxidation and lattice decomposition, but which of these processes actually operates is determined by the individual solvent, solvation of the iodide ion and adsorption of the tetra-alkylammonium cation on the semiconductor surface. The length of the alkyl chain of the substituted ammonium ion was critical.Instability of the sulphide resulted from adsorption of tetra-alkylammonium cations in methanol and acetonitrile. In the case of pyridine, cation adsorption was not significant, but the presence of iodide induced a negative shift of the sulphide band edges.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.