Electrochemical detection of 3-methyl-4-nitrophenol (MNP) in direct phenol oxidation occurs at high potentials and generally leads to progressive passivation of the electrochemical sensor. This study describes the use...Electrochemical detection of 3-methyl-4-nitrophenol (MNP) in direct phenol oxidation occurs at high potentials and generally leads to progressive passivation of the electrochemical sensor. This study describes the use of a carbon fiber microelectrode modified with a tetrasulfonated nickel phthalocyanine complex for the detection of MNP at a lower potential than that of direct phenol oxidation. The MNP voltammogram showed the presence of an anodic peak at -0.11 V vs SCE, corresponding to the oxidation of the hydroxylamine group generated after the reduction of the nitro group. The effect of buffer pH on the peak current and SWV parameters such as frequency, scan increment, and pulse amplitude were studied and optimized to have better electrochemical response of the proposed sensor. With these optimal parameters, the calibration curve shows that the peak current varied linearly as a function of MNP concentration, leading to a limit of detection (LoD) of 1.1 μg/L. These results show an appreciable sensitivity of the sensor for detecting the MNP at relatively low potentials, making it possible to avoid passivation phenomena.展开更多
Up to now,facile and pollution-free routes for catalyst preparation are in high demand.In this study,a green and cost-effective strategy was successfully developed to construct platinum/graphene aerogel(Pt/GA)nanocomp...Up to now,facile and pollution-free routes for catalyst preparation are in high demand.In this study,a green and cost-effective strategy was successfully developed to construct platinum/graphene aerogel(Pt/GA)nanocomposites by the co-reduction of graphene oxides(GO)and chloroplatinic acid(H_(2)PtCl6$6H_(2)O)with the assists of g-ray irradiation in the absence of any other reductants.Characterization studies indicated that the energy of g-ray irradiation and the hole scavenger isopropanol(IPA)played a vital role in forming small Pt nanoparticles with uniform size of~3 nm on the surface of graphene aerogel(GA).Furthermore,Pt/GA synthesized with a mass ratio of 2:1(Pt/GA-2)exhibited a lowest activation energy value and outstanding catalytic properties for the reduction of 4-nitrophenol(4-NP).The excellent catalytic and cycling performance suggest that Pt/GA-2 catalyst has a promising prospect for the reduction of nitroaromatic compounds in wastewater treatment and other industrial applications.展开更多
Synthesizing atomically precise Ag nanoclusters(NCs),which is essential for the general development of NCs,is quite challenging.In this study,we report the synthesis of high-purity atomically precise Ag NCs via a kine...Synthesizing atomically precise Ag nanoclusters(NCs),which is essential for the general development of NCs,is quite challenging.In this study,we report the synthesis of high-purity atomically precise Ag NCs via a kinetically controlled strategy.The Ag NCs were prepared using a mild reducing agent via a one-pot method.The as-prepared Ag NCs were confirmed to be Ag_(49)(D-pen)_(24)(D-pen:D-penicillamine)on the basis of their matrix-assisted laser desorption ionization time-of-flight mass spectrometric and thermogravimetric characteristics.The interfacial structures of the Ag NCs were illustrated by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy.The Ag NCs were supported on activated carbon(AC)to form Ag NCs/AC,which displayed excellent activity for the catalytic reduction of 4-nitrophenol with a kinetic reaction rate constant k of 0.21 min^(-1).Such a high k value indicates that the composite could outperform several previously reported catalysts.Moreover,the catalytic activity of Ag NCs/AC remained nearly constant after six times of recycle,which suggests its excellent stability.展开更多
In the present study,a film consisting of TiO_2 doped with copper was prepared for efficiently decomposing 4-nitrophenol(4-NP) by photocatalysis.The preparing process of TiO_2 doped with copper includes two procedures...In the present study,a film consisting of TiO_2 doped with copper was prepared for efficiently decomposing 4-nitrophenol(4-NP) by photocatalysis.The preparing process of TiO_2 doped with copper includes two procedures:preparing Ti(OH)_4 doped with copper and synthesizing anatase and rutile TiO_2 doped with copper.Ti(OH)_4 doped with copper could be achieved by hydrolyzing TiCl_4in the mixed solution containing deionized water and copper oxalate.The Ti(OH)_4 doped with copper can be gained successfully by the following procedures:rinsing,drying and vacuum drying.The Ti(OH)_4 doped with copper could be converted into anatase TiO_2 doped with copper and rutile TiO_2 doped with copper by incineration for 4.5 h at 723 and 1 073 K,respectively.Characterizations of anatase TiO_2 doped with copper and rutile TiO_2 doped with copper were determined by X-ray diffraction(XRD) and energy dispersion of X-ray(EDX).Anatase and rutile TiO_2 doped with copper were dissolved in a mixed solution containing isopropanol and diethylamine.Stainless electrode was submerged into with the solutions,the film of TiO_2 was formed by drying the thin layer at a ramp rate of 3℃/min until 373 K,and this temperature was held for 1 h.The temperature of the oven was subsequently increased to a final temperature of 823 K at a ramp rate of 3℃/min,and was held at this value for 1 h.The stainless steel covered with modified TiO_2 film was utilized as the anode.The stainless steel mesh was used as the cathode.The cathode and anode were connected with the source and immersed into the solution with 100 mg/L 4-NP.The whole reaction on photocatalysis was perfectly carried out after ultraviolet radiation and aerator were run.The experimental results showed that:cracking ratio of 4-NP ring,the removal ratio of chemical oxygen demand(COD) and total organic carbon(TOC) were respectively more than 90%,80% and 80% within 2 h.Degradation of 4-NP implied its potential application in associated wastewater.展开更多
