To modify the thermodynamics and kinetic performance of magnesium hydride(MgH_(2))for solid-state hydrogen storage,Ni_(3)V_(2)O_(8)-rGO(rGO represents reduced graphene oxide)and Ni_(3)V_(2)O_(8)nanocomposites were pre...To modify the thermodynamics and kinetic performance of magnesium hydride(MgH_(2))for solid-state hydrogen storage,Ni_(3)V_(2)O_(8)-rGO(rGO represents reduced graphene oxide)and Ni_(3)V_(2)O_(8)nanocomposites were prepared by hydrothermal and subsequent heat treatment.The beginning hydrogen desorption temperature of 7 wt.%Ni_(3)V_(2)O_(8)-rGO modified MgH_(2)was reduced to 208℃,while the additive-free MgH_(2)and 7 wt.%Ni_(3)V_(2)O_(8)doped MgH_(2)appeared to discharge hydrogen at 340 and 226℃,respectively.A charging capacity of about 4.7 wt.%H_(2)for MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO was achieved at 125℃ in 10 min,while the dehydrogenated MgH_(2)took 60 min to absorb only 4.6 wt.%H_(2)at 215℃.The microstructure analysis confirmed that the in-situ generated Mg_(2)Ni/Mg_(2)N_(i)H_(4) and metallic V contributed significantly to the enhanced performance of MgH_(2).In addition,the presence of rGO in the MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO composite reduced particle aggregation tendency of Mg/MgH_(2),leading to improving the cyclic stability of MgH_(2)during 20 cycles.展开更多
Improving catalytic performance is a yet still challenge in thermal catalytic oxidation.Herein,uniform mesoporous MnO_(2) nanospheresupported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO_(2) ...Improving catalytic performance is a yet still challenge in thermal catalytic oxidation.Herein,uniform mesoporous MnO_(2) nanospheresupported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO_(2) template strategy for the total catalytic degradation of volatile organic compounds at low temperature.The introduction of mesopores into the MnO_(2) support induces a large specific surface area and pore size,thus providing numerous accessible active sites and enhanced diffusion properties.Moreover,the addition of a secondary noble metal can adjust the O_(ads)/O_(latt) molar ratios,resulting in high catalytic activity.Among them,the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 mL g^(-1) h^(-1),reaching 100%toluene oxidation at 175℃ with a lower activation energy(57.0 kJ mol^(-1))than the corresponding monometallic Pt or non-Pt-based catalysts(93.8 kJ mol^(-1) and 214.2 kJ mol^(-1)).Our findings demonstrate that the uniform mesoporous MnO_(2) nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.展开更多
In the present work, a series of Pt-based catalysts, alloyed with a second metal, i.e., Re, Sn, Er, La, and Y, and supported on activated carbon, ordered mesoporous carbon, N-doped mesoporous carbon or reduced graphen...In the present work, a series of Pt-based catalysts, alloyed with a second metal, i.e., Re, Sn, Er, La, and Y, and supported on activated carbon, ordered mesoporous carbon, N-doped mesoporous carbon or reduced graphene oxide(rGO), have been developed for selective hydrogenation of cinnamaldehyde to cinnamylalcohol. Re and rGO were proved to be the most favorable metal dopant and catalyst support, respectively. Pt_(50) Re_(50)/rGO showed the highest cinnamylalcohol selectivity of 89% with 94% conversion of cinnamaldehyde at the reaction conditions of 120 °C, 2.0 MPaH_2 and 4 h.展开更多
Highly sensitive gas sensors with remarkably low detection limits are attractive for diverse practical application fields including real-time environmental monitoring,exhaled breath diagnosis,and food freshness analys...Highly sensitive gas sensors with remarkably low detection limits are attractive for diverse practical application fields including real-time environmental monitoring,exhaled breath diagnosis,and food freshness analysis.Among various chemiresistive sensing materials,noble metal-decorated semiconducting metal oxides(SMOs)have currently aroused extensive attention by virtue of the unique electronic and catalytic properties of noble metals.This review highlights the research progress on the designs and applications of different noble metal-decorated SMOs with diverse nanostructures(e.g.,nanoparticles,nanowires,nanorods,nanosheets,nanoflowers,and microspheres)for high-performance gas sensors with higher response,faster response/recovery speed,lower operating temperature,and ultra-low detection limits.The key topics include Pt,Pd,Au,other noble metals(e.g.,Ag,Ru,and Rh.),and bimetals-decorated SMOs containing ZnO,SnO_(2),WO_(3),other SMOs(e.g.,In_(2)O_(3),Fe_(2)O_(3),and CuO),and heterostructured SMOs.In addition to conventional devices,the innovative applications like photo-assisted room temperature gas sensors and mechanically flexible smart wearable devices are also discussed.Moreover,the relevant mechanisms for the sensing performance improvement caused by noble metal decoration,including the electronic sensitization effect and the chemical sensitization effect,have also been summarized in detail.Finally,major challenges and future perspectives towards noble metal-decorated SMOs-based chemiresistive gas sensors are proposed.