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
X-ray diffraction and selective chemical dissolution methods were used to investigate the composition of Mn oxide minerals in Fe-Mn nodules of several main types of soils in China. The changes of relative intensity of...X-ray diffraction and selective chemical dissolution methods were used to investigate the composition of Mn oxide minerals in Fe-Mn nodules of several main types of soils in China. The changes of relative intensity of X-ray diffraction patterns were studied both before and after chemically selective dissolution. It was found that lithiophorite was a common Mn oxide in all examined Fe-Mn nodules. Todorokite, however, was a predominant Mn oxide in Fe-Mn nodules in caf-aquic Vertisols of Linyi, Shandong Province. The Fe-Mn nodules of arp-udic Luvisols in Wuhan and Zaoyang, Hubei Province, contained birnessite and vernadite. Hollandite was found in Fe-Mn nodules of alt-udic Ferrisols of Yizhang, Hunan Province; arp-udic Luvisols of Zaoyang, Hubei Province; and cal-aquic Vertisols of Linyi, Shandong Province. The Fe-Mn nodules in alt-udic Ferrisols of Guiyang, Hunan Province, had a few coronadites. Mineralogy of Mn oxide minerals in soil Fe-Mn nodules was related to soil environment, soil types and quantities of relevant cations.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
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
FePt bimetallic nanoparticles were formed on reduced graphene oxide（rGO） with the help of double-stranded DNA（dsDNA） via a simple and universal route to obtain a FePt/DNA-rGO composite. The FePt nanoparticles with...FePt bimetallic nanoparticles were formed on reduced graphene oxide（rGO） with the help of double-stranded DNA（dsDNA） via a simple and universal route to obtain a FePt/DNA-rGO composite. The FePt nanoparticles with an average size of about 5 nm were well dispersed on rGO. FePt/DNA-rGO modified glassy carbon electrode（GCE） exhibited excellent electrocatalytic activity for the oxidation of dopamine（DA） with a detec- tion limit of 100 nmol/L（S/N = 3）. In addition, the FePt/DNA-rGO based electrochemical sensor showed an excellent selectivity for DA in the presence of ascorbic acid（AA）, uric acid（UA） and other interference reagents. The as-prepared electrochemical biosensor shows great promise in the application of clinical diagnostics.展开更多
Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments.A series of FeMn binary oxide with different Fe：Mn molar ratios was synthesized by a simultaneous...Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments.A series of FeMn binary oxide with different Fe：Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal.Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide,and that the oxide with a Fe：Mn molar ratio of 5：1 was the best in removal than other molar ratios.The tetracycline removal was highly pH dependent.The removal of tetracycline decreased with the increase of initial concentration,but the absolute removal quantity was more at high concentration.The presence of cations and anions such as Ca2＋,Mg2＋,CO32-and SO42-had no significant effect on the tetracycline removal in our experimental conditions,while SiO32-and PO43-had hindered the adsorption of tetracycline.The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface.This primary study suggests that Fe-Mn binary oxide with a proper Fe：Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions.展开更多
Cadmium (Cd) and arsenic (As) are two of the most toxic elements.However,the chemical behaviors of these two elements are different,making it challenging to utilize a single adsorbent with high adsorption capacity for...Cadmium (Cd) and arsenic (As) are two of the most toxic elements.However,the chemical behaviors of these two elements are different,making it challenging to utilize a single adsorbent with high adsorption capacity for both Cd(Ⅱ) and As(Ⅴ) removal.To solve this problem,we synthesized HA/Fe-Mn oxides-loaded biochar (HFMB),a novel ternary material,to perform this task,wherein scanning electron microscopy (SEM) combined with EDS (SEM-EDS) was used to characterize its morphological and physicochemical properties.The maximum adsorption capacity of HFMB was 67.11 mg/g for Cd(Ⅱ) and 35.59 mg/g for As(Ⅴ),which is much higher compared to pristine biochar (11.06 mg/g,0 mg/g for Cd(Ⅱ) and As(Ⅴ),respectively).The adsorption characteristics were investigated by adsorption kinetics and the effects of the ionic strength and pH of solutions.X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) revealed that chelation and deposition were the adsorption mechanisms that bound Cd(Ⅱ) to HFMB,while ligand exchange was the adsorption mechanism that bound As(Ⅴ).展开更多
The adsorption potential of FMBO, FeOOH, MnO2 for the removal of Cd^2＋, Cu^2＋ and Pb^2＋ in aqueous systems was investigated in this study. Comparing to FMBO and FeOOH, MnO2 offered a much higher removal capacity to...The adsorption potential of FMBO, FeOOH, MnO2 for the removal of Cd^2＋, Cu^2＋ and Pb^2＋ in aqueous systems was investigated in this study. Comparing to FMBO and FeOOH, MnO2 offered a much higher removal capacity towards the three metal ions. The maximal adsorption capacity of MnO2 for Cd^2＋, Cu^2＋ and Pb^2＋ were 1.23, 2.25 and 2.60 mmol· g^-1, respectively. And that for FMBO were 0.37, 1.13, and 1.18mmol·g^-1 and for FeOOH were 0.11, 0.86 and 0.48 mmol·g^-1, respectively. The adsorption behaviors of the three metal ions on the three adsorbents were all significantly affected by pH values and heavy metal removal efficiency increased with pH increased. The Langmuir and Freundlieh adsorption models were used to describe the adsorption equilibrium of the three metal ions onto the three adsorbents. Results showed that the adsorption equilibrium data fitted well to Langmuir isotherm and this indicated that adsorption of metal ions occurred on the three metal oxides adsorbents limited to the formation of a monolayer. More negative charged of MnOa surface than that of FMBO and FeOOH could be ascribed by lower pHiep of MnO2 than that of FMBO and FeOOH and this could contribute to more binding sites on MnO2 surface than that of FMBO and FeOOH. The higher metal ions uptake by MnO2 than FMBO and FeOOH could be well explained by the surface charge mechanism.展开更多
