Highly photoactive anatase nanoparticles obtained using trifluoroacetic acid as an electron scavenger and morphological control agent

Abstract

Fluorine species adsorbed on the surface of TiO₂ anatase nanoparticles improve their photocatalytic performance by reducing the recombination rate of photogenerated electrons and holes. Trifluoroacetic acid (TFAA) has been recently proposed as a promising harmless substitute for hydrofluoric acid (HF) in preparing fluorine-modified anatase with good scavenger properties. However the photocatalytic performance of the TiO₂ nanoparticles also depends on their specific morphology, by which the number and type of crystal facets, which remain exposed, are determined. A comprehensive study is presented in this contribution which for the first time describes the role of TFAA in stabilizing the highly photoactive {001} TiO₂ facets. Furthermore, by reducing the amount of water incorporated into the reaction medium, a simple one-step synthesis method is also proposed that allows the preparation of TFAA-modified anatase nanoparticles with specific morphology and selected stabilized facets, eventually yielding a semiconductor material with excellent photocatalytic properties.