展开更多
In the present work, a novel heterogeneous photo-Fenton catalyst was prepared by iron and cerium pillared bentonite. The catalyst Fe-Ce/bentonite was characterized by X-ray diffraction （XRD）, X-ray fluorescence （XR...In the present work, a novel heterogeneous photo-Fenton catalyst was prepared by iron and cerium pillared bentonite. The catalyst Fe-Ce/bentonite was characterized by X-ray diffraction （XRD）, X-ray fluorescence （XRF）, Brunauer-Emmett-Teller （BET） and scanning electron microscopy （SEM） methods. It is found that Fe and Ce intercalate into the silicate layers of bentonite successfully. Tetracycline was removed by heterogeneous photo-Fenton reaction using the catalyst in this work. The effects of different reaction systems, hydrogen peroxide concentration, initial pH, catalyst dosage, UV power and introduction of different anions on degradation were investigated in details. The stability of catalyst was investigated through recycling experiment. The results show that removal rate of tetracycline is 98.13% under the conditions of 15 mmol/L H202, 0.50 g/L catalyst dosage, initial pH 3.0, 11 W UV lamp power and 60 min reaction time. However, the removal rate decreases after adding some anions. The hydroxyl radical plays an important role in heterogeneous photo-assisted Fenton degradation of tetracycline. The catalyst is very stable and can be recycled many times.展开更多
This study highlights introducing the rare earth metal cerium(Ce(Ⅳ))into the structure of magnetite(Fe_(3)O_(4))to achieve enhanced adsorptive properties for the removal of chromium(Cr(VI))from an aqueous medium.Diff...This study highlights introducing the rare earth metal cerium(Ce(Ⅳ))into the structure of magnetite(Fe_(3)O_(4))to achieve enhanced adsorptive properties for the removal of chromium(Cr(VI))from an aqueous medium.Different ratios of Ce(Ⅳ)were introduced into the iron oxide matrix,termed FeCe-5,FeCe-10,and FeCe-20.Their numerical values correspond to the nominal content of the dopant element added to the synthesis medium.The solid materials were characterized for morphology and chemical structure,and N_(2)physical adsorption/desorption measurements were performed.The solid materials doped with Ce(IV)have a high surface area compared to Fe_(3)O_(4),and the solid material with the highest content of the dopant ion(Ce(IV))has a 4-fold greater surface area.This increase in the dopant content in the iron oxide structure leads to a total chromium removal of 93.3%.Isotherms studies on the solid materials show that chromium adsorption follows the Langmuir model.The adsorption capacity to Fe_(3)O_(4)is 12.59 mg/g and FeCe-10 is 22.49 mg/g at 35℃.By fitting the kinetic and isothermal models,it is found that for the Fe_(3)O_(4)and FeCe-10 materials Cr(VI)removal occurs in very different ways,attributed to the different surface areas and compositions of the oxide,with the formation of the goethite(α-FeOOH)phase.The FeCe-10reuse process was performed and the removal capacity the Cr(VI)is reduced after the first cycle.This result is attributed to a strong and irreversible adsorption of Cr(VI)on the FeCe-10.展开更多
The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared betw...The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared between the Al22 Si and ZL102 bimetal.The average bonding strength of bimetal with intermittent oxide film interface was about 89.3MPa,which is higher than that of the bimetal fabricated by zinc coating method（about 76.3MPa）.During the process of extrusion,the oxidation film was extruded to crush and the metal was extruded through the micro-cracks of the oxidation film,then the two surfaces were joined together.Altogether,the results showed that extrusion at near-eutectic temperature is favorable for achieving a high-quality metallurgical bonded interface.展开更多