The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. ...The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. The molar ratio of Fe and Mn in the synthetic Fe-Mn binary oxides was 4 ： 3. The FM-1 and FM-2（prepared at different activation temperatures） having high specific surface areas（358.87 and 128.58 m^2/g, respectively） were amorphous and of nano particle types. The amount of arsenic adsorbed on FM-1 was higher than that adsorbed on FM-2 particles. After adsorption by FM-1, residual arsenic concentration decreased to less than 10 μg/L. The adsorption kinetics data were analyzed using different kinetic models including pseudo first-order model, pseudo second-order model, Elovich model and intraparticle diffusion model. Pseudo second-order kinetic model was the most appropriate model to describe the adsorption kinetics. The adsorption percentage of As（Ⅲ） increased in the p H range of 2–3 while it decreased with the increase of pH（ 3〈pH〈10）. The effects of coexisting anions on As（Ⅲ） removal using FM-1 and FM-2 were also studied and the order of the effects is as follows： NO_3^-, Cl-, F-〈SO_4^（2-）, HCO_3-〈H_2PO_4^-, indicating that H_2PO_4^- is the major competitor with As（Ⅲ） for adsorptive sites on the surface of the adsorbents. The higher adsorption capacity of FM-1 makes it potentially attractive adsorbent for the removal of As（Ⅲ） from groundwater.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Project(No.49771049)supported by the National Natural Science Foundation of China
文摘X-ray diffraction and selective chemical dissolution methods were used to investigate the composition of Mn oxide minerals in Fe-Mn nodules of several main types of soils in China. The changes of relative intensity of X-ray diffraction patterns were studied both before and after chemically selective dissolution. It was found that lithiophorite was a common Mn oxide in all examined Fe-Mn nodules. Todorokite, however, was a predominant Mn oxide in Fe-Mn nodules in caf-aquic Vertisols of Linyi, Shandong Province. The Fe-Mn nodules of arp-udic Luvisols in Wuhan and Zaoyang, Hubei Province, contained birnessite and vernadite. Hollandite was found in Fe-Mn nodules of alt-udic Ferrisols of Yizhang, Hunan Province; arp-udic Luvisols of Zaoyang, Hubei Province; and cal-aquic Vertisols of Linyi, Shandong Province. The Fe-Mn nodules in alt-udic Ferrisols of Guiyang, Hunan Province, had a few coronadites. Mineralogy of Mn oxide minerals in soil Fe-Mn nodules was related to soil environment, soil types and quantities of relevant cations.
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the National Natural Science Foundation of ChinafNos.21235004, 21327806.
文摘FePt bimetallic nanoparticles were formed on reduced graphene oxide（rGO） with the help of double-stranded DNA（dsDNA） via a simple and universal route to obtain a FePt/DNA-rGO composite. The FePt nanoparticles with an average size of about 5 nm were well dispersed on rGO. FePt/DNA-rGO modified glassy carbon electrode（GCE） exhibited excellent electrocatalytic activity for the oxidation of dopamine（DA） with a detec- tion limit of 100 nmol/L（S/N = 3）. In addition, the FePt/DNA-rGO based electrochemical sensor showed an excellent selectivity for DA in the presence of ascorbic acid（AA）, uric acid（UA） and other interference reagents. The as-prepared electrochemical biosensor shows great promise in the application of clinical diagnostics.
基金supported by the Fund for the Creative Research Groups of China (No. 50921064)the Special Co-construction Project of Beijing Municipal Commission of Education
文摘Significant concerns have been raised over the presence of antibiotics including tetracyclines in aquatic environments.A series of FeMn binary oxide with different Fe：Mn molar ratios was synthesized by a simultaneous oxidation and coprecipitation process for TC removal.Results showed that Fe-Mn binary oxide had higher removal efficiency than that of hydrous iron oxide and hydrous manganese oxide,and that the oxide with a Fe：Mn molar ratio of 5：1 was the best in removal than other molar ratios.The tetracycline removal was highly pH dependent.The removal of tetracycline decreased with the increase of initial concentration,but the absolute removal quantity was more at high concentration.The presence of cations and anions such as Ca2＋,Mg2＋,CO32-and SO42-had no significant effect on the tetracycline removal in our experimental conditions,while SiO32-and PO43-had hindered the adsorption of tetracycline.The mechanism investigation found that tetracycline removal was mainly achieved by the replacement of surface hydroxyl groups by the tetracycline species and formation of surface complexes at the water/oxide interface.This primary study suggests that Fe-Mn binary oxide with a proper Fe：Mn molar ratio will be a very promising material for the removal of tetracycline from aqueous solutions.
