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

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 (center dot O-2(-)) 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. (C) 2020, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.