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
The scarcity and weak durability of metal,especially precious metal catalysts are big obstacles for their large-scale application in many reactions.The state-of-the-art of the catalytic science prefers such type of ca...The scarcity and weak durability of metal,especially precious metal catalysts are big obstacles for their large-scale application in many reactions.The state-of-the-art of the catalytic science prefers such type of catalysts,which can replace metal-based catalysts to alleviate energy and environmental crises and exhibit catalytic performance comparable to or even exceeding these metal catalysts.Herein,we report that N-doped porous carbon(NKC)derived from cheap and abundant radish can be employed as versatile and efficient bifunctional catalysts in both the catalytic reduction of 4-nitrophenol(NRR)and oxidation of styrene(SOR).The series of NKC catalysts were prepared with a simple and facile one-pot strategy by coupling the N-doping,carbonization and KOH activation processes.These catalysts show hierarchical porosity,with the specific surface area,total pore volume and N-doping content ranging from 918.9-3062.7 m^2 g^-1,1.01-2.04 cm^3 g^-1 and 1.29-15.3 at%,respectively.Interestingly,our finding suggests that the catalytic performance is not directly related to these parameters but correlates positively with the content of graphitic N dopants,which is the dominant contributor for impelling both the NRR and SOR.Another intriguing finding is that for both reactions,the optimal catalyst was found to be the NKC-3-800 which possesses the highest graphitic N content of 3.13 at%.In addition,to gain insight into the catalytic behavior,analyses of kinetics and thermodynamics were performed,and the catalytic mechanisms were postulated.This work paves the way for the construction of biomass-derived N-doped carbon catalysts for bi-or even multi-functional applications in various organic reactions.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
The reduction of 4-nitrophenol catalyzed by nitroreductase in the presence of NADH was investigated in this paper. 4-Amino- phenol and 4-hydroxylamino-phenol were found in the reductive products. The relationship betw...The reduction of 4-nitrophenol catalyzed by nitroreductase in the presence of NADH was investigated in this paper. 4-Amino- phenol and 4-hydroxylamino-phenol were found in the reductive products. The relationship between reaction time and the reductive ratio were studied. The similar reducing ratios of 4-nitrophenol were obtained under aerobic and anaerobic conditions. The results indicated that an oxygen-insensitive reaction was proceeded in the reduction of 4-nitrophenol and nitroreductase was an oxygeninsensitive enzyme. The reductive products of 4-nitrophenol were determined by HPLC and MS.展开更多
Palladium-supported cobalt hydroxide(Co(OH)_(2)-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol.For the preparation of Co(OH)2-Pd,Pd nanoparticles we...Palladium-supported cobalt hydroxide(Co(OH)_(2)-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol.For the preparation of Co(OH)2-Pd,Pd nanoparticles were anchored on the Co(OH)_(2) nanoplates after the reduction of Na;PdCl;by ascorbic acid in the absence of a stabilizer at room temperature.The observations under transmission and scanning electron microscopy reveal that Pd nanoparticles with a size of 2-5 nm are uniformly dispersed on the surface of the Co(OH)_(2) nanoplates.In catalytic test,the conversion of 4-nitrophenol to 4-aminophenol is completed within 6 min in the presence of Co(OH)_(2)-Pd(1000) nanoplates with2.18 at.% Pd,and the corresponding kinetic constant is 0.0089 s;in the first test.The catalyst retains relatively high activity after several cycles.The results demonstrate that the Co(OH)_(2)-Pd(1000) nanoplates exhibit high catalytic activity toward the reduction of 4-nitrophenol in the presence of NaBH;.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
Highly dispersed Pd/N-doped carbon dots(Pd/NCDs)were successfully immobilized in the mesoporous channels of amino-functionalized dendritic mesoporous silica nanospheres(NMS).The synthesized Pd/NCDs@NMS catalyst exhibi...Highly dispersed Pd/N-doped carbon dots(Pd/NCDs)were successfully immobilized in the mesoporous channels of amino-functionalized dendritic mesoporous silica nanospheres(NMS).The synthesized Pd/NCDs@NMS catalyst exhibits outstanding performance in the catalytic reduction of 4-nitrophenol(4-NP),achieving a turnover frequency of 1461.8 mol·molPd^(-1)·h^(-1),with the conversion rate remaining above 80%after 11 cycles.Experiments and density functional theory calculations reveal that the NCDs significantly affect the electronic structure of Pd nanoparticles,leading to changes in the energy barriers for the adsorption of 4-NP at the Pd sites and the conversion of 4-NP reaction intermediates,which is a key factor contributing to the catalytic performance.This study offers a new strategy for synthesizing carbon-dot-modified metal-based catalysts.展开更多