基金supported by the National Key Research and Development Project of China(No.2016YFD0800706)the Science and Technology Project of Fujian Province of China(No.2018Y0080)the Science and Technology Project of Xiamen(No.3502Z20172026)
文摘Cadmium (Cd) and arsenic (As) are two of the most toxic elements.However,the chemical behaviors of these two elements are different,making it challenging to utilize a single adsorbent with high adsorption capacity for both Cd(Ⅱ) and As(Ⅴ) removal.To solve this problem,we synthesized HA/Fe-Mn oxides-loaded biochar (HFMB),a novel ternary material,to perform this task,wherein scanning electron microscopy (SEM) combined with EDS (SEM-EDS) was used to characterize its morphological and physicochemical properties.The maximum adsorption capacity of HFMB was 67.11 mg/g for Cd(Ⅱ) and 35.59 mg/g for As(Ⅴ),which is much higher compared to pristine biochar (11.06 mg/g,0 mg/g for Cd(Ⅱ) and As(Ⅴ),respectively).The adsorption characteristics were investigated by adsorption kinetics and the effects of the ionic strength and pH of solutions.X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) revealed that chelation and deposition were the adsorption mechanisms that bound Cd(Ⅱ) to HFMB,while ligand exchange was the adsorption mechanism that bound As(Ⅴ).
文摘The adsorption potential of FMBO, FeOOH, MnO2 for the removal of Cd^2＋, Cu^2＋ and Pb^2＋ in aqueous systems was investigated in this study. Comparing to FMBO and FeOOH, MnO2 offered a much higher removal capacity towards the three metal ions. The maximal adsorption capacity of MnO2 for Cd^2＋, Cu^2＋ and Pb^2＋ were 1.23, 2.25 and 2.60 mmol· g^-1, respectively. And that for FMBO were 0.37, 1.13, and 1.18mmol·g^-1 and for FeOOH were 0.11, 0.86 and 0.48 mmol·g^-1, respectively. The adsorption behaviors of the three metal ions on the three adsorbents were all significantly affected by pH values and heavy metal removal efficiency increased with pH increased. The Langmuir and Freundlieh adsorption models were used to describe the adsorption equilibrium of the three metal ions onto the three adsorbents. Results showed that the adsorption equilibrium data fitted well to Langmuir isotherm and this indicated that adsorption of metal ions occurred on the three metal oxides adsorbents limited to the formation of a monolayer. More negative charged of MnOa surface than that of FMBO and FeOOH could be ascribed by lower pHiep of MnO2 than that of FMBO and FeOOH and this could contribute to more binding sites on MnO2 surface than that of FMBO and FeOOH. The higher metal ions uptake by MnO2 than FMBO and FeOOH could be well explained by the surface charge mechanism.
基金supported by the National Natural Science Foundation of China(No.41120124003)the Ministry of Science and Technology of China(No.2012AA062602)the 111 project and Priority Development Projects of SRFDP of the Ministry of Education of China
文摘The adsorptive removal of arsenic by synthetically-prepared nano Fe-Mn binary oxides（FM） was investigated. A novel method using potassium permanganate and ferric chloride as raw materials was used to synthesise FM. The molar ratio of Fe and Mn in the synthetic Fe-Mn binary oxides was 4 ： 3. The FM-1 and FM-2（prepared at different activation temperatures） having high specific surface areas（358.87 and 128.58 m^2/g, respectively） were amorphous and of nano particle types. The amount of arsenic adsorbed on FM-1 was higher than that adsorbed on FM-2 particles. After adsorption by FM-1, residual arsenic concentration decreased to less than 10 μg/L. The adsorption kinetics data were analyzed using different kinetic models including pseudo first-order model, pseudo second-order model, Elovich model and intraparticle diffusion model. Pseudo second-order kinetic model was the most appropriate model to describe the adsorption kinetics. The adsorption percentage of As（Ⅲ） increased in the p H range of 2–3 while it decreased with the increase of pH（ 3〈pH〈10）. The effects of coexisting anions on As（Ⅲ） removal using FM-1 and FM-2 were also studied and the order of the effects is as follows： NO_3^-, Cl-, F-〈SO_4^（2-）, HCO_3-〈H_2PO_4^-, indicating that H_2PO_4^- is the major competitor with As（Ⅲ） for adsorptive sites on the surface of the adsorbents. The higher adsorption capacity of FM-1 makes it potentially attractive adsorbent for the removal of As（Ⅲ） from groundwater.