3-methyl-4-nitrophenol (MNP) is the main by-product of the organophosphate insecticide fenitrothion (FT), used in locust control. MNP is highly toxic because it is an endocrine disruptor and then may cause adverse in ...3-methyl-4-nitrophenol (MNP) is the main by-product of the organophosphate insecticide fenitrothion (FT), used in locust control. MNP is highly toxic because it is an endocrine disruptor and then may cause adverse in the biological systems. Then, it is necessary to develop analytical methods for determination of this pollutant in the environment. In this sense, we reported herein the development of an electrochemical sensor for the detection of 3-methyl-4-nitrophenol (MNP), one of the metabolites of fenitrothion (FT), by using naked and modified carbon fiber microelectrode (CFME) by nickel tetrasulfonated phthalocyanine polymer (CFME/p-NiTSPc). The voltammogram showed that MNP presents one irreversible anodic peak corresponding to the oxidation of the phenol group at 0.9 V vs Ag/AgCl. The effect of pH of the buffer on the peak current and SWV parameters such as frequency, scan increment and pulse amplitude were investigated in order to optimize the electrochemical response of the sensor. The obtained results lead to the following optimum value: pH = 6;frequency = 25 Hz, pulse amplitude = 50 mV, scan increment = 10 mV. With these optimum values, the calibration curves show that the peak current varied linearly upon MNP concentration leading to a limit of detection (LoD) for naked CFME close to 3 μg/L whereas for CFME modified by p-NiTSPc, it reaches 0.75 μg/L. This results prove that the presence of p-NiTSPc increasing the sensitivity of the sensor could be used to monitor 3-methyl-4-nitrophenol residue in real matrix.展开更多
Toward the imperative treatment of the industrial wastewater containing 4-nitrophenol(4-NP)and industrial solid waste red mud(RM),an innovative approach of“Using waste to treat waste”is developed.Valuable element Al...Toward the imperative treatment of the industrial wastewater containing 4-nitrophenol(4-NP)and industrial solid waste red mud(RM),an innovative approach of“Using waste to treat waste”is developed.Valuable element Al is leached from the RM first,the resultant NaAlO_(2) solution is hydrothermally converted toγ-AlOOH hierarchical porous microspheres(RMγ-AlOOH HPMSs,average diameter:2.0μm,SBET:77.81 m^(2) g^(-1),pore volume:0.38 cm^(3) g^(-1))in the presence of urea.The subsequent mild thermal conversion results inγ-Al_(2)O_(3) hierarchical porous microspheres(RMγ-Al_(2)O_(3) HPMSs).Both of the RMγ-AlOOH and RMγ-Al_(2)O_(3) HPMSs are employed as the Pd catalyst support for the catalytic reduction of 4-NP.Particularly,the as-obtained composite Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) exhibit excellent catalytic activities with superior knor as 8204.5 and 4831.4 s^(-1) g^(-1),respectively,significantly higher than that of most Pd based catalysts.Moreover,the excellent catalytic stability and durability of the Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) within 10 successive cycles of reduction enable the present industrial solid waste RM inducedγ-AlOOH andγ-Al_(2)O_(3) HPMSs as great promising Pd catalyst support for the reduction of the industrial wastewater containing 4-NP.展开更多
In this work,a simple synthesis of sulfur doped graphitic carbon nitride(S-g-C3N4)act as a support cum stabilizers for gold nanoparticles(Au)and its was characterized by UV–vis and XRD to measure the absorbance and c...In this work,a simple synthesis of sulfur doped graphitic carbon nitride(S-g-C3N4)act as a support cum stabilizers for gold nanoparticles(Au)and its was characterized by UV–vis and XRD to measure the absorbance and crystallinity,respectively.The functional group and morphology of the samples were identified using FT-IR and TEM.Finally,the Au@S-g-C3N4 nanocatalyst exhibits good catalytic performance and stability in the reduction of hazardous 4-nitrophenol(NP)compared to S-g-C3N4 using Na BH4.Moreover,the Au@S-g-C3N4 nanocomposite holds a good catalytic efficiency(near 100%)achieved by within 5 min.The highest catalytic reduction of NP is due to the synergistic effect of Au nanoparticles decorated on S-g-C3N4.The fast electron transfer reduction mechanism was elucidated and discussed.Excellent reusability and stability of the developed nanocomposites were also observed in consecutive reduction experiments.The filtering and catalyzing device was used for the direct conversion of NP polluted water.This method can open a new avenue for the metal nanoparticles based carbon materials heterogeneous catalyst and its reduction of toxic contaminants.展开更多
Conversion of nitroarenes to aminoarenes has attracted great attention in pharmaceutical industry, agricultural production, environmental protection and chemical catalysis area. In this work, ficin capped gold nanoclu...Conversion of nitroarenes to aminoarenes has attracted great attention in pharmaceutical industry, agricultural production, environmental protection and chemical catalysis area. In this work, ficin capped gold nanoclusters(ficin@AuNCs) were prepared for the reduction of 4-nitrophenol to 4-aminophenol.The proposed catalyst was characterized by transmission electron microscopy,dynamic light scattering, fluorescence spectra and UV-Vis spectra. With NaBH4 as the reducing agent, the reduction reaction could carry out completely within 10 min at 25 ℃. Interestingly, the resultant catalyst exliibited size-related properties in the reduction, smaller ficin@AuNCs exhibited liigher catalytic activity. Its present pseudo-first-order rate constant was found to be 2.95×10^-3 s^-1 and the catalytic activation energy was 27.7 kJ/mol. Moreover, ficin@AuNCs-based catalyst displayed good stability, heading to 4-nitrophenol conversion of 98.5%-100.0% after six consecutive cycles. It has shown a great potential in construction of unique catalysts based on AuNCs for reduction reaction.展开更多