To realize economical and effective removal of hazardous 4-nitrophenol from the environment,we developed an easily recyclable ZnO nanowire array decorated with Cu nanoparticles.Its salix argyracea-shaped structure not...To realize economical and effective removal of hazardous 4-nitrophenol from the environment,we developed an easily recyclable ZnO nanowire array decorated with Cu nanoparticles.Its salix argyracea-shaped structure not only provides a platform to achieve stable and good dispersion of Cu nanoparticles,but also offers a great deal of catalytically active sites.The density functional theory calculations reveal that ZnO and Cu have a very beneficial synergistic effect on their catalytic capability.This synergy is ascribed to the electronic localization occurring at ZnO/Cu interface,which helps improve Cu nanoparticle’s ability to adsorb electro-negatively 4-nitrophenolate ions and to capture hydrogen radicals,thereby accelerating the hydrogen transfer from metal hydride complex to 4-nitrophenol.Benefiting from these characteristics,it exhibits high efficiency and reusability towards the catalytic reduction of waste 4-nitrophenol to valuable 4-aminophenol with a rate constant of 43.02×10^(-3)s^(-1)and an average conversion of 96.5%in 90 s during 10 cycles.This activity is superior to that of most reported noble-or non-noble-metal powder,bulk,coating,and array catalysts,indicating its competitive advantages in cost and efficiency,as well as enticing application prospects.展开更多
An“on–off–on”fluorescence sensor was designed for rapidly and consecutively detecting 4-nitrophenol and cerium(IV)without the use of any labeling materials.The yellow carbon dots were synthesized by a simple one-s...An“on–off–on”fluorescence sensor was designed for rapidly and consecutively detecting 4-nitrophenol and cerium(IV)without the use of any labeling materials.The yellow carbon dots were synthesized by a simple one-step hydrothermal approach,and various techniques were applied to investigate the morphology,structure,and optical properties of the carbon dots.Under the optimal experimental conditions,4-nitrophenol rapidly quenched the fluorescence of carbon dots as a result of the inner filter eff ect(IFE).The fluorescence intensity of carbon dots was linear with the concentration of 4-nitrophenol(1–150μmol/L)and the limit of detection was 0.32μmol/L.The fluorescence was gradually recovered as the cerium(IV)concentration(0.5–100μmol/L)increased in CDs/4-NP,and the limit of detection was 0.16μmol/L.The sensor showed good selectivity and demonstrated high accuracy for the analysis of 4-nitrophenol and cerium(IV)in actual water samples.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.
文摘The scarcity and weak durability of metal,especially precious metal catalysts are big obstacles for their large-scale application in many reactions.The state-of-the-art of the catalytic science prefers such type of catalysts,which can replace metal-based catalysts to alleviate energy and environmental crises and exhibit catalytic performance comparable to or even exceeding these metal catalysts.Herein,we report that N-doped porous carbon(NKC)derived from cheap and abundant radish can be employed as versatile and efficient bifunctional catalysts in both the catalytic reduction of 4-nitrophenol(NRR)and oxidation of styrene(SOR).The series of NKC catalysts were prepared with a simple and facile one-pot strategy by coupling the N-doping,carbonization and KOH activation processes.These catalysts show hierarchical porosity,with the specific surface area,total pore volume and N-doping content ranging from 918.9-3062.7 m^2 g^-1,1.01-2.04 cm^3 g^-1 and 1.29-15.3 at%,respectively.Interestingly,our finding suggests that the catalytic performance is not directly related to these parameters but correlates positively with the content of graphitic N dopants,which is the dominant contributor for impelling both the NRR and SOR.Another intriguing finding is that for both reactions,the optimal catalyst was found to be the NKC-3-800 which possesses the highest graphitic N content of 3.13 at%.In addition,to gain insight into the catalytic behavior,analyses of kinetics and thermodynamics were performed,and the catalytic mechanisms were postulated.This work paves the way for the construction of biomass-derived N-doped carbon catalysts for bi-or even multi-functional applications in various organic reactions.
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.
文摘The reduction of 4-nitrophenol catalyzed by nitroreductase in the presence of NADH was investigated in this paper. 4-Amino- phenol and 4-hydroxylamino-phenol were found in the reductive products. The relationship between reaction time and the reductive ratio were studied. The similar reducing ratios of 4-nitrophenol were obtained under aerobic and anaerobic conditions. The results indicated that an oxygen-insensitive reaction was proceeded in the reduction of 4-nitrophenol and nitroreductase was an oxygeninsensitive enzyme. The reductive products of 4-nitrophenol were determined by HPLC and MS.
