Enhancement of mineralization ability of C3N4via a lower valence position by a tetracyanoquinodimethane organic semiconductor

7,7,8,8-Tetracyanoquinodimethane-g-C3N4 (TCNQ-g-C3N4) organic composite photocatalysts were prepared by a liquid ultrasonic route in water. The phenol mineralization ability of a TCNQ-g-C3N4 composite was dramatically enhanced via decreasing the valence position of the composite by adjusting the mass fraction of TCNQ. The transition of photogenerated electrons from the valence band of C3N4 to the LUMO of TCNQ was promoted by the charge transfer between C3N4 donor and TCNQ acceptor. The separation and immigration efficiency of photoinduced charge carriers was greatly enhanced and the catalytic activity of the TCNQ-g-C3N4 composite was increased about 8.4 times for phenol degradation.