In this study,the enhancement of catalytic activity of ceria when modified with co-catalysts such as graphitic carbon nitride and silver was establishe d.The material was synthe sized using phytogenic combustion metho...In this study,the enhancement of catalytic activity of ceria when modified with co-catalysts such as graphitic carbon nitride and silver was establishe d.The material was synthe sized using phytogenic combustion method,a green alternative to the traditional preparative routes.The catalyst was characterized using XRD,FTIR,SEM,EDX,XPS and TEM techniques.The synergistic effect of the composite CeO2/g-C3 N4/Ag was tested for catalytic reduction of 4-nitrophenol in the prese nce of sodium borohydride.The reaction was carried out at room tempe rature without any light source or exte rnal stirring.The individual and combined effects of four parameters,viz.,concentration of 4-NP,amount of catalyst,amount of NaBH4 and time for the reduction of reduction 4-NP were investigated using Box-Behnken design of response surface methodology(RSM).This statistical model was used to optimize the reaction conditions for maximum reduction of 4-NP.The optimum conditions for the reduction reaction are found to be 0.01 mmol/L 4-NP,15 mg catalyst,20 mg NaBH4 and 13.7 min time interval.展开更多
In this study,an efficient catalyst Ag@g-C_(3)N_(4) nanocomposite was successfully synthesized through a simple green reaction,and the characterizations through XRD,FTIR,SEM,BET and XPS were also studied.The activitie...In this study,an efficient catalyst Ag@g-C_(3)N_(4) nanocomposite was successfully synthesized through a simple green reaction,and the characterizations through XRD,FTIR,SEM,BET and XPS were also studied.The activities of Ag@g-C_(3)N_(4) were investigated toward the reduction of 4-nitrophenol to their corresponding aminophenol compounds in the presence of excess NaBH_(4) as a reducing agent.The Ag@g-C_(3)N_(4) nanocomposites exhibited high catalytic activities,in which a 92.2%4-nitrophenol conversion in 10 min and the apparent rate constant K_(app)=264.27×10^(-3) min-1were obtained.The as-prepared Ag@g-C_(3)N_(4) nanocomposites showed great potential in catalytically inducing the reduction of 4-nitrophenol,which makes them economically and energy conservation attractive from industrial waste water treatment.展开更多
In this study,we report the synthesis of novel palladium nanoflowers(Pd NFs)on amino-functionalized fullerene(C60-NH2)by hydrothermal self-assembly growth using ethylenediamine(EA)as a functional reagent.The successfu...In this study,we report the synthesis of novel palladium nanoflowers(Pd NFs)on amino-functionalized fullerene(C60-NH2)by hydrothermal self-assembly growth using ethylenediamine(EA)as a functional reagent.The successful formation of Pd nanoflowers supported amino-functionalized fullerene(C60-NH2/Pd NFs)is evidenced by UV-vis and powder X-ray diffraction(XRD).The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy(TEM)and Fourier-transform infrared(FT-IR)techniques.The supported Pd nanoflowers(Pd NFs/C60-NH2)exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol(4-NP).It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol(4-AP)(99%in 2.0 min)with a turnover frequency of 12.35 min^-1.Its excellent catalytic stability and durability offer the promising application in catalysis.展开更多
As a component of diesel exhaust particles,3-methyl-4-nitrophenol(4-nitro-m-cresol,PNMC) is also a metabolite of the insecticide fenitrothion and imposes hazardous effects on human health.In the present study,the alle...As a component of diesel exhaust particles,3-methyl-4-nitrophenol(4-nitro-m-cresol,PNMC) is also a metabolite of the insecticide fenitrothion and imposes hazardous effects on human health.In the present study,the alleviative effect of a common antioxidant flavonoid quercetin on mouse germ cells intoxicated by PNMC was inves-tigated.Results showed that a single intraperitoneal injection of PNMC at 100 mg/kg induced severe testicular damage after one week.PNMC-treated mice showed a significant loss of germ cells(approximate 40% loss of round germ cells).PNMC caused an increase of hydroxyl radical and hydrogen peroxide production and lipid peroxidation,as well as a decrease in glutathione level,superoxide dismutase and glutathione peroxidase activities.Furthermore,treatment of PNMC increased expression of the pro-apoptotic protein Bax and decreased expression of the anti-apoptotic protein Bcl-XL in germ cells.In addition,testicular caspase-3 activity was significantly up-regulated and germ cell apoptosis was significantly increased in the PNMC-treated mice.In contrast,combined administration of quercetin at 75 mg/kg significantly attenuated PNMC-induced testicular toxicity.These results indicate that the antioxidant quercetin displays a remarkable protective effect on PNMC-induced oxidative damage in mouse testes and may represent an efficient supplement to attenuate reproductive toxicity by environmental toxicants to ensure healthy sperm production.展开更多
Here,Ag_2S nanoparticles on reduced graphene oxide(Ag_2S NPs/RGO) nanocomposites with relatively good distribution are synthesized for the first time by conversing Ag NPs/RGO to Ag_2S NPs/RGO via a facile hydrothermal...Here,Ag_2S nanoparticles on reduced graphene oxide(Ag_2S NPs/RGO) nanocomposites with relatively good distribution are synthesized for the first time by conversing Ag NPs/RGO to Ag_2S NPs/RGO via a facile hydrothermal sulfurization method.As an noval catalyst for the reduction of 4-nitrophenol(4-NP),it only takes 5 min for Ag_2S NPs/RGO to reduce 98% of 4-NP,and the rate constant of the composites is almost 13 times higher than that of Ag NPs/RGO composites.The high catalytic activity of Ag_2S NPs/RGO can be attributed to the following three reasons:(1) Like metal complex catalysts,the Ag_2S NPs is also rich with metal center Ag(δ^+),with pendant base S(δ) close to it,and thus the Ag and basic S function as the electron-acceptor and proton-acceptor centers,respectively,which facilitates the catalyst reaction;(2)RGO features the high adsorption ability toward 4-NP which provides a high concentration of 4-NP near the Ag_2S NPs;and(3) electron transfer from RGO to Ag_2S NPs,facilitating the uptake of electrons by 4-NP molecules.展开更多
