Abstract: To further improve the charge separation and photocatalytic activities of g-C₃N₄ and CdMoO₄ under visible light irradiation, CdMoO₄/g-C₃N₄ composites were rationally synthesized by a facile precipitation-calcination procedure. The crystal phases, morphologies, chemical compositions, textural structures, and optical properties of the as-prepared composites were characterized by the corresponding analytical techniques. The photocatalytic activities toward degradation of rhodamine B solution were evaluated under visible light irradiation. The results revealed that integrating CdMoO₄ with g-C₃N₄ could remarkably improve the charge separation and photocatalytic activity, compared with those of pristine g-C₃N₄ and CdMoO₄. This would be because the CdMoO₄/g-C₃N₄ composites could facilitate the transfer and separation of the photoexcited electron-hole pairs, which was confirmed by electrochemical impedance spectroscopy, transient photocurrent responses, and photoluminescence measurements. Moreover, active species trapping experiments demonstrated that holes (h⁺) and superoxide radicals (·O₂^-) were the main active species during the photocatalytic reaction. A possible photocatalytic mechanism was proposed on the basis of the energy band structures determined by Mott-Schottky tests. This work would provide further insights into the rational fabrication of composites for organic contaminant removal.

Key words: CdMoO₄/g-C₃N₄ composite, Heterojunction, Charge separation, Visible light, Photocatalytic activity