Enhanced catalytic activity of potassium-doped graphitic carbon nitride induced by lower valence position

The potassium doped graphitic carbon nitride (K-C3N4) photocatalysts were prepared via thermal polymerization of dicyandiamide and Kiln atmosphere. The valence band (VB) position of g-C3N4 was decreased via potassium doping, resulting in enhanced separation and immigration of photogenerated carriers under visible light. The optimum K-C3N4 exhibited obviously enhanced photocatalytic activities for phenol and MB degradation, which were about 3.3 and 5.8 times as high as those of bulk g-C3N4, respectively. The photocatalytic activity of K-C3N4 decreased with excessive KI mass fraction in the precursor due to the incomplete polymerization of g-C3N4. (C) 2014 Elsevier B.V. All rights reserved.