This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac(DCF),as compared to much slow removal of DCF by Cu(Ⅱ) or zero valent iron nanopar...This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac(DCF),as compared to much slow removal of DCF by Cu(Ⅱ) or zero valent iron nanoparticles(nZVI),respectively.Further observations on the evolution of O_(2) activation process by nano Fe/Cu bimetals was conducted stretching to the preparation phase(started by nZVI/Cu2+).Interesting breakpoints we re observed with obvious sudden increase in the DCF degradation efficiency and decrease in solution pH,as the original nZVI just consumed up to Fe(Ⅱ) and Cu(II) appeared again.It suggested that the four-electrons reaction of O_(2) and Cu-deposited nZVI would occur to generate water prior to the breakpoints,while Cu(0) and Fe(Ⅱ) would play most important role in activation of O_(2) afterwards.Through the electron spin resonance(ESR) analysis and quenching experiments.·OH was identified as the responsible reactive species.Further time-dependent quantifications in the cases of Cu(0)/Fe(Ⅱ) systems we re carried out.It was found that the ’OH accumulation was positively and linearly correlated with nCu dose,Fe(Ⅱ) consumption,and Fe(II) dose,respectively.Since either Cu(O) or Fe(Ⅱ)would be inefficient in activating oxygen to produce ·OH,a stage-evolution mechanism of O_(2) activated by nano Fe/Cu bimetals was proposed involving:(a) Rapid consumption of Fe(0) and release of Fe(Ⅱ) based on the Cu-Fe galvanic corrosion,(b) adsorption and transformation of O_(2) to O_(2)2 at the nCu surface,and(c) Fe(Ⅱ)-catalyzed activation of the adsorbed O_(2)2 to ·OH.展开更多
Creating a new low-temperature catalyst in decreasing the emission of volatile organic compounds(VOCs)has great significance under different industrial production situations.In particular,the Zr-UiO-66 is optimized by...Creating a new low-temperature catalyst in decreasing the emission of volatile organic compounds(VOCs)has great significance under different industrial production situations.In particular,the Zr-UiO-66 is optimized by different amounts of cerium,which not only enhances the physicochemical stability but also increases the number of active sites of Ce_(x)Zr_(y)UiO-66.Furthermore,the catalysts with Co_(3)O_(4)nanoparticles supported on Ce_(x)Zr_(y)UiO-66 were successfully prepared via impregnation method.In the process of toluene degradation,the Co/Ce_(1)Zr_(2)-Ui0-66 attains a 90%conversion rate at 210℃with a space velocity of 60000 mL/(g·h)and toluene concentration at 1000×10^(-6).Meanwhile,the carbon dioxide selectivity reaches 100%at 218℃.The Co/Ce_(1)Zr_(2)-UiO-66 shows great water resistance(3 vol%H_(2)O).Multiple characterization methods were used to figure out the physicochemical properties of the catalysts.It is found that the addition of an appropriate amount of cerium can enhance stability of UiO-66 and surface lattice oxygen proportion.Additionally,the stronger electron transfer between Ce^(4+)and Co^(2+)enables the Co/Ce_(1)Zr_(2)-UiO-66 to possess more active surface oxygen species and Co_(3)+cationic species in all samples.展开更多
Novel Mg O–SBA-15 supported catalysts were prepared for oxidative esterification of methacrolein(MAL) with methanol to methyl methacrylate(MMA). The Mg O–SBA-15 supports were synthesized with different magnesia load...Novel Mg O–SBA-15 supported catalysts were prepared for oxidative esterification of methacrolein(MAL) with methanol to methyl methacrylate(MMA). The Mg O–SBA-15 supports were synthesized with different magnesia loadings from different magnesium precursors and hydrochloric acid molar concentrations. The Mg O–SBA-15 supports and Pd–Pb/Mg O–SBA-15 catalysts were characterized by several analysis methods. The results revealed that the addition of Mg O improved the ordered structure of SBA-15 supports and provided surface alkalinity of SBA-15 supports. The average size of the Pd3 Pb particles on magnesia-modified Pd–Pb/Mg O–SBA-15 catalysts was smaller than that on the pure silica-based Pd–Pb/SBA-15 catalysts. The experiments on catalyst performance showed that the magnesia-modified Pd–Pb/Mg O–SBA-15 catalysts had higher activity than pure silica-based Pd–Pb/SBA-15 catalysts, showing the strong dependence of catalytic activity on the average size of active particles. The difference of activity between Pd–Pb/SBA-15 catalysts and Pd–Pb/Mg O–SBA-15 catalysts was due to the discrepant structural properties and surface alkalinity provided by Mg O, which led to the different Pd3 Pb particle sizes and then resulted in the different number of active sites. Besides magnesia loadings, other factors, such as hydrochloric acid molar concentration and magnesium precursors, had considerable influences on the catalytic activity.展开更多
