Soft-chemical synthesis of nanometer-thick carbon-coated titania: effect of carbon-coating on the photocatalytic activity of TiO2.

Nanometer-thick carbon layer can be successfully coated on titanium oxide via a novel soft-chemical route involving a dehydration process of adsorbed carbohydrate molecules assisted by sulfuric acid. According to powder X-ray diffraction and Ti K-edge X-ray absorption spectroscopic analysis, carbon-coating leads to no significant modification in the anatase-type atomic arrangement of titanium oxide. Transmission electron microscopy, elemental CHNS analysis, and micro-Raman spectroscopy clearly demonstrated that disordered graphitic carbon layer is uniformly coated on the surface of titanium oxide. Of special importance is that the carbon-coating can improve an ability of titanium oxide to remove organic pollutant. On the basis of the experimental findings, we are able to conclude that the present low temperature dehydration method provides a less energy-consuming route not only to the carbon-coating of titanium oxide but also to the improvement of the photocatalytic activity of semiconducting metal oxide.