The ordered bimodal mesoporous silica MCM-48 spheres were facile synthesized by mild- temperature post-synthesis H2O2 hydrothermal treatment of as-synthesized MCM-48. The results showed that H2O2 is indispensable for ...The ordered bimodal mesoporous silica MCM-48 spheres were facile synthesized by mild- temperature post-synthesis H2O2 hydrothermal treatment of as-synthesized MCM-48. The results showed that H2O2 is indispensable for simultaneously removing organic templates and forming ordered bimodal mesoporous silica MCM-48 spheres. The bimodal mesoporous MCM-48 was characterized by X-ray diffraction, transmission electron micrographs, FT-IR, and N2 adsorption-desorption, and a possible mechanism was proposed for the formation of bimodal mesoporous MCM-48.展开更多
Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-T...Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-TiO2 were used as catalytic supports to load Pd nanoparticles for H2 O2 direct synthesis from H2 and O2. The as-prepared samples were systematically studied by transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), air isothermal microcalorimeter, temperature-programmed reduction of H2(H2-TPR), and so on. The catalytic results showed that H2 O2 productivity and H2O2 selectivity of Pd/C-TiO2 firstly rose with increasing carbon content and then declined. Pd/C-TiO2 catalyst with 1.89 wt% of carbon content showed the best catalytic performance that had 61.2% of selectivity and 2192 mmol H2O2/g Pd/h of productivity, which were significantly better than those of pristine Pd/TiO2(45.2% and 1827 mmol H2O2/g Pd/h). Various characterization results displayed that the carbon species were heterogeneously dispersed on TiO2 surface. Moreover, no obvious geometric transformation in supports and Pd nanoparticles were observed among different catalysts. The superficial hydrophobicity of Pd/C-TiO2 was gradually promoted with increasing carbon content, which led to the corresponding decrease in adsorption energy of H2O2 with catalysts. According to structure-performance relationship analyses, the heterogeneous interfacial engineering of carbon could maintain the interaction of Pd nanoparticles with TiO2 and simultaneously accelerate the H2O2 desorption. Both factors further determined the excellent H2O2 direct synthesis performance of Pd/C-TiO2.展开更多
The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results sh...The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.展开更多
Objective To identify the osteogenesis genes whose expression is altered in hypertrophic chondrocytes treated with H2 O2.Methods Murine chondrogenitor cells(ATDC5) were differentiated into hypertrophic chondrocytes by...Objective To identify the osteogenesis genes whose expression is altered in hypertrophic chondrocytes treated with H2 O2.Methods Murine chondrogenitor cells(ATDC5) were differentiated into hypertrophic chondrocytes by InsulinTransferrin-Selenium(ITS) treatment, and then treated with H2 O2. Suitable conditions(concentration, time) were determined by using the MTT assay. After total RNA isolation and cD NA synthesis, the levels of 84 genes were determined using the PCR array, whereas quantitative RT-PCR was carried out to validate the PCR array data. Results We identified 9 up-regulated genes and 12 down-regulated genes, encoding proteins with various functions, such as collagen proteins, transcription factors, proteins involved in skeletal development and bone mineral metabolism, as well as cell adhesion molecules. Quantitative RT-PCR confirmed the altered expression of 5 down-regulated genes(Smad2, Smad4, transforming growth factor β receptor 1, transforming growth factor β receptor 3, and matrix metalloproteinase 10). Conclusions H2 O2 significantly changed the expression of several genes involved in a variety of biological functions. Because of the link between oxidative damage and Kashin-Beck disease, these genes may also be involved in the deep-zone necrosis of the cartilage observed in Kashin-Beck disease.展开更多
Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N...Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.展开更多
Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science.Especially,it is attractive to exploit noble-metal-free nanomaterials with large sur...Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science.Especially,it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors.Herein,we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes(Co3O4/NCNTs)hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air.The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions.As sensor electrode,the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40μA(mmol/L)^-1 cm^-2,a linear range of 5.00μmol/L-11.00 mmol/L,and a detection limitation of 1μmol/L in H2O2 detection,and a good glucose detection performance with 5μmol/L.These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.展开更多
Development of sensitive biosensors for biocatalytic transformations monitoring is in high demand but remains a great challenge. It is ascribed to the current strategies that focused on the single metabolite detection...Development of sensitive biosensors for biocatalytic transformations monitoring is in high demand but remains a great challenge. It is ascribed to the current strategies that focused on the single metabolite detection, which may bring about the relatively low sensitivity and false diagnosis result. Herein, we report the design and fabrication of novel carbon dots(CDs) with strong orange light emission, pH and H2O2 dual-responsive characteristics. The fluorescence quenching of CDs by H+and H2O2 enables the highly sensitive detection of H+/H2O2-generating biocatalytic transformations. This is exemplified by the glucose oxidase-mediated catalytic oxidation reaction on glucose, in which H+and H2O2 would be formed. As compared to the case in which glucose is present, significant fluorescence reduction is detected, and the fluorescence intensity is negatively proportional to glucose concentration. Thus, highly sensitive detection of glucose was readily achieved with a detection limit down to 10.18 nmol/L. The prepared CDs not only realize the highly sensitive detection of glucose, but also allows the probing other substances by changing the enzymes, thus providing a versatile platform, and demonstrating good potential to be used for biocatalytic transformations effective monitoring.展开更多
Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis...Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis from H2 and O2. Based on mechanistic information available mostly for liquid phase catalytic processes, feasible reaction mechanisms for such coupled reactions are proposed based on which desirable catalyst properties are identified. It is found that the surface-adsorbed oxygen bond is an important parameter for identifying desirable catalysts. Thermodynamics can be used to identify the types of organic oxidation reactions that can couple with water oxidation such that H2O2 formation becomes thermodynamically favorable. Reactions such as epoxidation of alkenes and selective oxidation of alkanes to alcohols cannot provide sufficient thermodynamic driving force, whereas oxidation of alcohols to aldehydes and to acids can. Finally, further research is suggested to identify catalytic properties important for H2O2 decomposition and for coupling selective oxidation of organic compounds to oxidation of H2O in order to facilitate development of H2O2 production coupled with selective organic oxidation.展开更多
A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observe...A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.展开更多
This study used a bioelectrochemical system (BES) to produce H2O2.Seven cycles after the addition of microorganisms,the BES started successfully and entered a stable operation period.During stable operation,the voltag...This study used a bioelectrochemical system (BES) to produce H2O2.Seven cycles after the addition of microorganisms,the BES started successfully and entered a stable operation period.During stable operation,the voltage was 581 mV,the COD removal efficiency at the anode was 85.39%,and the H 2O 2 mass concentration at the cathode was 0.5%.After the addition of 10% of graphite particles in the reaction chamber,the H2O2 production increased by 13%.After loading Pt-containing carbon black catalyst on the cathode,the H2O2 production increased by 34%.The mass concentration of H2O2 was 0.67% under the optimum process conditions of a cathode loaded with Pt-containing carbon black catalyst,pH=7,and dissolved oxygen of 8 mg/L.展开更多
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20872135） and the China National Tobacco Corporation （No.110200701007）.
文摘The ordered bimodal mesoporous silica MCM-48 spheres were facile synthesized by mild- temperature post-synthesis H2O2 hydrothermal treatment of as-synthesized MCM-48. The results showed that H2O2 is indispensable for simultaneously removing organic templates and forming ordered bimodal mesoporous silica MCM-48 spheres. The bimodal mesoporous MCM-48 was characterized by X-ray diffraction, transmission electron micrographs, FT-IR, and N2 adsorption-desorption, and a possible mechanism was proposed for the formation of bimodal mesoporous MCM-48.
基金supported by the National Natural Science Foundation of China(21878143,21476106,21838004)Joint Re-search Fund for Overseas Chinese Scholars and Scholars in Hong Kong and Macao Young Scholars(21729601)+1 种基金the fund of State Key Laboratory of Materials-Oriented Chemical Engineering(ZK201702)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)~~
文摘Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-TiO2 were used as catalytic supports to load Pd nanoparticles for H2 O2 direct synthesis from H2 and O2. The as-prepared samples were systematically studied by transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), air isothermal microcalorimeter, temperature-programmed reduction of H2(H2-TPR), and so on. The catalytic results showed that H2 O2 productivity and H2O2 selectivity of Pd/C-TiO2 firstly rose with increasing carbon content and then declined. Pd/C-TiO2 catalyst with 1.89 wt% of carbon content showed the best catalytic performance that had 61.2% of selectivity and 2192 mmol H2O2/g Pd/h of productivity, which were significantly better than those of pristine Pd/TiO2(45.2% and 1827 mmol H2O2/g Pd/h). Various characterization results displayed that the carbon species were heterogeneously dispersed on TiO2 surface. Moreover, no obvious geometric transformation in supports and Pd nanoparticles were observed among different catalysts. The superficial hydrophobicity of Pd/C-TiO2 was gradually promoted with increasing carbon content, which led to the corresponding decrease in adsorption energy of H2O2 with catalysts. According to structure-performance relationship analyses, the heterogeneous interfacial engineering of carbon could maintain the interaction of Pd nanoparticles with TiO2 and simultaneously accelerate the H2O2 desorption. Both factors further determined the excellent H2O2 direct synthesis performance of Pd/C-TiO2.
基金supported by the National Natural Science Foundation of China(No.51908536)the Ministry of Science and Technology of China(No.2018YFE0204103)。
文摘The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.