Developing electrocatalysts with high performance and low cost for the oxygen evolution reaction(OER)is of great importance for fabricating renewable energy storage and conversion devices.Here,a series of boron-doped ...Developing electrocatalysts with high performance and low cost for the oxygen evolution reaction(OER)is of great importance for fabricating renewable energy storage and conversion devices.Here,a series of boron-doped graphene(BG)-supported bimetallic oxides of Co and Ni were obtained and served as OER electrocatalysts.Surprisingly,the annealed Co-Ni-Ox/BG with a Co/Ni ratio of 1:1 exhibits high performance toward oxygen evolution in alkaline electrolyte.The overpotential is only 310 mV at the current density of 10 mA cm-2,superior to many mono-metallic oxides reported before,and even comparable to the commercial RuO2.The regulation of charge distribution in bimetallic oxides and the strong synergistic coupling effects together contribute to the superior electrocatalytic performance of the Co-Ni-Ox/BG toward OER.This study also offers several effective ways to design high-performance OER electrocatalysts for water splitting.展开更多
Precisely tuning bicomponent intimacy during reactions by traditional methods remains a formidable challenge in the fabrication of highly active and stable catalysts because of the difficulty in constructing well-defi...Precisely tuning bicomponent intimacy during reactions by traditional methods remains a formidable challenge in the fabrication of highly active and stable catalysts because of the difficulty in constructing well-defined catalytic systems and the occurrence of agglomeration during assembly.To overcome these limitations,a PtRuPNiO@TiO_(x)catalyst on a Ti plate was prepared by ultrasound-assisted low-voltage plasma electrolysis.This method involves the oxidation of pure Ti metal and co-reduction of strong metals at 3000◦C,followed by sonochemical ultrasonication under ambient conditions in an aqueous solution.The intimacy of the bimetals in PtRuPNiO@TiOx is tuned,and the metal nanoparticles are uniformly distributed on the porous titania coating via strong metal-support interactions by leveraging the instantaneous high-energy input from the plasma discharge and ultrasonic irradiation.The intimacy of PtRuPNiO@TiO_(x)increases the electron density on the Pt surface.Consequently,the paired sites exhibit a high hydrogen evolution reaction activity(an overpotential of 220 mV at a current density of 10 mA cm^(−2)and Tafel slope of 186 mV dec^(−1)),excellent activity in the hydrogenation of 4-nitrophenol with a robust stability for up to 20 cycles,and the ability to contrast stated catalysts without ultrasonication and plasma electrolysis.This study facilitates industrially important reactions through synergistic chemical interactions.展开更多
The unique properties of metal oxide surfaces,crystal surfaces and defects play vital roles in biomass upgrading reactions.In this work,hierarchical porous bowl-shaped ZrO_(2)(HB-ZrO_(2))with mixed crystal phase was d...The unique properties of metal oxide surfaces,crystal surfaces and defects play vital roles in biomass upgrading reactions.In this work,hierarchical porous bowl-shaped ZrO_(2)(HB-ZrO_(2))with mixed crystal phase was designed and employed as the support for loading AuPd bimetal with different proportions to synthesize AuPd/HB-ZrO_(2) catalysts.The effects of surface chemistry,oxygen defects,bimetal interaction and metal-support interaction of AuPd/HB-ZrO_(2) on catalytic performance for the selective oxidation of 5-hydroxymethylfurfural(HMF)to 2,5-furandicarboxylic acid(FDCA)were systematically investigated.The Au 2 Pd1/HB-ZrO_(2) catalyst afforded a satisfactory FDCA yield of 99.9%from HMF oxidation using O_(2) as the oxidant in water,accompanied with an excellent FDCA productivity at 97.6 mmol g^(−1) h^(−1).This work offers fresh insights into rationally designing efficient catalysts with oxygen-rich defects for the catalytic upgrading of biomass platform chemicals.展开更多
基金the financial support from the National Natural Science Foundation of China(No.51801078).
