Photocatalytic oxidation of 2-ethoxyethanol in a water suspension of titanium dioxide

The influence of ferrous ions on the efficiency of aqueous photocatalytic oxidation of 2‐ethoxy ethanol

“…The promotion of the OH-radical was less effective in oxidation of ethylene glycol derivatives [16,17]. The increasing PCO efficiency for 2-EE with the addition of ferrous ions in small, below 0.09 mM, concentrations may then be explained by the partial occupation of adsorption sites with Fe 2+ -ions, overpowered, however, with the electron scavenging by iron ions, extending the lifetime and thus the oxidation performance of the positively charged holes.…”

Trap-State Distributions and Carrier Transport in Pure and Mixed-Phase TiO2: Influence of Contacting Solvent and Interphasial Electron Transfer

“…The similar intensity of P25 PL in the presence of neat ACN and dilute EtOH in ACN (Figure S3, Supporting Information) strongly suggests that EtOH is preferentially adsorbed on the surface of P25. Ethanol and related molecules are well-known to adsorb at oxygen vacancies of TiO 2 . , Thus, in addition to hole scavenging, EtOH and by inference also MPN and DMF might be capable of passivating the red emitting traps of anatase by adsorbing at the associated defect sites, resulting in P25-like PL. To understand why the same three solvents (EtOH, MPN, and DMF), which result in the conversion of anatase PL from “anatase-like” to “P25-like”, also result in the largest PL intensity of P25, we must consider the role of nonradiative recombination as well.…”

Heterogeneous photocatalysis

“…Hydroxyl radicals have been observed upon irradiation of aqueous suspensions of Ti02 in the presence of spin traps such as 5,5-dimethyl-1-pyrroline N-oxide. 63 Both electron-spin resonance detection of a spintrapped OH adduct116 and indirect kinetic evidence116 point to the formation of the hydroxy radical on illuminated Ti02 in contact with water. Spectra of other transient intermediates formed from organic or inorganic adsorbates on the surface of the illuminated semiconductor after hole trapping can be detected by diffuse reflectance spectroscopy.117 On irradiated Ti02 powders in contact with strongly adsorbed substrates, however, time-resolved diffuse reflectance spectroscopy was used to assign the observed transients as single electron oxidized intermediates (formed by hole trapping) rather than to hydroxy radical adducts.117* Note that a surface-bound OH radical is chemically equivalent to a surface-trapped hole and that many investigators use these terms interchangeably.…”