Cobalt-doped graphitic carbon nitride photocatalysts with high activity for hydrogen evolution

Cobalt-doped graphitic carbon nitride (Co-CN) was synthesized by one-step thermal polycondensation using cobalt phthalocyanine (CoPc) and melamine as precursors. The pi-pi interaction between melamine and CoPc promotes cobalt doping into the framework of g-C3N4. The prepared samples were carefully characterized and the results demonstrated that Co-doped graphitic carbon nitride inhibited the crystal growth of graphitic carbon nitride (CN), leading to larger specific surface area (33.1 m(2) g(-1)) and abundant Co-N-x active sites, narrower band gap energy and more efficient separation of photogenerated electrons and holes. 0.46% Co-CN exhibited higher hydrogen evolution rate (28.0 mu mol h(-1)) under visible light irradiation, which is about 3.0 times of that over the pure CN and about 2.2 times of that over cobalt doped CN using CoCl2 center dot 6H(2)O as a cobalt source. This study provides a valuable strategy to modify CN with enhanced photocatalytic performance. (C) 2016 Elsevier B.V. All rights reserved.