Title

Sulfur doping effects on the electronic and geometric structures of graphitic carbon nitride photocatalyst: insights from first principles

Authors

Authors

S. Stolbov;S. Zuluaga

Comments

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Abbreviated Journal Title

J. Phys.-Condes. Matter

Keywords

TOTAL-ENERGY CALCULATIONS; VISIBLE-LIGHT; WATER; APPROXIMATION; GAS; Physics, Condensed Matter

Abstract

We present here results of our first-principles studies of the sulfur doping effects on the electronic and geometric structures of graphitic carbon nitride (g-C3N4). Using the ab initio thermodynamics approach combined with some kinetic analysis, we reveal the favorable S-doping configurations. By analyzing the valence charge densities of the doped and undoped systems, we find that sulfur partially donates its p(x)- and p(y)-electrons to the system with some back donation to the S p(z)-states. To obtain an accurate description of the excited electronic states, we calculate the electronic structure of the systems using the GW method. The band gap width calculated for g-C3N4 is found to be equal to 2.7 eV, which is in agreement with experiment. We find the S doping causes a significant narrowing of the gap. Furthermore, the electronic states just above the gap become occupied upon doping, making the material a conductor. Analysis of the projected local density of states provides an insight into the mechanism underlying such changes in the electronic structure of g-C3N4 upon S doping. Based on our results, we propose a possible explanation for the S-doping effect on the photocatalytic properties of g-C3N4 observed in experiments.

Journal Title

Journal of Physics-Condensed Matter

Volume

25

Issue/Number

8

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

7

WOS Identifier

WOS:000314780400018

ISSN

0953-8984

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