文摘To modify the thermodynamics and kinetic performance of magnesium hydride(MgH_(2))for solid-state hydrogen storage,Ni_(3)V_(2)O_(8)-rGO(rGO represents reduced graphene oxide)and Ni_(3)V_(2)O_(8)nanocomposites were prepared by hydrothermal and subsequent heat treatment.The beginning hydrogen desorption temperature of 7 wt.%Ni_(3)V_(2)O_(8)-rGO modified MgH_(2)was reduced to 208℃,while the additive-free MgH_(2)and 7 wt.%Ni_(3)V_(2)O_(8)doped MgH_(2)appeared to discharge hydrogen at 340 and 226℃,respectively.A charging capacity of about 4.7 wt.%H_(2)for MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO was achieved at 125℃ in 10 min,while the dehydrogenated MgH_(2)took 60 min to absorb only 4.6 wt.%H_(2)at 215℃.The microstructure analysis confirmed that the in-situ generated Mg_(2)Ni/Mg_(2)N_(i)H_(4) and metallic V contributed significantly to the enhanced performance of MgH_(2).In addition,the presence of rGO in the MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO composite reduced particle aggregation tendency of Mg/MgH_(2),leading to improving the cyclic stability of MgH_(2)during 20 cycles.
基金financial support provided by the National Key R&D Program of China(2017YFC0210901,2017YFC0210906)National Natural Science Foundation of China(51573122,21722607,21776190)+2 种基金Natural Science Foundation of the Jiangsu Higher Education Institutions of China(17KJA430014,17KJA150009)the Science and Technology Program for Social Development of Jiangsu(BE2015637)the project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Improving catalytic performance is a yet still challenge in thermal catalytic oxidation.Herein,uniform mesoporous MnO_(2) nanospheresupported bimetallic Pt–Pd nanoparticles were successfully fabricated via a SiO_(2) template strategy for the total catalytic degradation of volatile organic compounds at low temperature.The introduction of mesopores into the MnO_(2) support induces a large specific surface area and pore size,thus providing numerous accessible active sites and enhanced diffusion properties.Moreover,the addition of a secondary noble metal can adjust the O_(ads)/O_(latt) molar ratios,resulting in high catalytic activity.Among them,the catalyst having a Pt/Pd molar ratio of 7:3 exhibits optimized catalytic activity at a weight hourly space velocity of 36,000 mL g^(-1) h^(-1),reaching 100%toluene oxidation at 175℃ with a lower activation energy(57.0 kJ mol^(-1))than the corresponding monometallic Pt or non-Pt-based catalysts(93.8 kJ mol^(-1) and 214.2 kJ mol^(-1)).Our findings demonstrate that the uniform mesoporous MnO_(2) nanosphere-supported bimetallic Pt–Pd nanoparticles catalyst is an effective candidate for application in elimination of toluene.
基金Supported by the National Natural Science Foundation of China(21476211)the Zhejiang Provincial Natural Science Foundation of China(LY16B060004 and LY18B060016)
文摘In the present work, a series of Pt-based catalysts, alloyed with a second metal, i.e., Re, Sn, Er, La, and Y, and supported on activated carbon, ordered mesoporous carbon, N-doped mesoporous carbon or reduced graphene oxide(rGO), have been developed for selective hydrogenation of cinnamaldehyde to cinnamylalcohol. Re and rGO were proved to be the most favorable metal dopant and catalyst support, respectively. Pt_(50) Re_(50)/rGO showed the highest cinnamylalcohol selectivity of 89% with 94% conversion of cinnamaldehyde at the reaction conditions of 120 °C, 2.0 MPaH_2 and 4 h.
基金supported by the National Key R&D Program of China(No.2020YFB2008604,2021YFB3202500)the National Natural Science Foundation of China(No.61874034)the International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300)。
文摘Highly sensitive gas sensors with remarkably low detection limits are attractive for diverse practical application fields including real-time environmental monitoring,exhaled breath diagnosis,and food freshness analysis.Among various chemiresistive sensing materials,noble metal-decorated semiconducting metal oxides(SMOs)have currently aroused extensive attention by virtue of the unique electronic and catalytic properties of noble metals.This review highlights the research progress on the designs and applications of different noble metal-decorated SMOs with diverse nanostructures(e.g.,nanoparticles,nanowires,nanorods,nanosheets,nanoflowers,and microspheres)for high-performance gas sensors with higher response,faster response/recovery speed,lower operating temperature,and ultra-low detection limits.The key topics include Pt,Pd,Au,other noble metals(e.g.,Ag,Ru,and Rh.),and bimetals-decorated SMOs containing ZnO,SnO_(2),WO_(3),other SMOs(e.g.,In_(2)O_(3),Fe_(2)O_(3),and CuO),and heterostructured SMOs.In addition to conventional devices,the innovative applications like photo-assisted room temperature gas sensors and mechanically flexible smart wearable devices are also discussed.Moreover,the relevant mechanisms for the sensing performance improvement caused by noble metal decoration,including the electronic sensitization effect and the chemical sensitization effect,have also been summarized in detail.Finally,major challenges and future perspectives towards noble metal-decorated SMOs-based chemiresistive gas sensors are proposed.