Active new ceria-promoted platinum supported on ZSM-5 catalysts were prepared and characterized by X-ray diffraction(XRD),Fourier transform infrared spectra(FTIR),transform electron microscopy(TEM),temperature program...Active new ceria-promoted platinum supported on ZSM-5 catalysts were prepared and characterized by X-ray diffraction(XRD),Fourier transform infrared spectra(FTIR),transform electron microscopy(TEM),temperature programmed desorption(TPD),and FTIR of CO adsorption.The samples were prepared by the incipient wetness impregnation method and calcined at 500℃.The XRD patterns and FTIR spectra prove that the zeolite framework is kept unaltered after metal loadings.TEM images prove the presence of Pt nanoparticles with particle size starting from 14 to 27 nm.The FTIR data suggest the formation of Pt-O-Ce linkage.In-situ FTIR of CO adsorption over reduced samples proves the presence of Pt~0 only,and no Pt^(n+)-CO species are detected.The prepared catalysts were tested in both oxidation reaction(CO oxidation) in the gas phase and in reduction reaction(4-nitrophenol reduction) in the aqueous medium.Firstly,CO oxidation by O_(2) results in the formation of a CO_(2) peak at 2347 cm^(-1) as the only CO oxidation product in the studied frequency range.The intensity of the CO_(2) peak increases after the addition of Ce,and it is 4 times higher in Pt_(1) Ce_(0.5)ZSM-5 than that in the Ce-free sample.According to the FTIR data and previous reports,the increase in the catalytic activity may be due to the formation of Pt-O-Ce linkage.Secondly,Ce-promoted Pt_(1) ZSM5 also exhibits enhanced catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol by NaBH_(4) in the aqueous medium.The first-order rate constant of the reduction increases ≈13 times after incorporating equal ratios of Pt and Ce(Pt_(1) Ce_(1)ZSM-5),and the activation energy(E_(a)) decreases to 40% of that in the reaction over Pt_(1) ZSM-5.展开更多
Generating heterophase structures in nanomaterials,e.g.,heterophase metal nanocrystals,is an effective way to tune their physicochemical properties because of their high-energy nature and unique electronic environment...Generating heterophase structures in nanomaterials,e.g.,heterophase metal nanocrystals,is an effective way to tune their physicochemical properties because of their high-energy nature and unique electronic environment of the generated interfaces.However,the direct synthesis of heterophase metal nanocrystals remains a great challenge due to their unstable nature.Herein,we report the in situar direct synthesis of heterophase Ni nanocrystals on graphene.The heterostructure of face-centered cubic(fee)and hexagonal close-packed(hep)phase was generated via the epitaxial growth of hep Ni and the partial transformation of fee Ni and stabilized by the anchoring effect of graphene toward fee Ni nanocrystal and the preferential adsorption of surfactant polyethylenimine(PEI)toward epitaxial hep Ni.Comparing with the fee Ni nanocrystals grown on graphene,the heterophase(fcc/hcp)Ni nanocrystals in situ grown on graphene showed a greatly improved catalytic activity and reusability in 4-nitrophenol(4-NP)reduction to 4-aminophenol(4-AP).The measured apparent rate constant and the activity parameter were 2.958 min^(-1) and 102 min^(-1)·mg^(-1),respectively,higher than that of the best reported non-noble metal catalysts and most noble metal catalysts.The control experiments and density functional theory calculations reveal that the interface of the fee and hep phases enhances the adsorption of substrate 4-NP and thus facilitates the reaction kinetics.This work proves the novel idea for the rational design of heterophase metal nanocrystals by employing the synergistic effect of surfactant and support,and also the potential of creating the heterostructure for enhancing their catalytic reactivity.展开更多
The fabrication of highly active and easily recyclable Pd-based catalyst is meaningful for their practical application.Herein,a Pd-based dip-catalyst(Pd@Pyr-GDY)is fabricated on graphdiyne(Pyr-GDY)grown on copper foam...The fabrication of highly active and easily recyclable Pd-based catalyst is meaningful for their practical application.Herein,a Pd-based dip-catalyst(Pd@Pyr-GDY)is fabricated on graphdiyne(Pyr-GDY)grown on copper foam,and applied in the reduction of nitroarenes.Specially,the as-formed Pd@Pyr-GDY shows good catalytic performance toward the reduction of 4-nitrophenol(4-NP)to 4-aminophenol(4-AP)by NaBH4 with a rate constant k value of 3.84 min^(−1),which is 12-fold higher than that of the commercial Pd/C.More importantly,Pd@Pyr-GDY could be easily and rapidly recovery from the reaction medium and no distinct inactivation was found after six cycles of the reaction.This work presents an easy way to design an efficient and easily recyclable Pd-based catalyst for practical use.展开更多
文摘Electrochemical detection of 3-methyl-4-nitrophenol (MNP) in direct phenol oxidation occurs at high potentials and generally leads to progressive passivation of the electrochemical sensor. This study describes the use of a carbon fiber microelectrode modified with a tetrasulfonated nickel phthalocyanine complex for the detection of MNP at a lower potential than that of direct phenol oxidation. The MNP voltammogram showed the presence of an anodic peak at -0.11 V vs SCE, corresponding to the oxidation of the hydroxylamine group generated after the reduction of the nitro group. The effect of buffer pH on the peak current and SWV parameters such as frequency, scan increment, and pulse amplitude were studied and optimized to have better electrochemical response of the proposed sensor. With these optimal parameters, the calibration curve shows that the peak current varied linearly as a function of MNP concentration, leading to a limit of detection (LoD) of 1.1 μg/L. These results show an appreciable sensitivity of the sensor for detecting the MNP at relatively low potentials, making it possible to avoid passivation phenomena.
