Boosting the photocatalytic performance of Ag2CO3 crystals in phenol degradation via coupling with trace N-CQDs

A series of N-CQDs/Ag2CO3 composite crystals (where N-CQDs = Nitrogen doped carbon quantum dots) were prepared by adding different volumes of a solution of N-CQDs during Ag2CO3 crystal growth. Under irradiation from a 350-W Xe lamp light (with optical filter, lambda >= 420 nm), the performance of N-CQDs/Ag2CO3 in photocatalytic degradation of phenol was evaluated. The as-prepared samples were analyzed by XRD, SEM, TEM, BET, element mapping, UV-vis DRS, FT-IR, XPS, transient photocurrent response and EIS testing. The results showed that after coupling with trace amounts of N-CQDs, both the photocatalytic activity and stability of Ag2CO3 were greatly boosted. The addition of N-CQDs solution influenced the crystallization of Ag2CO3, resulting in a distinct decrease in Ag2CO3 crystal size and an obvious increase in surface area. Moreover, the charge transfer resistance was greatly reduced, and the separation efficiency of photogenerated electrons and holes was strongly promoted. The presence of NCQDs on the surface of the catalysts facilitates the transfer of photogenerated electrons, slowing the photocorrosion rate of Ag2CO3, and then resulting in higher stability than bare Ag2CO3 in degradation. The synergistic effect of the improvement of morphology and charge transfer rate thus accounted for the superior photocatalytic performance of N-CQDs/Ag2CO3. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.