Here, we present an optimization of colorimetric determination of hydrogen peroxide content in plants using potassium iodide. Our method is based on a one step buffer (extraction and reaction) for the determination of...Here, we present an optimization of colorimetric determination of hydrogen peroxide content in plants using potassium iodide. Our method is based on a one step buffer (extraction and reaction) for the determination of H2O2 in different plant tissues and overcomes interference of soluble antioxidant and color background. A particular attention is paid to buffer pH shown to be tissue dependent. With this inexpensive microplate method, it is possible to analyze 12 experimental samples in about 45 min all in triplicates, with blanks, controls and standard curve.展开更多
Three kinds of Pt/alumina catalysts were prepared by impregnation-hydrogen reduction, impregnation-hydrazine reduction and electroless plating methods. Their differences in the structures, specific areas and particle ...Three kinds of Pt/alumina catalysts were prepared by impregnation-hydrogen reduction, impregnation-hydrazine reduction and electroless plating methods. Their differences in the structures, specific areas and particle sizes were characterized by XRD, BET and TEM, respectively. Furthermore, their catalytic activities for the hydrogen iodide （HI） decomposition were evaluated in a fixed bed reactor. The results show that the catalyst 5%Pt/Al2O3 prepared by the electroless plating has the optimum catalytic properties for HI decomposition owing to the high dispersion of the platinum nano-particles （〈5 nm） on the alumina supports.展开更多
Oxygen evolution reaction(OER)as a half-anodic reaction of water splitting hinders the overall reaction efficiency owing to its thermodynamic and kinetic limitations.Iodide oxidation reaction(IOR)with low thermodynami...Oxygen evolution reaction(OER)as a half-anodic reaction of water splitting hinders the overall reaction efficiency owing to its thermodynamic and kinetic limitations.Iodide oxidation reaction(IOR)with low thermodynamic barrier and rapid reaction kinetics is a promising alternative to the OER.Herein,we present a molybdenum disulfide(MoS_(2))electrocatalyst for a high-efficiency and remarkably durable anode enabling IOR.MoS_(2)nanosheets deposited on a porous carbon paper via atomic layer deposition show an IOR current density of 10 mA cm^(–2)at an anodic potential of 0.63 V with respect to the reversible hydrogen electrode owing to the porous substrate as well as the intrinsic iodide oxidation capability of MoS_(2)as confirmed by theoretical calculations.The lower positive potential applied to the MoS_(2)-based heterostructure during IOR electrocatalysis prevents deterioration of the active sites on MoS_(2),resulting in exceptional durability of 200 h.Subsequently,we fabricate a two-electrode system comprising a MoS_(2)anode for IOR combined with a commercial Pt@C catalyst cathode for hydrogen evolution reaction.Moreover,the photovoltaic–electrochemical hydrogen production device comprising this electrolyzer and a single perovskite photovoltaic cell shows a record-high current density of 21 mA cm^(–2)at 1 sun under unbiased conditions.展开更多