基金This work is supported by the NSFC(No.21703193)Key Science and Technology Research Projects of Henan Province(No.182102310791)+1 种基金Key Scientific Research Project Plan of Colleges and Universities in Henan Province(No.18B520036)the Nanhu Scholars Program for Young Scholars of Xinyang Normal University in China.
文摘Up to now,facile and pollution-free routes for catalyst preparation are in high demand.In this study,a green and cost-effective strategy was successfully developed to construct platinum/graphene aerogel(Pt/GA)nanocomposites by the co-reduction of graphene oxides(GO)and chloroplatinic acid(H_(2)PtCl6$6H_(2)O)with the assists of g-ray irradiation in the absence of any other reductants.Characterization studies indicated that the energy of g-ray irradiation and the hole scavenger isopropanol(IPA)played a vital role in forming small Pt nanoparticles with uniform size of~3 nm on the surface of graphene aerogel(GA).Furthermore,Pt/GA synthesized with a mass ratio of 2:1(Pt/GA-2)exhibited a lowest activation energy value and outstanding catalytic properties for the reduction of 4-nitrophenol(4-NP).The excellent catalytic and cycling performance suggest that Pt/GA-2 catalyst has a promising prospect for the reduction of nitroaromatic compounds in wastewater treatment and other industrial applications.
基金financially supported by the Huaibei Normal University Doctoral Research Start-up Funding(No.15601012)the Natural Science Foundation of Anhui Provincial Department of Education(No.KJ2019A0598)+1 种基金the Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province,China(No.gxyq2019168)the Team of Superior Discipline of Chemistry(No.GFXK202108).
文摘Synthesizing atomically precise Ag nanoclusters(NCs),which is essential for the general development of NCs,is quite challenging.In this study,we report the synthesis of high-purity atomically precise Ag NCs via a kinetically controlled strategy.The Ag NCs were prepared using a mild reducing agent via a one-pot method.The as-prepared Ag NCs were confirmed to be Ag_(49)(D-pen)_(24)(D-pen:D-penicillamine)on the basis of their matrix-assisted laser desorption ionization time-of-flight mass spectrometric and thermogravimetric characteristics.The interfacial structures of the Ag NCs were illustrated by proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy.The Ag NCs were supported on activated carbon(AC)to form Ag NCs/AC,which displayed excellent activity for the catalytic reduction of 4-nitrophenol with a kinetic reaction rate constant k of 0.21 min^(-1).Such a high k value indicates that the composite could outperform several previously reported catalysts.Moreover,the catalytic activity of Ag NCs/AC remained nearly constant after six times of recycle,which suggests its excellent stability.
基金Environmental Protection Department of Jiangsu Province,China(No.2013023)Jiangsu Key Laboratory of Industrial Water-Conservation & Emission Reduction,China(No.IWCER201202)
文摘In the present study,a film consisting of TiO_2 doped with copper was prepared for efficiently decomposing 4-nitrophenol(4-NP) by photocatalysis.The preparing process of TiO_2 doped with copper includes two procedures:preparing Ti(OH)_4 doped with copper and synthesizing anatase and rutile TiO_2 doped with copper.Ti(OH)_4 doped with copper could be achieved by hydrolyzing TiCl_4in the mixed solution containing deionized water and copper oxalate.The Ti(OH)_4 doped with copper can be gained successfully by the following procedures:rinsing,drying and vacuum drying.The Ti(OH)_4 doped with copper could be converted into anatase TiO_2 doped with copper and rutile TiO_2 doped with copper by incineration for 4.5 h at 723 and 1 073 K,respectively.Characterizations of anatase TiO_2 doped with copper and rutile TiO_2 doped with copper were determined by X-ray diffraction(XRD) and energy dispersion of X-ray(EDX).Anatase and rutile TiO_2 doped with copper were dissolved in a mixed solution containing isopropanol and diethylamine.Stainless electrode was submerged into with the solutions,the film of TiO_2 was formed by drying the thin layer at a ramp rate of 3℃/min until 373 K,and this temperature was held for 1 h.The temperature of the oven was subsequently increased to a final temperature of 823 K at a ramp rate of 3℃/min,and was held at this value for 1 h.The stainless steel covered with modified TiO_2 film was utilized as the anode.The stainless steel mesh was used as the cathode.The cathode and anode were connected with the source and immersed into the solution with 100 mg/L 4-NP.The whole reaction on photocatalysis was perfectly carried out after ultraviolet radiation and aerator were run.The experimental results showed that:cracking ratio of 4-NP ring,the removal ratio of chemical oxygen demand(COD) and total organic carbon(TOC) were respectively more than 90%,80% and 80% within 2 h.Degradation of 4-NP implied its potential application in associated wastewater.
