Graphene quantum dots （GODs） recently emerge as the new and appealing nanophotocatalyst because of their low-cost, environmental compatibility and the ability to facilitate the charge migration and prolong the charg...Graphene quantum dots （GODs） recently emerge as the new and appealing nanophotocatalyst because of their low-cost, environmental compatibility and the ability to facilitate the charge migration and prolong the charge lifetimes. In this work, a visible photocatalyst of S-doped graphene quantum dots （S-GQDs） was prepared by a facile hydrothermal synthesis using 1,3,6-trinitropyrene and Na2S as precursors. The well crystallization and monodispersity as well as the chemical environment of S-GQDs were characterized by transmission electron microscopy, atom force microscopy and X-ray photoelectron spectrum. A superior photocatalytic performance of S-GQDs was demonstrated for degradation of basic fuchsin under visible light irradiation. Furthermore, the possible photocatalytic mechanism was proposed based on the trapping experiments of active species.展开更多
The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precurs...The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precursors in this paper. The properties of as-synthesized materials were studied by X-ray diffraction（XRD）, transmission electron microscopy（TEM）, vibrating sample magnetometry（VSM）, diffuse reflectance spectroscopy（DRS）, and ultraviolet–visible（UV-Vis） spectroscopy. The effects of irradiation time, methylene blue（MB） concentration, catalyst dosage, and p H value upon the degradation of MB were studied. Magnetic properties of the samples showed that both as-synthesized Fe/FeS photocatalysts are magnetically recoverable, eliminating the need for conventional filtration steps. Degradation of 5 ppm of the MB solution by mechano-thermally synthesized Fe/FeS with a photocatalyst dosage of 1 kg/m^3 at pH 11 can reach 96% after 12 ks irradiation under visible light. The photocatalytic efficiency is higher in alkaline solution. The kinetics of photocatalytic degradation in both samples is controlled by a first-order reaction. However, the rate-constant value in the thermally synthesized Fe/FeS photocatalyst sample is only 1.5 times greater than that of the mechano-thermally synthesized one.展开更多
High-efficiency photocatalysts are of great significance for the application of photocatalytic technology in water treatment.In this study,N/Cu co-doped ZnS nanosphere photocatalys(N/Cu-ZnS) is synthesized by a hydrot...High-efficiency photocatalysts are of great significance for the application of photocatalytic technology in water treatment.In this study,N/Cu co-doped ZnS nanosphere photocatalys(N/Cu-ZnS) is synthesized by a hydrothermal method for the first time.After doping,the tex ture of nanosphere becomes loose,the nanometer diameter is reduced,making the specific surface area of catalyst increased from 34.73 to 101.59 m^(2)/g.The characterization results show that more ZnS (111) crystal planes are exposed by N/Cu co-doping;the calculations of density functional theory show that N/Cu co-doping can increase the catalytic activity of the ZnS (111) crystal plane,enhance the adsorption capacity of (111) crystal plane to O_(2)and promote the generation of·O_(2)-.The energy levels of the introduced impurities can be hybridized with the energy levels of S and Zn at the top of valence band and the bottom o conduction band,which makes the band gap narrower,thus enhancing the absorption o visible light.Compared with pure ZnS,the degradation rates of 2,4-dichlorophenol (2,4-DCP and tetracycline (TC) by N/Cu-ZnS under visible light (>420 nm) are increased by 83.7 and51 times,respectively.In this research,a promising photocatalyst for photocatalytic degra dation of organic pollutants in wastewater is provided.展开更多
基金financial support from the Zhejiang Provincial Natural Science Foundation of China (Nos. LY17B050007, LY15B050006)521 Talent Project of ZSTU
文摘Graphene quantum dots （GODs） recently emerge as the new and appealing nanophotocatalyst because of their low-cost, environmental compatibility and the ability to facilitate the charge migration and prolong the charge lifetimes. In this work, a visible photocatalyst of S-doped graphene quantum dots （S-GQDs） was prepared by a facile hydrothermal synthesis using 1,3,6-trinitropyrene and Na2S as precursors. The well crystallization and monodispersity as well as the chemical environment of S-GQDs were characterized by transmission electron microscopy, atom force microscopy and X-ray photoelectron spectrum. A superior photocatalytic performance of S-GQDs was demonstrated for degradation of basic fuchsin under visible light irradiation. Furthermore, the possible photocatalytic mechanism was proposed based on the trapping experiments of active species.
基金financial support of University of Tehran for this researchfinancial support of Iran Nanotechnology Initiative Council
文摘The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precursors in this paper. The properties of as-synthesized materials were studied by X-ray diffraction（XRD）, transmission electron microscopy（TEM）, vibrating sample magnetometry（VSM）, diffuse reflectance spectroscopy（DRS）, and ultraviolet–visible（UV-Vis） spectroscopy. The effects of irradiation time, methylene blue（MB） concentration, catalyst dosage, and p H value upon the degradation of MB were studied. Magnetic properties of the samples showed that both as-synthesized Fe/FeS photocatalysts are magnetically recoverable, eliminating the need for conventional filtration steps. Degradation of 5 ppm of the MB solution by mechano-thermally synthesized Fe/FeS with a photocatalyst dosage of 1 kg/m^3 at pH 11 can reach 96% after 12 ks irradiation under visible light. The photocatalytic efficiency is higher in alkaline solution. The kinetics of photocatalytic degradation in both samples is controlled by a first-order reaction. However, the rate-constant value in the thermally synthesized Fe/FeS photocatalyst sample is only 1.5 times greater than that of the mechano-thermally synthesized one.
基金supported by CNPC safety and environmental protection key technology research and promotion project (No. 2017D-4613)Sub project of national science and technology major project (No. 2016ZX05040-003)China University of Petroleum (East China) Graduate Innovative Engineering Project (No. YCX2020039)。
文摘High-efficiency photocatalysts are of great significance for the application of photocatalytic technology in water treatment.In this study,N/Cu co-doped ZnS nanosphere photocatalys(N/Cu-ZnS) is synthesized by a hydrothermal method for the first time.After doping,the tex ture of nanosphere becomes loose,the nanometer diameter is reduced,making the specific surface area of catalyst increased from 34.73 to 101.59 m^(2)/g.The characterization results show that more ZnS (111) crystal planes are exposed by N/Cu co-doping;the calculations of density functional theory show that N/Cu co-doping can increase the catalytic activity of the ZnS (111) crystal plane,enhance the adsorption capacity of (111) crystal plane to O_(2)and promote the generation of·O_(2)-.The energy levels of the introduced impurities can be hybridized with the energy levels of S and Zn at the top of valence band and the bottom o conduction band,which makes the band gap narrower,thus enhancing the absorption o visible light.Compared with pure ZnS,the degradation rates of 2,4-dichlorophenol (2,4-DCP and tetracycline (TC) by N/Cu-ZnS under visible light (>420 nm) are increased by 83.7 and51 times,respectively.In this research,a promising photocatalyst for photocatalytic degra dation of organic pollutants in wastewater is provided.
