A highly efficient visible-light-driven photocatalyst Ag 3 PO 4 /AgI-Graphene (Ag 3 PO 4 /AgI-G) was synthesized through a chemical coprecipitation procedure. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were performed to study the physicochemical structural of the photocatalysts. The photocatalytic activity of the samples was examined by the carbamazepine (CBZ) degradation under artificial visible light and natural sunlight irradiation. Experimental results indicated that the introduction of low mass content of graphene enhanced the photocatalytic performance of Ag 3 PO 4 /AgI, and the photocatalytic degradation efficiency of CBZ over Ag 3 PO 4 /AgI-3%G (mass ratio of graphene:Ag 3 PO 4 /AgI = 3:100) reached 93.06% within 21 min, which was much higher than that over pure Ag 3 PO 4 (26.92%) and Ag 3 PO 4 /AgI (74.38%). UV–vis diffuse reflectance spectra, photoluminescence (PL) spectra, transient photocurrent responses and electrochemical impedance spectra (EIS) of the samples were conducted to verify the high photocatalytic performance of the Ag 3 PO 4 /AgI-3%G. In addition, possible photocatalytic degradation pathways of CBZ were proposed based on the analysis of transformation products during the reaction. The reactive species trapping experiments and Electron spin resonance (ESR) analysis demonstrated that h + and O 2 − were the main active oxidant species responsible for CBZ photodegradation. The photocatalytic degradation mechanism of CBZ over Ag 3 PO 4 /AgI-3%G under visible light irradiation was schematically proposed. This study not only provides a new technique for the synthesis of Ag 3 PO 4 -based photocatalysts with high photocatalytic activity, but also demonstrates that the Ag 3 PO 4 /AgI-3%G composite could be a promising photocatalyst for the treatment of waters containing CBZ.
Z-scheme Ag 3 PO 4 /AgI composites were synthesized by facile in-situ anion-exchange method at room temperature (RT). All the catalysts have excellent affinity to dyes and adsorb larger than 70 % of Methyl blue. The fastest adsorption equilibrium of Ag 3 PO 4 ( q e : 25.9278 mg/g) with low specific surface area (SSA: 4.6624 m 2 /g) can be rapidly attained for 6 min. The best color removal efficiency (RE) for Methyl blue over all the composites can rapidly increase to 100 % within 45 min. Meanwhile, the highest RE for RhB over S3 is 98.9 % for 60 min, and corresponding rate constant ( k ) is 0.07018 min −1 . After adding NaCl or Na 2 CO 3 into sonocatalysis, because of the formation of novel ternary AgCl/Ag 3 PO 4 /AgI and Ag 2 CO 3 /Ag 3 PO 4 /AgI during sonocatalytic process, the best REs for RhB over S3 composite increase from 89.8 % (no scavenger) to 98.2 % (1.2 mM NaCl), or to 97.6 % (1.8 mM Na 2 CO 3 ) for 30 min, respectively, and the REs for Methyl blue over S3 are about 100 % for 10 min. From single Ag 3 PO 4 to binary Ag 3 PO 4 /AgI, and to ternary Ag 2 CO 3 /Ag 3 PO 4 /AgI or AgCl/Ag 3 PO 4 /AgI, REs are significantly enhanced. New redox energy bands and charge transfer channels lead to efficiently spatial charge separation and further activation of hole ( h + ), superoxide anions (·O 2 − ), hydroxyl radicals (·OH). Additionally, the relation among oxygen vacancies (O v ), Zeta potential and RE was discussed in detail. Density functional theory (DFT) calculations were used to make clear charge transfer and sonocatalytic mechanism. The evaluation of used samples, adsorption kinetics and modes, diverse degradation pathways and sonocatalytic mechanisms were also discussed in detail. The work provides a novel in-situ strategy for real-time control of catalytic performance by rapidly forming new phase during catalysis at RT. Furthermore, the strategy obviously facilitates real-time development of rare more than ternary composites for enhanced catalytic performance.
Jing Wang,Tianli Yang,Ren He,Kehui Xue,Renrui Sun,Wenlei Wang,Juntao Wang,Ting Yang,Yuanlan Wang
Ternary heterostructure nanotubes of In 2 S 3 -CdIn 2 S 4 @X(X = Ag, Ag 3 PO 4 , AgI) were synthesized with enhanced photocatalytic activity for efficiently degrading pollutants. Electron beam irradiation was employed to artificially introduce interface defects to the heterostructure nanotubes. The experimental results for degrading carmine and Cr 6+ under visible light irradiation showed that the photocatalytic efficiency of In 2 S 3 -CdIn 2 S 4 was improved to some extent by the introduction of silver compounds. DRS results confirmed that the band gaps of In 2 S 3 -CdIn 2 S 4 were reduced to 1.62 eV and 1.58 eV by introducing Ag 3 PO 4 and AgI, respectively. Interestingly, the band gap of In 2 S 3 -CdIn 2 S 4 @AgI after electron beam irradiation was further reduced to 1.56 eV, resulting in that the degradation time of both Cr 6+ and carmine by In 2 S 3 -CdIn 2 S 4 @AgI after high-energy electron beam irradiation was shortened to only 5 min. The XRD spectra of the photocatalysts after five cycles could maintain the original crystal form to a large extent. The O H stretching vibration peaks of In 2 S 3 -CdIn 2 S 4 @AgI after electron beam irradiation at 3387 cm −1 became wider and sharper, thus indicating that the number of free hydroxyl groups on the heterostructure surface significantly increased. PL results showed that electron beam irradiation could significantly reduce the PL emission peak and enhance the utilization of photogenerated charge carriers. EIS results further confirmed that In 2 S 3 -CdIn 2 S 4 @AgI processed by electron beam irradiation had higher photogenerated electron-hole separation efficiency. Based on the experimental results, a feasible reaction pathway and photocatalytic mechanism for the degradation of carmine was investigated. ESR results showed that the main active groups in the whole photocatalytic system were •O 2 – and h + .
危险品化学品经营许可证（带存储）