文摘3-methyl-4-nitrophenol (MNP) is the main by-product of the organophosphate insecticide fenitrothion (FT), used in locust control. MNP is highly toxic because it is an endocrine disruptor and then may cause adverse in the biological systems. Then, it is necessary to develop analytical methods for determination of this pollutant in the environment. In this sense, we reported herein the development of an electrochemical sensor for the detection of 3-methyl-4-nitrophenol (MNP), one of the metabolites of fenitrothion (FT), by using naked and modified carbon fiber microelectrode (CFME) by nickel tetrasulfonated phthalocyanine polymer (CFME/p-NiTSPc). The voltammogram showed that MNP presents one irreversible anodic peak corresponding to the oxidation of the phenol group at 0.9 V vs Ag/AgCl. The effect of pH of the buffer on the peak current and SWV parameters such as frequency, scan increment and pulse amplitude were investigated in order to optimize the electrochemical response of the sensor. The obtained results lead to the following optimum value: pH = 6;frequency = 25 Hz, pulse amplitude = 50 mV, scan increment = 10 mV. With these optimum values, the calibration curves show that the peak current varied linearly upon MNP concentration leading to a limit of detection (LoD) for naked CFME close to 3 μg/L whereas for CFME modified by p-NiTSPc, it reaches 0.75 μg/L. This results prove that the presence of p-NiTSPc increasing the sensitivity of the sensor could be used to monitor 3-methyl-4-nitrophenol residue in real matrix.
基金supported by the State Key Laboratory of Organic-Inorganic Composites (No.oic-202101009)State Key Laboratory of Chemical Engineering (No.SKL-ChE-21A02),China。
文摘Toward the imperative treatment of the industrial wastewater containing 4-nitrophenol(4-NP)and industrial solid waste red mud(RM),an innovative approach of“Using waste to treat waste”is developed.Valuable element Al is leached from the RM first,the resultant NaAlO_(2) solution is hydrothermally converted toγ-AlOOH hierarchical porous microspheres(RMγ-AlOOH HPMSs,average diameter:2.0μm,SBET:77.81 m^(2) g^(-1),pore volume:0.38 cm^(3) g^(-1))in the presence of urea.The subsequent mild thermal conversion results inγ-Al_(2)O_(3) hierarchical porous microspheres(RMγ-Al_(2)O_(3) HPMSs).Both of the RMγ-AlOOH and RMγ-Al_(2)O_(3) HPMSs are employed as the Pd catalyst support for the catalytic reduction of 4-NP.Particularly,the as-obtained composite Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) exhibit excellent catalytic activities with superior knor as 8204.5 and 4831.4 s^(-1) g^(-1),respectively,significantly higher than that of most Pd based catalysts.Moreover,the excellent catalytic stability and durability of the Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) within 10 successive cycles of reduction enable the present industrial solid waste RM inducedγ-AlOOH andγ-Al_(2)O_(3) HPMSs as great promising Pd catalyst support for the reduction of the industrial wastewater containing 4-NP.
基金supported financially by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future Planning(No.NRF-2017R1E1A1A01074266)the Industrial Fundamental Technology Development Program(No.10076350)funded by the Ministry of Trade,Industry and Energy(MOTIE)of Korea.
文摘In this work,a simple synthesis of sulfur doped graphitic carbon nitride(S-g-C3N4)act as a support cum stabilizers for gold nanoparticles(Au)and its was characterized by UV–vis and XRD to measure the absorbance and crystallinity,respectively.The functional group and morphology of the samples were identified using FT-IR and TEM.Finally,the Au@S-g-C3N4 nanocatalyst exhibits good catalytic performance and stability in the reduction of hazardous 4-nitrophenol(NP)compared to S-g-C3N4 using Na BH4.Moreover,the Au@S-g-C3N4 nanocomposite holds a good catalytic efficiency(near 100%)achieved by within 5 min.The highest catalytic reduction of NP is due to the synergistic effect of Au nanoparticles decorated on S-g-C3N4.The fast electron transfer reduction mechanism was elucidated and discussed.Excellent reusability and stability of the developed nanocomposites were also observed in consecutive reduction experiments.The filtering and catalyzing device was used for the direct conversion of NP polluted water.This method can open a new avenue for the metal nanoparticles based carbon materials heterogeneous catalyst and its reduction of toxic contaminants.
基金Supported by the National Natural Science Foundation of China(Nos.21635008,21621062).
