Routes to visible light active C-doped TiO2 photocatalysts using carbon atoms from the Ti precursors

• C-doped titanate TiO2 nanoparticles are prepared using non-standard calcinations.
• C atoms from the sol–gel precursor can be incorporated into the TiO2 lattice.
• Low temperature calcinations lead to poorly crystalline C-TiO2.
• High temperature He treatments lead to C(s) as well as C-TiO2.
• Combinations of low temperature calcinations and high temperature He treatments lead to useful photocatalysts.

In this work, different thermal treatments of titanium isopropoxide-derived photo-catalyst precursors, designed with the purpose of generating C-doped TiO2 photo-catalysts using carbon atoms present in the TiOx gel precursors as dopants, are presented. Specifically, these look at varying the standard calcination techniques using heat treatments in He (rather than calcination in air) and lower temperature calcinations (200 °C rather than 500 °C). The formed materials are characterised using N2 physisorption, XRD, UV–Visible spectroscopy and XPS and their activities in promoting the oxidation of 4-chlorophenol under visible-light-only conditions were analysed. The nature of carbon remaining on the (or in the) material is discussed found to be both surface graphitic carbon and carbon present in anionic dopant positions. The different contributions of each type of carbon to the catalytic photo-activity under visible light are discussed.

Figure optionsDownload as PowerPoint slide