Enhancement of Photocatalytic Activity under Visible Light Irradiation via the AgI@TCNQ Core-Shell Structure

Abstract

In this paper, a AgI@TCNQ photocatalyst with a core-shell structure was reported. A two-dimensional TCNQ (7,7,8,8-Tetracyanoquinodimethane) nanosheet, with a π-π conjugate structure, was used as a shell layer to realize the flexible coating on the surface of AgI nanoparticles. These special core-shell structure composites solve the key problems of the small interface of the bulk composites and the lesser charge transfer paths, which could accelerate the migration of photogenerated carriers. Thus, the AgI@TCNQ photocatalysts showed the better photodegradation performance for the methylene blue (MB) solution, and the degradation rate of AgI@TCNQ (1 wt.%) composite was 1.8 times than AgI under irradiation. The reactive species trapping experiments demonstrated that ·O2−, h+, and ·OH all participated in the MB degradation process. The photocatalytic mechanism of AgI@TCNQ composites could be rationally explained by considering the Z-scheme structure, resulting in a higher redox potential and more efficient separation of charge carriers. At the same time, the unique core-shell structure provides a larger contact area, expands the charge transport channel, and increases the surface active sites, which are beneficial for improving photocatalytic performance.

Preparation of g-C3N4/TCNQ Composite and Photocatalytic Degradation of Pefloxacin

“…Xie’s group [ 31 ] successfully synthesized AgI @ TCNQ composites for the photocatalytic degradation of methylene blue (MB) and found that the degradation rate of the composites was 1.8 times higher than that of AgI.…”

Synthesis of WO₃/AgI photocatalysts applying for degradation of antibiotics in water

“…The obtained XRD pattern of the WO3 indica t ed that characteristic diffraction peaks of monoclinic WO3 observed at 23.1 (002); 23.7 (020): 24.4 (200) and 34,1° (202) (JCPDS: 43-1035) [12-14]. The XRD diffractogram of the synthesized AgI displayed three overt diffractio n peaks at 23.6; 39.1 and 46.4 o , which respectively pertained to (002), (110) and (112) planes of the typical hexagonal AgI[15][16][17]. For WO3/AgI composites, the XRD diffractogram of the synthesized samples exhibited wide triplet diffraction peaks at 2θ in range of 22.5 to 25.…”