基金Project(51004053)supported by National Natural Science Foundation of ChinaProject(2009J01033)supported by Natural Science Foundation of Fujian Province,China+2 种基金Project(3502Z20116008)supported by the Science and Technology Research Project of Xiamen City,ChinaProject(JA11146)supported by Program for Fostering Distinguished Young Scholars in University of Fujian Province,ChinaProject(2011B003)supported by the Foundation for Young Professors of Jimei University,China
文摘In the present work, a novel heterogeneous photo-Fenton catalyst was prepared by iron and cerium pillared bentonite. The catalyst Fe-Ce/bentonite was characterized by X-ray diffraction （XRD）, X-ray fluorescence （XRF）, Brunauer-Emmett-Teller （BET） and scanning electron microscopy （SEM） methods. It is found that Fe and Ce intercalate into the silicate layers of bentonite successfully. Tetracycline was removed by heterogeneous photo-Fenton reaction using the catalyst in this work. The effects of different reaction systems, hydrogen peroxide concentration, initial pH, catalyst dosage, UV power and introduction of different anions on degradation were investigated in details. The stability of catalyst was investigated through recycling experiment. The results show that removal rate of tetracycline is 98.13% under the conditions of 15 mmol/L H202, 0.50 g/L catalyst dosage, initial pH 3.0, 11 W UV lamp power and 60 min reaction time. However, the removal rate decreases after adding some anions. The hydroxyl radical plays an important role in heterogeneous photo-assisted Fenton degradation of tetracycline. The catalyst is very stable and can be recycled many times.
基金the Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)and Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)Programa de Pós-Graduacao em Agroquímica/UFLA(PPGAQ)+1 种基金Programa de Pós-Graduacao Multicêntrico em Química/UFLA(PPGMQ-MG)Centro de Prospeccao Química(CAPQ-UFLA)。
文摘This study highlights introducing the rare earth metal cerium(Ce(Ⅳ))into the structure of magnetite(Fe_(3)O_(4))to achieve enhanced adsorptive properties for the removal of chromium(Cr(VI))from an aqueous medium.Different ratios of Ce(Ⅳ)were introduced into the iron oxide matrix,termed FeCe-5,FeCe-10,and FeCe-20.Their numerical values correspond to the nominal content of the dopant element added to the synthesis medium.The solid materials were characterized for morphology and chemical structure,and N_(2)physical adsorption/desorption measurements were performed.The solid materials doped with Ce(IV)have a high surface area compared to Fe_(3)O_(4),and the solid material with the highest content of the dopant ion(Ce(IV))has a 4-fold greater surface area.This increase in the dopant content in the iron oxide structure leads to a total chromium removal of 93.3%.Isotherms studies on the solid materials show that chromium adsorption follows the Langmuir model.The adsorption capacity to Fe_(3)O_(4)is 12.59 mg/g and FeCe-10 is 22.49 mg/g at 35℃.By fitting the kinetic and isothermal models,it is found that for the Fe_(3)O_(4)and FeCe-10 materials Cr(VI)removal occurs in very different ways,attributed to the different surface areas and compositions of the oxide,with the formation of the goethite(α-FeOOH)phase.The FeCe-10reuse process was performed and the removal capacity the Cr(VI)is reduced after the first cycle.This result is attributed to a strong and irreversible adsorption of Cr(VI)on the FeCe-10.
文摘The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared between the Al22 Si and ZL102 bimetal.The average bonding strength of bimetal with intermittent oxide film interface was about 89.3MPa,which is higher than that of the bimetal fabricated by zinc coating method（about 76.3MPa）.During the process of extrusion,the oxidation film was extruded to crush and the metal was extruded through the micro-cracks of the oxidation film,then the two surfaces were joined together.Altogether,the results showed that extrusion at near-eutectic temperature is favorable for achieving a high-quality metallurgical bonded interface.