基金Supported by the National Natural Science Foundation of China(81573102 and 81273006)the Natural Science Fund Projects of Shaanxi Province(2017JM812)
文摘Objective To identify the osteogenesis genes whose expression is altered in hypertrophic chondrocytes treated with H2 O2.Methods Murine chondrogenitor cells(ATDC5) were differentiated into hypertrophic chondrocytes by InsulinTransferrin-Selenium(ITS) treatment, and then treated with H2 O2. Suitable conditions(concentration, time) were determined by using the MTT assay. After total RNA isolation and cD NA synthesis, the levels of 84 genes were determined using the PCR array, whereas quantitative RT-PCR was carried out to validate the PCR array data. Results We identified 9 up-regulated genes and 12 down-regulated genes, encoding proteins with various functions, such as collagen proteins, transcription factors, proteins involved in skeletal development and bone mineral metabolism, as well as cell adhesion molecules. Quantitative RT-PCR confirmed the altered expression of 5 down-regulated genes(Smad2, Smad4, transforming growth factor β receptor 1, transforming growth factor β receptor 3, and matrix metalloproteinase 10). Conclusions H2 O2 significantly changed the expression of several genes involved in a variety of biological functions. Because of the link between oxidative damage and Kashin-Beck disease, these genes may also be involved in the deep-zone necrosis of the cartilage observed in Kashin-Beck disease.
基金This study was supported by the funds from the Singapore Ministry of Education Academic Research Fund,Tier 1:RG111/15 and RG10/16 and Tier 2:MOE2016-T2-2 to 004.
文摘Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.
基金financially supported by the National Natural Science Foundation of China(NSFC)(Nos.51671003,21802003,21571112)Natural Science Foundation of Shandong Province(ZR2018BB031)+3 种基金the Shandong Taishan Scholar Program(H.W.)the China Postdoctoral Science Foundation(No.2017M610022)the start-up supports from Peking UniversityYoung Thousand Talented Program。
文摘Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science.Especially,it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors.Herein,we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes(Co3O4/NCNTs)hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air.The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions.As sensor electrode,the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40μA(mmol/L)^-1 cm^-2,a linear range of 5.00μmol/L-11.00 mmol/L,and a detection limitation of 1μmol/L in H2O2 detection,and a good glucose detection performance with 5μmol/L.These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.
基金funded by the National Natural Science Foundation of China (Nos. 21605093, 21775082 and 21575074)the Special Foundation for Distinguished Taishan Scholar of Shandong Province (No. ts201511052)
文摘Development of sensitive biosensors for biocatalytic transformations monitoring is in high demand but remains a great challenge. It is ascribed to the current strategies that focused on the single metabolite detection, which may bring about the relatively low sensitivity and false diagnosis result. Herein, we report the design and fabrication of novel carbon dots(CDs) with strong orange light emission, pH and H2O2 dual-responsive characteristics. The fluorescence quenching of CDs by H+and H2O2 enables the highly sensitive detection of H+/H2O2-generating biocatalytic transformations. This is exemplified by the glucose oxidase-mediated catalytic oxidation reaction on glucose, in which H+and H2O2 would be formed. As compared to the case in which glucose is present, significant fluorescence reduction is detected, and the fluorescence intensity is negatively proportional to glucose concentration. Thus, highly sensitive detection of glucose was readily achieved with a detection limit down to 10.18 nmol/L. The prepared CDs not only realize the highly sensitive detection of glucose, but also allows the probing other substances by changing the enzymes, thus providing a versatile platform, and demonstrating good potential to be used for biocatalytic transformations effective monitoring.
基金support by Northwestern University through a gift from Dr.Warren Haug is greatly appreciated
文摘Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis from H2 and O2. Based on mechanistic information available mostly for liquid phase catalytic processes, feasible reaction mechanisms for such coupled reactions are proposed based on which desirable catalyst properties are identified. It is found that the surface-adsorbed oxygen bond is an important parameter for identifying desirable catalysts. Thermodynamics can be used to identify the types of organic oxidation reactions that can couple with water oxidation such that H2O2 formation becomes thermodynamically favorable. Reactions such as epoxidation of alkenes and selective oxidation of alkanes to alcohols cannot provide sufficient thermodynamic driving force, whereas oxidation of alcohols to aldehydes and to acids can. Finally, further research is suggested to identify catalytic properties important for H2O2 decomposition and for coupling selective oxidation of organic compounds to oxidation of H2O in order to facilitate development of H2O2 production coupled with selective organic oxidation.
基金Funded by the National Natural Science Foundation of China(No.21476177)。
文摘A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.
基金Supported by Shandong Provincial Natural Science Foundation(ZR2019QEE039)
文摘This study used a bioelectrochemical system (BES) to produce H2O2.Seven cycles after the addition of microorganisms,the BES started successfully and entered a stable operation period.During stable operation,the voltage was 581 mV,the COD removal efficiency at the anode was 85.39%,and the H 2O 2 mass concentration at the cathode was 0.5%.After the addition of 10% of graphite particles in the reaction chamber,the H2O2 production increased by 13%.After loading Pt-containing carbon black catalyst on the cathode,the H2O2 production increased by 34%.The mass concentration of H2O2 was 0.67% under the optimum process conditions of a cathode loaded with Pt-containing carbon black catalyst,pH=7,and dissolved oxygen of 8 mg/L.