文摘Conversion of nitroarenes to aminoarenes has attracted great attention in pharmaceutical industry, agricultural production, environmental protection and chemical catalysis area. In this work, ficin capped gold nanoclusters(ficin@AuNCs) were prepared for the reduction of 4-nitrophenol to 4-aminophenol.The proposed catalyst was characterized by transmission electron microscopy,dynamic light scattering, fluorescence spectra and UV-Vis spectra. With NaBH4 as the reducing agent, the reduction reaction could carry out completely within 10 min at 25 ℃. Interestingly, the resultant catalyst exliibited size-related properties in the reduction, smaller ficin@AuNCs exhibited liigher catalytic activity. Its present pseudo-first-order rate constant was found to be 2.95×10^-3 s^-1 and the catalytic activation energy was 27.7 kJ/mol. Moreover, ficin@AuNCs-based catalyst displayed good stability, heading to 4-nitrophenol conversion of 98.5%-100.0% after six consecutive cycles. It has shown a great potential in construction of unique catalysts based on AuNCs for reduction reaction.
文摘In this study,the enhancement of catalytic activity of ceria when modified with co-catalysts such as graphitic carbon nitride and silver was establishe d.The material was synthe sized using phytogenic combustion method,a green alternative to the traditional preparative routes.The catalyst was characterized using XRD,FTIR,SEM,EDX,XPS and TEM techniques.The synergistic effect of the composite CeO2/g-C3 N4/Ag was tested for catalytic reduction of 4-nitrophenol in the prese nce of sodium borohydride.The reaction was carried out at room tempe rature without any light source or exte rnal stirring.The individual and combined effects of four parameters,viz.,concentration of 4-NP,amount of catalyst,amount of NaBH4 and time for the reduction of reduction 4-NP were investigated using Box-Behnken design of response surface methodology(RSM).This statistical model was used to optimize the reaction conditions for maximum reduction of 4-NP.The optimum conditions for the reduction reaction are found to be 0.01 mmol/L 4-NP,15 mg catalyst,20 mg NaBH4 and 13.7 min time interval.
基金Project supported by the Natural Science Foundation of Fujian Province(No.2019J01747 and 2020J01803)Fujian Provincial Key Laboratory of Featured Materials in Biochemical Industry(FJKLFBCM202104)China NSF(No.41976150)。
文摘In this study,an efficient catalyst Ag@g-C_(3)N_(4) nanocomposite was successfully synthesized through a simple green reaction,and the characterizations through XRD,FTIR,SEM,BET and XPS were also studied.The activities of Ag@g-C_(3)N_(4) were investigated toward the reduction of 4-nitrophenol to their corresponding aminophenol compounds in the presence of excess NaBH_(4) as a reducing agent.The Ag@g-C_(3)N_(4) nanocomposites exhibited high catalytic activities,in which a 92.2%4-nitrophenol conversion in 10 min and the apparent rate constant K_(app)=264.27×10^(-3) min-1were obtained.The as-prepared Ag@g-C_(3)N_(4) nanocomposites showed great potential in catalytically inducing the reduction of 4-nitrophenol,which makes them economically and energy conservation attractive from industrial waste water treatment.
基金financially supported by the Natural Science Foundation of Shanxi Province,China(No.201801D121042)。
文摘In this study,we report the synthesis of novel palladium nanoflowers(Pd NFs)on amino-functionalized fullerene(C60-NH2)by hydrothermal self-assembly growth using ethylenediamine(EA)as a functional reagent.The successful formation of Pd nanoflowers supported amino-functionalized fullerene(C60-NH2/Pd NFs)is evidenced by UV-vis and powder X-ray diffraction(XRD).The morphology of Pd NFs over the C60-NH2 surface has been investigated by high-resolution transmission electron microscopy(TEM)and Fourier-transform infrared(FT-IR)techniques.The supported Pd nanoflowers(Pd NFs/C60-NH2)exhibit remarkably superior catalytic activity toward the reduction of 4-nitrophenol(4-NP).It exhibits remarkable UV-vis spectra response from 4-nitrophenol to 4-aminophenol(4-AP)(99%in 2.0 min)with a turnover frequency of 12.35 min^-1.Its excellent catalytic stability and durability offer the promising application in catalysis.
基金Project supported by the National Natural Science Foundation of China (No.31001041)the Chinese Universities Scientific Fund and Project of the Bureau of Education of Zhejiang Province (No.Y201018833),China
文摘As a component of diesel exhaust particles,3-methyl-4-nitrophenol(4-nitro-m-cresol,PNMC) is also a metabolite of the insecticide fenitrothion and imposes hazardous effects on human health.In the present study,the alleviative effect of a common antioxidant flavonoid quercetin on mouse germ cells intoxicated by PNMC was inves-tigated.Results showed that a single intraperitoneal injection of PNMC at 100 mg/kg induced severe testicular damage after one week.PNMC-treated mice showed a significant loss of germ cells(approximate 40% loss of round germ cells).PNMC caused an increase of hydroxyl radical and hydrogen peroxide production and lipid peroxidation,as well as a decrease in glutathione level,superoxide dismutase and glutathione peroxidase activities.Furthermore,treatment of PNMC increased expression of the pro-apoptotic protein Bax and decreased expression of the anti-apoptotic protein Bcl-XL in germ cells.In addition,testicular caspase-3 activity was significantly up-regulated and germ cell apoptosis was significantly increased in the PNMC-treated mice.In contrast,combined administration of quercetin at 75 mg/kg significantly attenuated PNMC-induced testicular toxicity.These results indicate that the antioxidant quercetin displays a remarkable protective effect on PNMC-induced oxidative damage in mouse testes and may represent an efficient supplement to attenuate reproductive toxicity by environmental toxicants to ensure healthy sperm production.
