Qiong Liu

Novel Z-scheme visible-light-driven Ag3PO4/Ag/SiC photocatalysts with enhanced photocatalytic activity

Visible-light-driven Ag3PO4/Ag/SiC photocatalysts with different weight fractions of SiC were synthesized via an in situ precipitation method and characterized by X-ray diffraction (XRD) and UV-vis diffuse reflectance spectroscopy (DRS). Under visible light irradiation (>420 nm), the Ag3PO4/Ag/SiC photocatalysts degraded methyl orange (MO) and phenol efficiently and displayed much higher photocatalytic activity than that of pure Ag3PO4/Ag or SiC/Ag, and the Ag3PO4/Ag/SiC hybrid photocatalyst with 10% of SiC exhibited the highest photocatalytic activity. The quenching effects of different scavengers demonstrated that reactive h+ and O2˙− played the major role in the MO degradation. It was elucidated that the excellent photocatalytic activity of Ag3PO4/Ag/SiC for the degradation of MO under visible light (λ > 420 nm) can be ascribed to the efficient separation of photogenerated electrons and holes through the Z-scheme system composed of Ag3PO4, Ag and SiC, in which the Ag nanoparticles acted as the charge transmission-bridge. The Ag3PO4/Ag/SiC hybrid maintained good photocatalytic activity after 10 times of cycle experiments.

A one-step process for preparing a phenyl-modified g-C3N4 green phosphor with a high quantum yield

Herein a simple one-step process for preparing a g-C3N4-based green phosphor was presented, which just involved thermal polymerization of a single precursor, 2,4-diamino-6-phenyl-1,3,5-triazine, under an atmosphere of argon, to prepare phenyl-modified g-C3N4. The effects of the annealing temperature and time on the crystalline structure, chemical composition, morphology, optical absorption properties, and photoluminescence emission behavior of the obtained samples were investigated systematically. It was found that the phenyl-modified g-C3N4 prepared at 400 °C for 40 min exhibits strong green emission with a quantum yield of as high as 38.08%, comparable to those of the g-C3N4 nanoparticles and quantum dots obtained from the multi-step preparation and post-treatment processes. The emission spectrum of the phenyl-modified g-C3N4 sample can be fitted into four peaks centered at around 465, 490, 520 and 545 nm, suggesting that the phenyl-modified g-C3N4 phosphor possesses multi-fluorophores or luminescent species. The introduction of the phenyl groups leads to the decrease in band gap and thus the red shift in emission as compared with pristine g-C3N4. The simple preparation process along with high quantum yield make this phenyl-modified g-C3N4 green phosphor show great potential in practical applications.