Fast electron transfer and enhanced visible light photocatalytic activity by using poly-o-phenylenediamine modified AgCl/g-C_3N_4 nanosheets

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.

One-step synthesis of graphitic carbon nitride nanosheets for efficient catalysis of phenol removal under visible light

Graphitic carbon nitride(g‐C3N4)nanosheet photocatalysts were synthesized via a facile impregnation‐thermal method.The as‐prepared materials were characterized and investigated as metal‐free photocatalysts for the degradation of phenol in aqueous solution under visible light.Results revealed that the g‐C3N4nanosheets exhibited a78.9%degradation for phenol after30min,which was much faster than that of the pristine g‐C3N4.Using Brunauer‐Emmett‐Teller theory,the surface area of g‐C3N4nanosheets was103.24m2/g,which was much larger than that of g‐C3N4.The larger surface area increases the contact area of the material with phenol,enhancing the photocatalytic activity.These results highlight the potential application of sustainable metal‐free photocatalysts in water purification.

Facile Synthesis of C3N4/Ag Composite Nanosheets as SERS Substrate for Monitoring the Catalytic Degradation of Methylene Blue

The C3N4/Ag composite nanosheets were facilely prepared via an in sire reduction process and Ag nanoparticles were well dispersed on the surface of C3N4 nanosheets. The unique two-dimensional structtlre and strong interactions between C3N4 nanosheets and Ag nanoparticles contributed the good surthce-enhanced Raman scattering（SERS） property due to the electromagnetic field enhancement. In addition, the as-prepared CaN4/Ag composite nanosheets could be used as catalysts or photocatalyst for the degradation of methylene blue（MB） in the presence of NaBH4 or under visible light. Therefore, a facile SERS monitoring of the catalytic and photocatalytic degradation process of MB and the determination of the reaction kinetics were developed.