基金the financial supports from the National Natural Science Foundation of China (Nos. 51974116, 51874128)the Science Foundation of Hunan Province, China (Nos. 2020JJ4273, 2020JJ5130)。
文摘Palladium-supported cobalt hydroxide(Co(OH)_(2)-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol.For the preparation of Co(OH)2-Pd,Pd nanoparticles were anchored on the Co(OH)_(2) nanoplates after the reduction of Na;PdCl;by ascorbic acid in the absence of a stabilizer at room temperature.The observations under transmission and scanning electron microscopy reveal that Pd nanoparticles with a size of 2-5 nm are uniformly dispersed on the surface of the Co(OH)_(2) nanoplates.In catalytic test,the conversion of 4-nitrophenol to 4-aminophenol is completed within 6 min in the presence of Co(OH)_(2)-Pd(1000) nanoplates with2.18 at.% Pd,and the corresponding kinetic constant is 0.0089 s;in the first test.The catalyst retains relatively high activity after several cycles.The results demonstrate that the Co(OH)_(2)-Pd(1000) nanoplates exhibit high catalytic activity toward the reduction of 4-nitrophenol in the presence of NaBH;.
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 National Key R&D Program of China(No.2022YFA1503501)the National Natural Science Foundation of China(Nos.22088101 and U21A20329)+2 种基金Program of Shanghai Academic Research Leader(No.21XD1420800)Shanghai Pilot Program for Basic Research-FuDan University 21TQ1400100(21TQ008)“Shuguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.22SG02).
文摘Highly dispersed Pd/N-doped carbon dots(Pd/NCDs)were successfully immobilized in the mesoporous channels of amino-functionalized dendritic mesoporous silica nanospheres(NMS).The synthesized Pd/NCDs@NMS catalyst exhibits outstanding performance in the catalytic reduction of 4-nitrophenol(4-NP),achieving a turnover frequency of 1461.8 mol·molPd^(-1)·h^(-1),with the conversion rate remaining above 80%after 11 cycles.Experiments and density functional theory calculations reveal that the NCDs significantly affect the electronic structure of Pd nanoparticles,leading to changes in the energy barriers for the adsorption of 4-NP at the Pd sites and the conversion of 4-NP reaction intermediates,which is a key factor contributing to the catalytic performance.This study offers a new strategy for synthesizing carbon-dot-modified metal-based catalysts.
基金the financial support from the National Natural Science Foundation of China(51804132 and 32101059)the Natural Science Foundation of Hebei Province(No.B2022202057)
文摘To realize economical and effective removal of hazardous 4-nitrophenol from the environment,we developed an easily recyclable ZnO nanowire array decorated with Cu nanoparticles.Its salix argyracea-shaped structure not only provides a platform to achieve stable and good dispersion of Cu nanoparticles,but also offers a great deal of catalytically active sites.The density functional theory calculations reveal that ZnO and Cu have a very beneficial synergistic effect on their catalytic capability.This synergy is ascribed to the electronic localization occurring at ZnO/Cu interface,which helps improve Cu nanoparticle’s ability to adsorb electro-negatively 4-nitrophenolate ions and to capture hydrogen radicals,thereby accelerating the hydrogen transfer from metal hydride complex to 4-nitrophenol.Benefiting from these characteristics,it exhibits high efficiency and reusability towards the catalytic reduction of waste 4-nitrophenol to valuable 4-aminophenol with a rate constant of 43.02×10^(-3)s^(-1)and an average conversion of 96.5%in 90 s during 10 cycles.This activity is superior to that of most reported noble-or non-noble-metal powder,bulk,coating,and array catalysts,indicating its competitive advantages in cost and efficiency,as well as enticing application prospects.
基金National Natural Science Foundation of China(22274096 and 22272119)the Shanghai Municipal Science and Technology Major Project(2021SHZDZX0100)+2 种基金the Science and Technology Committee of Shanghai Municipality(2022-4-ZD-03)the Shanghai Pilot Program for Basic Researchthe Fundamental Research Funds for the Central Universities。
文摘An“on–off–on”fluorescence sensor was designed for rapidly and consecutively detecting 4-nitrophenol and cerium(IV)without the use of any labeling materials.The yellow carbon dots were synthesized by a simple one-step hydrothermal approach,and various techniques were applied to investigate the morphology,structure,and optical properties of the carbon dots.Under the optimal experimental conditions,4-nitrophenol rapidly quenched the fluorescence of carbon dots as a result of the inner filter eff ect(IFE).The fluorescence intensity of carbon dots was linear with the concentration of 4-nitrophenol(1–150μmol/L)and the limit of detection was 0.32μmol/L.The fluorescence was gradually recovered as the cerium(IV)concentration(0.5–100μmol/L)increased in CDs/4-NP,and the limit of detection was 0.16μmol/L.The sensor showed good selectivity and demonstrated high accuracy for the analysis of 4-nitrophenol and cerium(IV)in actual water samples.