Metal halide perovskites have emerged as novel and promising photocatalysts for hydrogen generation.Currently,their stability in water is a vital and urgent research question.In this paper a novel approach to stabiliz...Metal halide perovskites have emerged as novel and promising photocatalysts for hydrogen generation.Currently,their stability in water is a vital and urgent research question.In this paper a novel approach to stabilize a bismuth halide perovskite[(CH_(3))_(2)NH_(2)]_(3)[Bil_(6)](DA_(3)Bil_(6))in water using dimethylammonium iodide(DAI)without the assistance of acids or coatings is reported.The DA3Bil6 powder exhibits good stability in DAI solutions for at least two weeks.The concentration of DAI is found as a critical parameter,where the I^(-)ions play the key role in the stabilization.The stability of DA3Bil6 in water is realized via a surface dissolution-recrystallization process.Stabilized DA3Bil6 demonstrates constant photocatalytic properties for visible light-induced photo-oxidation of I^(-)ions and with PtCI4 as a co-catalyst(Pt-DA_(3)Bil_(6)),photocatalytic H2 evolution with a rate of 5.7μmol·h^(-1)from HI in DAI solution,obtaining an apparent quantum efficiency of 0.83%at 535 nm.This study provides new insights on the stabilization of metal halide perovskites for photocatalysis in aqueous solution.展开更多
Addition of fluoroalkyl iodides to olefins in the presence of hydrogen peroxide(H_2O_(?)) in acetone,acetonitrile or ethanol gave the corresponding 1:1 adducts in good yields.Reaction of fluoroalkyl iodide with dially...Addition of fluoroalkyl iodides to olefins in the presence of hydrogen peroxide(H_2O_(?)) in acetone,acetonitrile or ethanol gave the corresponding 1:1 adducts in good yields.Reaction of fluoroalkyl iodide with diallyl ether(DAE)yielded tetrahydrofuran derivatives,p-Hydroquinone (p-HQ)can partly suppress the reaction.A radical initiation mechanism is proposed.展开更多
为观察复方过氧化氢消毒剂杀菌作用及对室内空气消毒效果,采用定量杀菌试验和现场消毒试验方法,进行了实验研究。结果,以含2500 mg/L过氧化氢与2500 mg/L碘化钾组成的复方消毒剂,对悬液内大肠杆菌和金黄色葡萄球菌作用5 m in,杀灭率均为...为观察复方过氧化氢消毒剂杀菌作用及对室内空气消毒效果,采用定量杀菌试验和现场消毒试验方法,进行了实验研究。结果,以含2500 mg/L过氧化氢与2500 mg/L碘化钾组成的复方消毒剂,对悬液内大肠杆菌和金黄色葡萄球菌作用5 m in,杀灭率均为100%。以含5000 mg/L过氧化氢与5000 mg/L碘化钾组成的复方消毒剂,按每8 m l/m3的该复方消毒剂对室内空气中人工污染的金黄色葡萄球菌、大肠杆菌、绿脓杆菌进行气溶胶喷雾,密闭作用30 m in,杀灭率均达到99.99%。用该复方消毒剂进行气溶胶喷雾对医院普通手术室等房间内空气中自然菌作用30 m in,杀灭率达到96%以上。结论,复方过氧化氢消毒剂具有较强的杀菌作用,用气溶胶喷雾方法对室内空气中自然菌杀灭效果可达到消毒合格要求。展开更多
文摘Here, we present an optimization of colorimetric determination of hydrogen peroxide content in plants using potassium iodide. Our method is based on a one step buffer (extraction and reaction) for the determination of H2O2 in different plant tissues and overcomes interference of soluble antioxidant and color background. A particular attention is paid to buffer pH shown to be tissue dependent. With this inexpensive microplate method, it is possible to analyze 12 experimental samples in about 45 min all in triplicates, with blanks, controls and standard curve.
基金the Foundational Research Project of National Defence(No.A1420080145)for thefinancial support.
文摘Three kinds of Pt/alumina catalysts were prepared by impregnation-hydrogen reduction, impregnation-hydrazine reduction and electroless plating methods. Their differences in the structures, specific areas and particle sizes were characterized by XRD, BET and TEM, respectively. Furthermore, their catalytic activities for the hydrogen iodide （HI） decomposition were evaluated in a fixed bed reactor. The results show that the catalyst 5%Pt/Al2O3 prepared by the electroless plating has the optimum catalytic properties for HI decomposition owing to the high dispersion of the platinum nano-particles （〈5 nm） on the alumina supports.
