Photoactivity of S-doped nanoporous activated carbons: A new perspective for harvesting solar energy on carbon-based semiconductors

Photoactivity of S-doped nanoporous carbons was tested using photocurrent generation, cyclic voltammetry and photodegradation of methylene blue (MB) under artificial solar irradiation. The results were compared to those obtained on unmodified carbons and on commercial TiO2. A significant generation of photocurrent at visible and NIR radiation from 400 to 1200 nm was found. An exposure to ambient light has a strong effect on an open circuit potential indicating the strong activity of S-doped carbons in oxidation reactions. The activity in the process of MB degradation was about 2.2 and 1.9 higher than that obtained on a commercial TiO2. The extent of photoactivity depends both on the composition of the activated carbon and on the sulfur content. The results suggest that incorporation of sulfur decreases the energy band gap in activated carbon. (C) 2012 Elsevier B.V. All rights reserved.