Porous metal nanostructures exhibit excellent catalytic properties due to their high surface-to-volume ratios and abundant catalytic active sites. However, it is still challenging to control nanopores density and stru...Porous metal nanostructures exhibit excellent catalytic properties due to their high surface-to-volume ratios and abundant catalytic active sites. However, it is still challenging to control nanopores density and structural features in a facile route and the preparation of porous alloy nanorods for catalytic application has not been well explored. In this work, we demonstrate a synthetic strategy to fabricate highly porous Au–Ag alloy nanorods(P-Au Ag NRs) by critically dealloying Ag atoms from homogeneous solid Au–Ag alloy nanorods(Au Ag NRs). Combining the merits of the tunable plasmonic properties of noble metal nanorods, excellent stabilities of alloys, and superior catalytic activities of porous structures, we use the P-Au Ag NRs as a Raman probe for the in situ monitoring of the catalytic oxidation of 3,3',5,5' tetramethylbenzidine(TMB) and reduction of 4-nitrothiophenol(4-NTP). We also compare their compositiondependent catalytic activities. The results show that P-Au Ag NRs possess superior chemical stability and higher catalytic activity than those of core-shell structures due to synergistic structural and chemical mechanisms. This strategy provides a predictive design approach for the next-generation alloy catalysts with high-performance.展开更多
The congruent tri-doped Mg:Mn:Fe:LiNbO 3 crystal has been grown by Czochralski method. Some crystal samples are reduced in Li 2CO 3 powder at 500 ℃ for 24 hours or oxidized for 10 hours at 1100 ℃ in Nb 2O 5 powder. ...The congruent tri-doped Mg:Mn:Fe:LiNbO 3 crystal has been grown by Czochralski method. Some crystal samples are reduced in Li 2CO 3 powder at 500 ℃ for 24 hours or oxidized for 10 hours at 1100 ℃ in Nb 2O 5 powder. Compared with As-grown Mg:Mn:Fe:LiNbO 3, the absorption edge in UV-Vis. absorption spectrum of the oxidized sample and the reduced shifts to the violet and the red, respectively. Reduction increases the absorption of crystals in visible light region. In two-wave coupling experiments, the writing time, maximum diffraction efficiency and the erasure time of crystal samples in the same conditions are determined. The results indicate that oxidation and reduction disposing has great effect on the holographic recording properties of these crystals. The reduced crystal exhibits the fastest response time of 160 s among the crystal series. The mechanism of post-disposing effect on the holographic recording properties of Mg:Mn:Fe:LiNbO 3 crystals are investigated.展开更多
Sustainable detoxification and advanced treatment of toxic organic pollutants(TOPs)in wastewater are essential for water reclamation and ecosystem security.Although biological treatment is a low-carbon and eco-friendl...Sustainable detoxification and advanced treatment of toxic organic pollutants(TOPs)in wastewater are essential for water reclamation and ecosystem security.Although biological treatment is a low-carbon and eco-friendly approach for TOPs degradation,its effectiveness is often limited by the high toxicity and recalcitrance of TOPs.Oxidative and reductive reactions can degrade TOPs according to their intrinsic redox potentials.However,conventional biological or chemical oxidation treatment often fails to efficiently or purposefully cleave key functional groups,which leads to unsatisfactory performance of biological reactions or excessive chemical oxidation costs.This perspective proposes redox regulation as a strategy to moderately catalyse the oxidation or reduction of TOPs and thereby generate low toxicity and increased biodegradable intermediates,which will improve subsequent biological treatment.We summarize strong redox regulation techniques,including advanced oxidation and reduction processes,and weak redox regulation through low-energy electrical potential,along with the corresponding mechanisms and applications.Additionally,we explore the integration of redox regulation with biological treatment,either in a sequential mode or in situ.This study emphasizes the need for future research to focus on targeted and durable catalytic detoxification processes and to optimize balancing the carbon footprint,process control,operational efficiency,and economic feasibility.By integrating chemical reactions with microbial metabolism,redox regulation has the potential to transform wastewater treatment from isolated process optimization to a holistic approach.This perspective advocates for innovation of conventional wastewater detoxification technologies to achieve sustainable water purification and ecological risk control.展开更多
Key intermediate bis[2-amino-4,5-(15-crown-5)phenyl]diselenide was obtained by the convenient redox method. Crown-ether type host molecule containing Se-Se bond 2,11-dioxo-4,5:8,9-di(benzo[4',5']-15-crown-5)-6...Key intermediate bis[2-amino-4,5-(15-crown-5)phenyl]diselenide was obtained by the convenient redox method. Crown-ether type host molecule containing Se-Se bond 2,11-dioxo-4,5:8,9-di(benzo[4',5']-15-crown-5)-6,7-diselena-3,10,16-triazabicyclo[10,3,1]hexadeca-1(16), 4, 8, 12, 14-pentaene was synthesized with high dillution technique.展开更多
The NH3 oxidation and reduction process are experimentally and kinetically studied in this paper. It is found that NH3 has contributions not only to N2O formation, but also to N2O destruction in certain conditions. Th...The NH3 oxidation and reduction process are experimentally and kinetically studied in this paper. It is found that NH3 has contributions not only to N2O formation, but also to N2O destruction in certain conditions. The main product of homogeneous NH3 oxidation is found to be NO rather than N2O,but some bed materials and sulphur sorbents have catalytic contributions to N2O formation from NH3oxidation. In reduction atmosphere, NH3 can promote the KC destruction. It is deduced that the ammonia injection into fluidized bed coal combustion fine gas can decrease both Nox and N3O emissions.The ammonia injection process is kinetically simulated in this study, and the reduction rates of NOX and N2O are found to depend on eemperatue, O2 concentration, initial NOx and N2O concentrations,and amount of injected ammonia.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 11774171, 21805137 and11874220)the Fundamental Research Funds for the Central Universities (No. NT2020019)+1 种基金the Open Fund of Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education(No. INMD-2020M03)the Priority Academic Program Development of Jiangsu Higher Education Institutions (No. KYZZ16-0165)。
文摘Porous metal nanostructures exhibit excellent catalytic properties due to their high surface-to-volume ratios and abundant catalytic active sites. However, it is still challenging to control nanopores density and structural features in a facile route and the preparation of porous alloy nanorods for catalytic application has not been well explored. In this work, we demonstrate a synthetic strategy to fabricate highly porous Au–Ag alloy nanorods(P-Au Ag NRs) by critically dealloying Ag atoms from homogeneous solid Au–Ag alloy nanorods(Au Ag NRs). Combining the merits of the tunable plasmonic properties of noble metal nanorods, excellent stabilities of alloys, and superior catalytic activities of porous structures, we use the P-Au Ag NRs as a Raman probe for the in situ monitoring of the catalytic oxidation of 3,3',5,5' tetramethylbenzidine(TMB) and reduction of 4-nitrothiophenol(4-NTP). We also compare their compositiondependent catalytic activities. The results show that P-Au Ag NRs possess superior chemical stability and higher catalytic activity than those of core-shell structures due to synergistic structural and chemical mechanisms. This strategy provides a predictive design approach for the next-generation alloy catalysts with high-performance.