基金the National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Grant Nos.2021R1A3B10689202021M3H4A1A03049662)+1 种基金the Materials and Components Technology Development Program of MOTIE/KEIT(10080527)the Yonsei Signature Research Cluster Program of 2021(2021-22-0002)。
文摘Oxygen evolution reaction(OER)as a half-anodic reaction of water splitting hinders the overall reaction efficiency owing to its thermodynamic and kinetic limitations.Iodide oxidation reaction(IOR)with low thermodynamic barrier and rapid reaction kinetics is a promising alternative to the OER.Herein,we present a molybdenum disulfide(MoS_(2))electrocatalyst for a high-efficiency and remarkably durable anode enabling IOR.MoS_(2)nanosheets deposited on a porous carbon paper via atomic layer deposition show an IOR current density of 10 mA cm^(–2)at an anodic potential of 0.63 V with respect to the reversible hydrogen electrode owing to the porous substrate as well as the intrinsic iodide oxidation capability of MoS_(2)as confirmed by theoretical calculations.The lower positive potential applied to the MoS_(2)-based heterostructure during IOR electrocatalysis prevents deterioration of the active sites on MoS_(2),resulting in exceptional durability of 200 h.Subsequently,we fabricate a two-electrode system comprising a MoS_(2)anode for IOR combined with a commercial Pt@C catalyst cathode for hydrogen evolution reaction.Moreover,the photovoltaic–electrochemical hydrogen production device comprising this electrolyzer and a single perovskite photovoltaic cell shows a record-high current density of 21 mA cm^(–2)at 1 sun under unbiased conditions.
基金the Kvantum Institute Em erging Project at the University of Oulu and Academy of Finland ELECTRA-project(No.2430291511).We thank Raija Oilunkaniemi and idarkus Riihimaki for the help with XRD and ATR characterization,respectively.We are grateful to the staff from Centre for Material Analysis(University of Oulu)for the characterization.ELI-ALPS is supported by the European Union and co-flnanced by the European Regional Development Fund(No.GINOP-2.3.6-15-2015-00001).M.U.K.also acknow ledgesfundingfrom PaNOSC Europeanproject.
文摘Metal halide perovskites have emerged as novel and promising photocatalysts for hydrogen generation.Currently,their stability in water is a vital and urgent research question.In this paper a novel approach to stabilize a bismuth halide perovskite[(CH_(3))_(2)NH_(2)]_(3)[Bil_(6)](DA_(3)Bil_(6))in water using dimethylammonium iodide(DAI)without the assistance of acids or coatings is reported.The DA3Bil6 powder exhibits good stability in DAI solutions for at least two weeks.The concentration of DAI is found as a critical parameter,where the I^(-)ions play the key role in the stabilization.The stability of DA3Bil6 in water is realized via a surface dissolution-recrystallization process.Stabilized DA3Bil6 demonstrates constant photocatalytic properties for visible light-induced photo-oxidation of I^(-)ions and with PtCI4 as a co-catalyst(Pt-DA_(3)Bil_(6)),photocatalytic H2 evolution with a rate of 5.7μmol·h^(-1)from HI in DAI solution,obtaining an apparent quantum efficiency of 0.83%at 535 nm.This study provides new insights on the stabilization of metal halide perovskites for photocatalysis in aqueous solution.
基金This project was supported by the National Natural Science Foundation of China.
文摘Addition of fluoroalkyl iodides to olefins in the presence of hydrogen peroxide(H_2O_(?)) in acetone,acetonitrile or ethanol gave the corresponding 1:1 adducts in good yields.Reaction of fluoroalkyl iodide with diallyl ether(DAE)yielded tetrahydrofuran derivatives,p-Hydroquinone (p-HQ)can partly suppress the reaction.A radical initiation mechanism is proposed.
文摘为观察复方过氧化氢消毒剂杀菌作用及对室内空气消毒效果,采用定量杀菌试验和现场消毒试验方法,进行了实验研究。结果,以含2500 mg/L过氧化氢与2500 mg/L碘化钾组成的复方消毒剂,对悬液内大肠杆菌和金黄色葡萄球菌作用5 m in,杀灭率均为100%。以含5000 mg/L过氧化氢与5000 mg/L碘化钾组成的复方消毒剂,按每8 m l/m3的该复方消毒剂对室内空气中人工污染的金黄色葡萄球菌、大肠杆菌、绿脓杆菌进行气溶胶喷雾,密闭作用30 m in,杀灭率均达到99.99%。用该复方消毒剂进行气溶胶喷雾对医院普通手术室等房间内空气中自然菌作用30 m in,杀灭率达到96%以上。结论,复方过氧化氢消毒剂具有较强的杀菌作用,用气溶胶喷雾方法对室内空气中自然菌杀灭效果可达到消毒合格要求。
