Surface-Modified TiO Photocatalysts Prepared by a Photosynthetic Route: Mechanism, Enhancement, and Limits.

Surface-modified TiO photocatalysts were synthesized by a photosynthetic route involving visible-light-induced (λ>455 nm) activation of benzene and toluene at the surface of TiO leading to the formation of carbonaceous polymeric deposits. IR spectroscopic and photoelectrochemical experiments showed that the mechanism of the photosynthetic reactions involves intra-bandgap surface states at TiO related to surface OH groups interacting with adsorbed aromatic molecules. The photosynthesized surface-modified TiO materials exhibited enhanced activity, relative to pristine TiO , in photocatalytic degradation (and complete mineralization) of 4-chlorophenol.

Lewis base mediated efficient synthesis and solvation-like host-guest chemistry of covalent organic framework-1.

N-Lewis base mediated room temperature synthesis of covalent organic frameworks (COFs) starting from a solution of building blocks instead of partially soluble building blocks was developed. This protocol shifts COF synthetic chemistry from sealed tubes to open beakers. Non-conventional inclusion compounds of COF-1 were obtained by vapor phase infiltration of ferrocene and azobenzene, and solvation like effects were established.

Enhanced performance of surface-modified TiO2 photocatalysts prepared via a visible-light photosynthetic route.

Benzene can be activated by visible light (λ > 455 nm) in the presence of TiO(2), which leads to formation of carbonaceous polymeric deposits on the titania surface. These photosynthesized surface-modified materials exhibit enhanced photoactivity in degradation of phenolic compounds, particularly under visible light irradiation.

Visible-light photooxidation of water to oxygen at hybrid TiO2 -polyheptazine photoanodes with photodeposited Co-Pi (CoO(x)) cocatalyst.

A cobalt oxide-based oxygen-evolving cocatalyst (Co-Pi) is photodeposited by visible-light irradiation onto nanocrystalline TiO(2)-polyheptazine (TiO(2)-PH) hybrid photoelectrodes in a phosphate buffer. The Co-Pi cocatalyst couples effectively to photoholes generated in the surface polyheptazine layer of the TiO(2)-PH photoanode, as evidenced by complete photooxidation of water to oxygen under visible-light (λ>420 nm) irradiation at moderate bias potentials. In addition, the presence of the cocatalyst also reduces significantly the recombination of photogenerated charges, particularly at low bias potentials, which is ascribed to better photooxidation kinetics resulting in lower accumulation of holes.

Visible-light photocurrent response of TiO2-polyheptazine hybrids: evidence for interfacial charge-transfer absorption.

We investigated photoelectrodes based on TiO(2)-polyheptazine hybrid materials. Since both TiO(2) and polyheptazine are extremely chemically stable, these materials are highly promising candidates for fabrication of photoanodes for water photooxidation. The properties of the hybrids were experimentally determined by a careful analysis of optical absorption spectra, luminescence properties and photoelectrochemical measurements, and corroborated by quantum chemical calculations.