文摘Here,Ag_2S nanoparticles on reduced graphene oxide(Ag_2S NPs/RGO) nanocomposites with relatively good distribution are synthesized for the first time by conversing Ag NPs/RGO to Ag_2S NPs/RGO via a facile hydrothermal sulfurization method.As an noval catalyst for the reduction of 4-nitrophenol(4-NP),it only takes 5 min for Ag_2S NPs/RGO to reduce 98% of 4-NP,and the rate constant of the composites is almost 13 times higher than that of Ag NPs/RGO composites.The high catalytic activity of Ag_2S NPs/RGO can be attributed to the following three reasons:(1) Like metal complex catalysts,the Ag_2S NPs is also rich with metal center Ag(δ^+),with pendant base S(δ) close to it,and thus the Ag and basic S function as the electron-acceptor and proton-acceptor centers,respectively,which facilitates the catalyst reaction;(2)RGO features the high adsorption ability toward 4-NP which provides a high concentration of 4-NP near the Ag_2S NPs;and(3) electron transfer from RGO to Ag_2S NPs,facilitating the uptake of electrons by 4-NP molecules.
基金financial support from Taif University Researchers Supporting Project number (TURSP-2020/135),Taif University,Taif,Saudi Arabia。
文摘Active new ceria-promoted platinum supported on ZSM-5 catalysts were prepared and characterized by X-ray diffraction(XRD),Fourier transform infrared spectra(FTIR),transform electron microscopy(TEM),temperature programmed desorption(TPD),and FTIR of CO adsorption.The samples were prepared by the incipient wetness impregnation method and calcined at 500℃.The XRD patterns and FTIR spectra prove that the zeolite framework is kept unaltered after metal loadings.TEM images prove the presence of Pt nanoparticles with particle size starting from 14 to 27 nm.The FTIR data suggest the formation of Pt-O-Ce linkage.In-situ FTIR of CO adsorption over reduced samples proves the presence of Pt~0 only,and no Pt^(n+)-CO species are detected.The prepared catalysts were tested in both oxidation reaction(CO oxidation) in the gas phase and in reduction reaction(4-nitrophenol reduction) in the aqueous medium.Firstly,CO oxidation by O_(2) results in the formation of a CO_(2) peak at 2347 cm^(-1) as the only CO oxidation product in the studied frequency range.The intensity of the CO_(2) peak increases after the addition of Ce,and it is 4 times higher in Pt_(1) Ce_(0.5)ZSM-5 than that in the Ce-free sample.According to the FTIR data and previous reports,the increase in the catalytic activity may be due to the formation of Pt-O-Ce linkage.Secondly,Ce-promoted Pt_(1) ZSM5 also exhibits enhanced catalytic activity towards the reduction of 4-nitrophenol to 4-aminophenol by NaBH_(4) in the aqueous medium.The first-order rate constant of the reduction increases ≈13 times after incorporating equal ratios of Pt and Ce(Pt_(1) Ce_(1)ZSM-5),and the activation energy(E_(a)) decreases to 40% of that in the reaction over Pt_(1) ZSM-5.
基金funded by the National Natural Science Foundation of China(No.21776286).
文摘Generating heterophase structures in nanomaterials,e.g.,heterophase metal nanocrystals,is an effective way to tune their physicochemical properties because of their high-energy nature and unique electronic environment of the generated interfaces.However,the direct synthesis of heterophase metal nanocrystals remains a great challenge due to their unstable nature.Herein,we report the in situar direct synthesis of heterophase Ni nanocrystals on graphene.The heterostructure of face-centered cubic(fee)and hexagonal close-packed(hep)phase was generated via the epitaxial growth of hep Ni and the partial transformation of fee Ni and stabilized by the anchoring effect of graphene toward fee Ni nanocrystal and the preferential adsorption of surfactant polyethylenimine(PEI)toward epitaxial hep Ni.Comparing with the fee Ni nanocrystals grown on graphene,the heterophase(fcc/hcp)Ni nanocrystals in situ grown on graphene showed a greatly improved catalytic activity and reusability in 4-nitrophenol(4-NP)reduction to 4-aminophenol(4-AP).The measured apparent rate constant and the activity parameter were 2.958 min^(-1) and 102 min^(-1)·mg^(-1),respectively,higher than that of the best reported non-noble metal catalysts and most noble metal catalysts.The control experiments and density functional theory calculations reveal that the interface of the fee and hep phases enhances the adsorption of substrate 4-NP and thus facilitates the reaction kinetics.This work proves the novel idea for the rational design of heterophase metal nanocrystals by employing the synergistic effect of surfactant and support,and also the potential of creating the heterostructure for enhancing their catalytic reactivity.
基金This work was supported by the National Natural Science Foundation of China(Nos.21790052,21805207,and 21931007)the“111”Project of China(No.D17003).
文摘The fabrication of highly active and easily recyclable Pd-based catalyst is meaningful for their practical application.Herein,a Pd-based dip-catalyst(Pd@Pyr-GDY)is fabricated on graphdiyne(Pyr-GDY)grown on copper foam,and applied in the reduction of nitroarenes.Specially,the as-formed Pd@Pyr-GDY shows good catalytic performance toward the reduction of 4-nitrophenol(4-NP)to 4-aminophenol(4-AP)by NaBH4 with a rate constant k value of 3.84 min^(−1),which is 12-fold higher than that of the commercial Pd/C.More importantly,Pd@Pyr-GDY could be easily and rapidly recovery from the reaction medium and no distinct inactivation was found after six cycles of the reaction.This work presents an easy way to design an efficient and easily recyclable Pd-based catalyst for practical use.
