In situ fabrication of CdMoO4/g-C3N4 composites with improved charge separation and photocatalytic activity under visible light irradiation

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.