基金the National Natural Science Foundation of China(Nos.21677055 and 21407052)National Key Research and Development Program of China(No.2019YFC1805204)+1 种基金Project of Three Gorges Corporation(No.JDZC-FW-20-001)the Fundamental Research Funds for the Central Universities,HUST(No.2017KFXKJC004)。
文摘This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac(DCF),as compared to much slow removal of DCF by Cu(Ⅱ) or zero valent iron nanoparticles(nZVI),respectively.Further observations on the evolution of O_(2) activation process by nano Fe/Cu bimetals was conducted stretching to the preparation phase(started by nZVI/Cu2+).Interesting breakpoints we re observed with obvious sudden increase in the DCF degradation efficiency and decrease in solution pH,as the original nZVI just consumed up to Fe(Ⅱ) and Cu(II) appeared again.It suggested that the four-electrons reaction of O_(2) and Cu-deposited nZVI would occur to generate water prior to the breakpoints,while Cu(0) and Fe(Ⅱ) would play most important role in activation of O_(2) afterwards.Through the electron spin resonance(ESR) analysis and quenching experiments.·OH was identified as the responsible reactive species.Further time-dependent quantifications in the cases of Cu(0)/Fe(Ⅱ) systems we re carried out.It was found that the ’OH accumulation was positively and linearly correlated with nCu dose,Fe(Ⅱ) consumption,and Fe(II) dose,respectively.Since either Cu(O) or Fe(Ⅱ)would be inefficient in activating oxygen to produce ·OH,a stage-evolution mechanism of O_(2) activated by nano Fe/Cu bimetals was proposed involving:(a) Rapid consumption of Fe(0) and release of Fe(Ⅱ) based on the Cu-Fe galvanic corrosion,(b) adsorption and transformation of O_(2) to O_(2)2 at the nCu surface,and(c) Fe(Ⅱ)-catalyzed activation of the adsorbed O_(2)2 to ·OH.
基金Project supported by National Natural Science Foundation of China(22076180)Youth Innovation Promotion Association of CAS(2019376)Chongqing Bayu Scholar Program(Young Scholar,YS2020048)。
文摘Creating a new low-temperature catalyst in decreasing the emission of volatile organic compounds(VOCs)has great significance under different industrial production situations.In particular,the Zr-UiO-66 is optimized by different amounts of cerium,which not only enhances the physicochemical stability but also increases the number of active sites of Ce_(x)Zr_(y)UiO-66.Furthermore,the catalysts with Co_(3)O_(4)nanoparticles supported on Ce_(x)Zr_(y)UiO-66 were successfully prepared via impregnation method.In the process of toluene degradation,the Co/Ce_(1)Zr_(2)-Ui0-66 attains a 90%conversion rate at 210℃with a space velocity of 60000 mL/(g·h)and toluene concentration at 1000×10^(-6).Meanwhile,the carbon dioxide selectivity reaches 100%at 218℃.The Co/Ce_(1)Zr_(2)-UiO-66 shows great water resistance(3 vol%H_(2)O).Multiple characterization methods were used to figure out the physicochemical properties of the catalysts.It is found that the addition of an appropriate amount of cerium can enhance stability of UiO-66 and surface lattice oxygen proportion.Additionally,the stronger electron transfer between Ce^(4+)and Co^(2+)enables the Co/Ce_(1)Zr_(2)-UiO-66 to possess more active surface oxygen species and Co_(3)+cationic species in all samples.
基金Supported by the Key Program of the National Natural Science Foundation of China(21036007)the National High-Tech Project of China(2012AA062903)
文摘Novel Mg O–SBA-15 supported catalysts were prepared for oxidative esterification of methacrolein(MAL) with methanol to methyl methacrylate(MMA). The Mg O–SBA-15 supports were synthesized with different magnesia loadings from different magnesium precursors and hydrochloric acid molar concentrations. The Mg O–SBA-15 supports and Pd–Pb/Mg O–SBA-15 catalysts were characterized by several analysis methods. The results revealed that the addition of Mg O improved the ordered structure of SBA-15 supports and provided surface alkalinity of SBA-15 supports. The average size of the Pd3 Pb particles on magnesia-modified Pd–Pb/Mg O–SBA-15 catalysts was smaller than that on the pure silica-based Pd–Pb/SBA-15 catalysts. The experiments on catalyst performance showed that the magnesia-modified Pd–Pb/Mg O–SBA-15 catalysts had higher activity than pure silica-based Pd–Pb/SBA-15 catalysts, showing the strong dependence of catalytic activity on the average size of active particles. The difference of activity between Pd–Pb/SBA-15 catalysts and Pd–Pb/Mg O–SBA-15 catalysts was due to the discrepant structural properties and surface alkalinity provided by Mg O, which led to the different Pd3 Pb particle sizes and then resulted in the different number of active sites. Besides magnesia loadings, other factors, such as hydrochloric acid molar concentration and magnesium precursors, had considerable influences on the catalytic activity.
