Synthesis of oxygen-doped graphitic carbon nitride from thiourea

We have synthesized oxygen-doped graphite-like carbon nitride (g-C$_3$N$_4$) by the thermal treatment of the thiourea at 450–550$^{\circ}$C. With an increase in the annealing temperature, the oxygen concentration in g-C$_3$N$_4$ increases, and the band-gap of the material decreases from 2.64 to 2.47 eV. The semiconductor properties of g-C$_3$N$_4$ doped with oxygen are confirmed by its high photocatalytic activity, determined by decoloration of a Rhodamine B aqueous solution in the presence of g-C$_3$N$_4$ upon irradiation with visible light.