Qunjie Xu

Synthesis and characterization of high efficiency and stable Ag3PO4/TiO2 visible light photocatalyst for the degradation of methylene blue and rhodamine B solutions

A facile and reproducible method for the synthesis of Ag3PO4/TiO2 visible light photocatalyst has been developed to improve the photocatalytic activity and stability of Ag3PO4. The innovation of this method is to in situ deposit Ag3PO4 nanoparticles onto the TiO2 (P25) surface forming a heterostructure. The improved activity of the Ag3PO4/TiO2 heterostructured photocatalyst for the degradation of methylene blue (MB) and rhodamine B (RhB) under visible light irradiation is attributed to the increased surface area and enhanced absorption of MB and RhB. Furthermore, depositing Ag3PO4 onto the surface of TiO2 facilitates electron–hole separation that leads to the elevated photocatalytic activity. The heterostructured Ag3PO4/TiO2 photocatalyst significantly decreases the loading of noble metal Ag from 77 wt% to 47 wt%, thereby significantly reducing the cost for the practical application of Ag3PO4 photocatalyst.

Dual-functional MoS2 sheet-modified CdS branch-like heterostructures with enhanced photostability and photocatalytic activity

CdS/MoS2 heterostructures with a branch-like morphology have been prepared via a one-pot hydrothermal method. The as-prepared CdS/MoS2 heterostructures exhibited enhanced photocatalytic activity and photostability for the degradation of organic dyes. It is believed that the 2D MoS2 sheets supporting CdS form a large number of interfaces, which may significantly increase the separation of electron/hole pairs, thus greatly enhancing the photocatalytic activity. On the other hand, the matched energy bands of the CdS/MoS2 heterostructure also allow hole transfer from CdS to MoS2, thus reducing CdS corrosion.

Self-assembled encapsulation of graphene oxide/Ag@AgCl as a Z-scheme photocatalytic system for pollutant removal

In this study, we have demonstrated a Z-scheme photocatalytic system using Ag@AgCl encapsulated with graphene oxide (GO) (AEGO) composites, where GO and AgCl act as a highly activated photocatalyst, and metallic Ag shuttles photogenerated electrons from the excited GO and AgCl under visible light irradiation. The electron–hole pairs of the low energy level could be recombined in space by metallic Ag as a solid-state electron mediator, the remaining electron–hole pairs of the high energy level are for two photochemical reactions that operate in parallel. The Z-scheme photocatalytic system from the AEGO composite displays a much higher photocatalytic activity than Ag@AgCl-reduced graphene oxide (RGO) with the same quantitative graphene loading (15 wt%) for the degradation of methylene blue (MB). This work may provide a guide to the design of photocatalysts by the use of GO directly.

Enhanced reactive oxygen species on a phosphate modified C3N4/graphene photocatalyst for pollutant degradation

Carbon nitride whose surface is modified with phosphate is hybridized with graphene nanosheets by heating a mixture of melamine and graphene oxide, followed by stirred them in a phosphoric acid solution. The as-prepared phosphate–C3N4/graphene photocatalysts exhibited a higher photocatalytic performance for degrading Rh.B under visible light irradiation than C3N4, phosphate–C3N4 and current well-known C3N4/graphene photocatalysts. It can be ascribed to the enhancement of the production of OH radicals which is due to the simultaneous presence of phosphate and graphene species. The surface phosphation and grafted graphene sheet enhanced the formation of unbound OH radicals instead of surface-bound OH radicals on the phosphate modified C3N4 surface while the grafted graphene accelerates the electron separation from excited C3N4. Moreover, the photocatalytic activity of the phosphate–C3N4/graphene photocatalysts can be optimized by monitoring the content of graphene that is about 2 wt%.