Enhancement of visible light photocatalytic activities via porous structure of g-C3N4

The series porous graphitic carbon nitride (pg-C3N4) materials have been prepared by pyrolysis of dicyandiamide in air using urea as bubble template. The surface area of as-prepared pg-C3N4 was increased from 5.4 to 60 m(2) g(-1) by increasing the mass ratio of urea/dicyandiamide and calcination temperature. We have found that thus-produced nanostructures can display efficient photocatalytic performance for the photodegradation of methylene blue (MB) and phenol pollutant when energized with visible light. The photocurrent and photocatalytic activities of as-synthesized pg-C3N4 were increased with the higher proportion of urea and calcination temperature under visible light irradiation. Compared with the bulk g-C3N4, the optimum photocatalytic activity of our synthesized pg-C3N4 displays a significant enhancement by a factor of 2.1 and 2.8 for MB and phenol, respectively. The separation and migration efficiency of photogenerated electron-hole pairs were improved by the porous structure, which resulted in the enhancement of photocatalytic performances. (C) 2013 Elsevier B.V. All rights reserved.