Since the theoretical predictions of Liu and Cohen, carbon nitride
is of current interest due to its unique properties, including low density,
extreme hardness, wear resistance, chemical inertness, biocompatibility
and special optical and electrical properties [1,2]. Especially, polymeric
graphitic carbon nitride (g-C3N4) has been actively studied as a novel
metal-free photocatalyst for photocatalytic energy conversion. This
material has become the focus of considerable research activities
[3–5]. As a photocatalyst, it also exhibits activity for the photodegradation
of organic pollutants in solution [6] or in air [7] under
visible light irradiation. Since the g-C3N4 photocatalyst possesses high
thermal and chemical stability, it is a valuable and useful material for
applications.