Catalytic activity of porous carbon nitride regulated by polyoxometalates under visible light

A series of porous carbon nitrides modified by different polyoxometalates (POMs) were prepared by the ultrasonic method. POMs were assembled on the surface of mpg-C(3)N(4)via electrostatic attraction. The catalyst has visible light degradation activity for phenol (lambda > 420 nm). mpg-C3N4 modified by H4SiW12O40 with a mass ratio of 1 : 5 showed the highest catalytic activity, which was 3.5 times higher than that of mpg-C3N4. As an electron acceptor, polyoxometalate can capture the photoelectron of C3N4, which can promote the separation of photocharge and improve the photocatalytic activity. ESR also confirmed that the superoxide radicals play a major role in degradation. The results show that the charge separation efficiency and catalytic activity can be enhanced by polyacids.