基金The subject has been supported by Chinese National Advanced Technology 863 Project(Grant No.8632001AA31304)Chinese National 973 Project(Grant No.G19990330).
文摘The congruent tri-doped Mg:Mn:Fe:LiNbO 3 crystal has been grown by Czochralski method. Some crystal samples are reduced in Li 2CO 3 powder at 500 ℃ for 24 hours or oxidized for 10 hours at 1100 ℃ in Nb 2O 5 powder. Compared with As-grown Mg:Mn:Fe:LiNbO 3, the absorption edge in UV-Vis. absorption spectrum of the oxidized sample and the reduced shifts to the violet and the red, respectively. Reduction increases the absorption of crystals in visible light region. In two-wave coupling experiments, the writing time, maximum diffraction efficiency and the erasure time of crystal samples in the same conditions are determined. The results indicate that oxidation and reduction disposing has great effect on the holographic recording properties of these crystals. The reduced crystal exhibits the fastest response time of 160 s among the crystal series. The mechanism of post-disposing effect on the holographic recording properties of Mg:Mn:Fe:LiNbO 3 crystals are investigated.
基金supported by the National Natural Science Foundation of China(Grant No.52321005,52293443,and 52270067)the Shenzhen Science and Technology Program(Grant No.KQTD20190929172630447).
文摘Sustainable detoxification and advanced treatment of toxic organic pollutants(TOPs)in wastewater are essential for water reclamation and ecosystem security.Although biological treatment is a low-carbon and eco-friendly approach for TOPs degradation,its effectiveness is often limited by the high toxicity and recalcitrance of TOPs.Oxidative and reductive reactions can degrade TOPs according to their intrinsic redox potentials.However,conventional biological or chemical oxidation treatment often fails to efficiently or purposefully cleave key functional groups,which leads to unsatisfactory performance of biological reactions or excessive chemical oxidation costs.This perspective proposes redox regulation as a strategy to moderately catalyse the oxidation or reduction of TOPs and thereby generate low toxicity and increased biodegradable intermediates,which will improve subsequent biological treatment.We summarize strong redox regulation techniques,including advanced oxidation and reduction processes,and weak redox regulation through low-energy electrical potential,along with the corresponding mechanisms and applications.Additionally,we explore the integration of redox regulation with biological treatment,either in a sequential mode or in situ.This study emphasizes the need for future research to focus on targeted and durable catalytic detoxification processes and to optimize balancing the carbon footprint,process control,operational efficiency,and economic feasibility.By integrating chemical reactions with microbial metabolism,redox regulation has the potential to transform wastewater treatment from isolated process optimization to a holistic approach.This perspective advocates for innovation of conventional wastewater detoxification technologies to achieve sustainable water purification and ecological risk control.
文摘Key intermediate bis[2-amino-4,5-(15-crown-5)phenyl]diselenide was obtained by the convenient redox method. Crown-ether type host molecule containing Se-Se bond 2,11-dioxo-4,5:8,9-di(benzo[4',5']-15-crown-5)-6,7-diselena-3,10,16-triazabicyclo[10,3,1]hexadeca-1(16), 4, 8, 12, 14-pentaene was synthesized with high dillution technique.
文摘The NH3 oxidation and reduction process are experimentally and kinetically studied in this paper. It is found that NH3 has contributions not only to N2O formation, but also to N2O destruction in certain conditions. The main product of homogeneous NH3 oxidation is found to be NO rather than N2O,but some bed materials and sulphur sorbents have catalytic contributions to N2O formation from NH3oxidation. In reduction atmosphere, NH3 can promote the KC destruction. It is deduced that the ammonia injection into fluidized bed coal combustion fine gas can decrease both Nox and N3O emissions.The ammonia injection process is kinetically simulated in this study, and the reduction rates of NOX and N2O are found to depend on eemperatue, O2 concentration, initial NOx and N2O concentrations,and amount of injected ammonia.
