Fast electron transfer and enhanced visible light photocatalytic activity by using poly-o-phenylenediamine modified AgCl/g-C3N4 nanosheets

• Published in: Chinese journal of catalysis 2019-01, Vol.40 (1), p.80-94
• Main Authors: Sun, Linlin, Liu, Chongyang, Li, Jinze, Zhou, Yaju, Wang, Huiqin, Huo, Pengwei, Ma, Changchang, Yan, Yongsheng
• Format: Article
• Language: English
• Subjects: AgCl; g-C3N4 nanosheets; Photocatalytic; Poly-o-phenylenediamine; Visible light irradiation
• ISSN: 1872-2067; 1872-2067
• DOI: 10.1016/S1872-2067(18)63172-9

Exfoliation of bulk graphitic carbon nitride (g-C3N4) into two-dimensional (2D) nanosheets is one of the effective strategies to improve its photocatalytic properties so that the 2D g-C3N4 nanosheets (CN) have larger specific surface areas and more reaction sites. In addition, poly-o-phenylenediamine (PoPD) can improve the electrical conductivity and photocatalytic activity of semiconductor materials. Here, the novel efficient composite PoPD/AgCl/g-C3N4 nanosheets was first synthesized by a precipitation reaction and the photoinitiated polymerization approach. The obtained photocatalysts have larger specific surface areas and could achieve better visible-light response. However, silver chloride (AgCl) is susceptible to agglomeration and photocorrosion. The PoPD/AgCl/CN composite exhibits an extremely high photocurrent density, which is three times that of CN. Obviously enhanced photocatalytic activities of PoPD/AgCl/g-C3N4 are revealed through the photodegradation of tetracycline. The stability of PoPD/AgCl/CN is demonstrated based on four cycles of experiments that reveal that the degradation rate only decreases slightly. Furthermore, •O2− and h+ are the main active species, which are confirmed through a trapping experiment and ESR spin-trap technique. Therefore, the prepared PoPD/AgCl/CN can be considered as a stable photocatalyst, in which PoPD is added as a charge carrier and acts a photosensitive protective layer on the surface of the AgCl particles. This provides a new technology for preparing highly stable composite photocatalysts that can effectively deal with environmental issues. The degradation efficiency of tetracycline over PoPD/AgCl/CN composites synthesized by precipitation reaction and photoinitiated polymerization approach was three times higher than that over pure CN; •O2− and h+ are the main reactive species in the case of PoPD/AgCl/CN.