ZnO-embedded S-doped g-C 3 N 4 heterojunction: mediator-free Z-scheme mechanism for enhanced charge separation and photocatalytic degradation.

The design of UV-visible light active photocatalysts for organic pollutant removal is a challenging task. Herein, we have developed an LED light active ZnO-embedded S-doped g-C 3 N 4 (SCN) heterojunction by a facile sol-gel assisted calcination method. The heterojunction between ZnO and SCN nanoparticles generates a Z-scheme photocatalyst, which helps to separate the photo-induced charge carriers in the opposite direction, and is beneficial for more visible light absorption for photocatalytic dye degradation. The composite heterojunction shows better photocatalytic redox in comparison with pristine nanomaterials. The enhanced degradation efficiency is attributed to the high production rate of ˙OH (hydroxyl) radicals during the photocatalysis process, which is analyzed by the TA test and elemental trapping experiment. Hence, we hope that this Z-scheme heterojunction provides a new way to develop UV-visible light active photocatalysts for environmental remediation applications.