基金the financial supports from the National Natural Science Foundation of China(21902062 and 21705056)the Natural Science Foundation of Shandong Province(ZR2019YQ10 and ZR2018PB009)+1 种基金the Young Taishan Scholars Program(tsqn201812080)the Open Funds of the State Key Laboratory of Electroanalytical Chemistry(SKLEAC201901)。
文摘Developing electrocatalysts with high performance and low cost for the oxygen evolution reaction(OER)is of great importance for fabricating renewable energy storage and conversion devices.Here,a series of boron-doped graphene(BG)-supported bimetallic oxides of Co and Ni were obtained and served as OER electrocatalysts.Surprisingly,the annealed Co-Ni-Ox/BG with a Co/Ni ratio of 1:1 exhibits high performance toward oxygen evolution in alkaline electrolyte.The overpotential is only 310 mV at the current density of 10 mA cm-2,superior to many mono-metallic oxides reported before,and even comparable to the commercial RuO2.The regulation of charge distribution in bimetallic oxides and the strong synergistic coupling effects together contribute to the superior electrocatalytic performance of the Co-Ni-Ox/BG toward OER.This study also offers several effective ways to design high-performance OER electrocatalysts for water splitting.
基金supported by National Research Foundation(NRF)grants funded by the Ministry of Science and ICT,Republic of Korea(NRF-2022R1A2C1004392)and SI thanks ARCCA,Cardiff,for computing time.
文摘Precisely tuning bicomponent intimacy during reactions by traditional methods remains a formidable challenge in the fabrication of highly active and stable catalysts because of the difficulty in constructing well-defined catalytic systems and the occurrence of agglomeration during assembly.To overcome these limitations,a PtRuPNiO@TiO_(x)catalyst on a Ti plate was prepared by ultrasound-assisted low-voltage plasma electrolysis.This method involves the oxidation of pure Ti metal and co-reduction of strong metals at 3000◦C,followed by sonochemical ultrasonication under ambient conditions in an aqueous solution.The intimacy of the bimetals in PtRuPNiO@TiOx is tuned,and the metal nanoparticles are uniformly distributed on the porous titania coating via strong metal-support interactions by leveraging the instantaneous high-energy input from the plasma discharge and ultrasonic irradiation.The intimacy of PtRuPNiO@TiO_(x)increases the electron density on the Pt surface.Consequently,the paired sites exhibit a high hydrogen evolution reaction activity(an overpotential of 220 mV at a current density of 10 mA cm^(−2)and Tafel slope of 186 mV dec^(−1)),excellent activity in the hydrogenation of 4-nitrophenol with a robust stability for up to 20 cycles,and the ability to contrast stated catalysts without ultrasonication and plasma electrolysis.This study facilitates industrially important reactions through synergistic chemical interactions.
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20200917)the China Postdoctoral Science Foundation(No.2021M701474)+1 种基金Youth Talent Cultivation Plan of Jiangsu UniversityCollaborative Innovation Center for Water Treatment Technology and Materials.
文摘The unique properties of metal oxide surfaces,crystal surfaces and defects play vital roles in biomass upgrading reactions.In this work,hierarchical porous bowl-shaped ZrO_(2)(HB-ZrO_(2))with mixed crystal phase was designed and employed as the support for loading AuPd bimetal with different proportions to synthesize AuPd/HB-ZrO_(2) catalysts.The effects of surface chemistry,oxygen defects,bimetal interaction and metal-support interaction of AuPd/HB-ZrO_(2) on catalytic performance for the selective oxidation of 5-hydroxymethylfurfural(HMF)to 2,5-furandicarboxylic acid(FDCA)were systematically investigated.The Au 2 Pd1/HB-ZrO_(2) catalyst afforded a satisfactory FDCA yield of 99.9%from HMF oxidation using O_(2) as the oxidant in water,accompanied with an excellent FDCA productivity at 97.6 mmol g^(−1) h^(−1).This work offers fresh insights into rationally designing efficient catalysts with oxygen-rich defects for the catalytic upgrading of biomass platform chemicals.
