Boosting Gas-Phase TiO 2 Photocatalysis with Weak Electric Field Strengths of Volt/Centimeter
Résumé
Among the semiconductor nanomaterials, titanium dioxide is at the forefront of heterogeneous photocatalysis, but its catalytic activity greatly suffers from the loss of photoexcited charge carriers through deleterious recombination processes. Here, we investigate the impact of an external electric field applied to conventional P25 TiO 2 nanopowder with or without Au nanoparticles to circumvent this issue. The study of two redox reactions in gas phase, water splitting and toluene degradation, reveals an enhancement of the photocatalytic activity with rather modest electric fields of a few V/cm only. Such an improvement arises from the electric field-induced quenching of the green emission in anatase, allowing the photoexcited charge carriers to be transferred to the adsorbed reactants instead of pointless radiative recombinations. Applying an external electric field across a trap-rich metal oxide material, such as TiO 2 , which, when impregnated with Au nanoparticles, leads respectively to a twelve-fold and six-fold enhancements in the production of hydrogen and the oxidation of toluene for an electric field of 8 V/cm, without any electrolysis, is a simple and elegant strategy to meet higher photocatalytic efficiencies.
Domaines
Chimie| Origine | Fichiers produits par l'(les) auteur(s) |
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