AVS 59th Annual International Symposium and Exhibition
    Energy Frontiers Focus Topic Friday Sessions
       Session EN+SS-FrM

Paper EN+SS-FrM7
Doping Effects on the Electronic Structure of Graphitic C3N4 Photocatalysts: Insights from First Principles

Friday, November 2, 2012, 10:20 am, Room 15

Session: Photocatalysis and Solar Fuels
Presenter: S. Zuluaga, University of Central Florida
Authors: S. Zuluaga, University of Central Florida
S. Stolbov, University of Central Florida
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Band gap engineering and facilitating charge separation in the graphitic C3N4 semiconductors are promising means for improving the photocatalytic activity of these materials. A number of experiments suggest that doping of C3N4 is an efficient way to increase the rate of hydrogen production from water using this photocatalyst. In this work we apply a first principles computational approach to reveal the main factors controlling the S and P doping effects on the properties of C3N4. Our density-functional-theory-based calculations show that these dopants are bound to the edges of the triazine elements rather than substituting N or C. Valence charge density analysis provides detailed description of the charge transfer upon doping. We show, for example, that S does not work as an anion in these materials: it does not accept, but donates electronic charge to the C – N system. Using the GW method we calculate with high accuracy the electronic structure, including the band gap, of the pristine and doped C3N4. We show that sufficiently large S doping make the system a conductor. The obtained results shed light on how doping affect the catalytic properties of C3N4.