High-temperature thermal oxidation of an Fe foil produces a high-quality,crystalline hematite nanoflake suitable as a photoanode for the photoelectrochemical(PEC)water oxidation.Physical pre-polishing of the foil surf...High-temperature thermal oxidation of an Fe foil produces a high-quality,crystalline hematite nanoflake suitable as a photoanode for the photoelectrochemical(PEC)water oxidation.Physical pre-polishing of the foil surface has a profound effect in the formation of a vertically-aligned nanoflakes of hematite phase with extended(110)planes by removing the loosely-bonded oxide layer.When the surface of the photoanode is modified with a ZrO_(2) passivation layer and a cobalt phosphate co-catalyst,the charge recombination at the photoanode-electrolyte interface is greatly suppressed to improve its overall PEC activity.As a result,the photocurrent density at 1.10 VRHE under 1 sun condition is enhanced from 0.22 mA cm^(-2) for an unmodified photoanode to 0.59 mA cm^(-2) for the fully modified photoanode,and the photocurrent onset potential is shifted cathodically by 400 mV.Moreover,the photoanode demonstrates outstanding stability by showing steady production of H_(2) and O_(2) gases in the stoichiometric ratio of 2:1 in a continuous PEC operation for 10 h.展开更多
Abstract： Trivalent europium doped zinc oxide （ZnO：Eu3＋） nanocrystals were synthesized via room temperature chemical co-pre- cipitation and they were systematically characterized by means of X-ray diffraction （...Abstract： Trivalent europium doped zinc oxide （ZnO：Eu3＋） nanocrystals were synthesized via room temperature chemical co-pre- cipitation and they were systematically characterized by means of X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR） and photoluminescence （PL） spectroscopy. The as-synthesized samples were found to have hexagonal wurtzite coexisted with the intermediate Zn5（OH）sC12·H2O phase, while the single hexagonal phase was facilitated due to the calcinations. The as obtained samples were broadly composed ofnanoflakes while the highly crystalline nanorods were formed due to low temperature annealing of the as-synthesized samples. The crystallite size of the nanoflakes and nanorods （40-90 nm） were extracted from the XRD pattern which was found to be consistent with scanning electron microscopy （SEM） measurements. The photoluminescence （PL） spectra of nanophosphors showed bright red and orange emissions at 618 and 594 nm respectively with efficient broad blue green emis- sion spectrum due to ZnO lattice. Further, a good energy transfer process from ZnO host to Eu3＋ was observed in PL emission and excitation spectra of Eu3＋ doped ZnO ions. In all, the present nanophosphors were found to have great potentiality for bio-appli- cations.展开更多
用均匀沉淀法制备了片状复合氧化镍 NiMO（M = Li，Sr，Y，Fe，La）催化剂，并研究了其对乙烷氧化脱氢制乙烯的催化性能.采用 X 射线衍射（XRD）、扫描电子显微镜（SEM）、程序升温还原（H2-TPR）和程序升温脱附（O2-TPD）等方法对镍基...用均匀沉淀法制备了片状复合氧化镍 NiMO（M = Li，Sr，Y，Fe，La）催化剂，并研究了其对乙烷氧化脱氢制乙烯的催化性能.采用 X 射线衍射（XRD）、扫描电子显微镜（SEM）、程序升温还原（H2-TPR）和程序升温脱附（O2-TPD）等方法对镍基催化剂进行了表征. X 射线衍射和扫描电子显微镜检测结果表明：助剂的加入对催化剂的形貌影响不大，仍为片状结构；平均粒径为5~10 nm.程序升温还原和脱附表征结果表明：助剂 Li，Sr并未进入 NiO 晶格；而助剂 Y，Fe，La 与 Ni 之间具有相互作用，因而影响催化剂的理化性质和催化活性.其中， Fe 掺杂的片状氧化镍催化剂对乙烯的选择性和收率均有所改善，340℃时 NiFeO 催化剂上的乙烯收率可达18.2%.展开更多
This paper introduces a facile surfactant-free method for fabrication of different types of Ni-based nanostructures including metallic nickel nanoparticles (MNNP), nickel oxide nanoparticles (NONP) and chip-like nicke...This paper introduces a facile surfactant-free method for fabrication of different types of Ni-based nanostructures including metallic nickel nanoparticles (MNNP), nickel oxide nanoparticles (NONP) and chip-like nickel oxide nanoflakes (CNONF) by solvothermal technique at 190°C. Nickel acetyl acetonate (Ni(ac ac)2) was used as nickel precursor for both MNNP and CNONF and NiCO3●2Ni(OH)2●nH2O was utilized for NONP. Organic alcohols including 1-hexanol and benzyl alcohol were used as solvent to produce all powders. The crystallite sizes of MNNP, NONP and CNONF were determined by X-ray diffraction (XRD) to be 30, 9 and 27 nm, respectively. Electron microscopy indicated final particle sizes of 80 nm and 20 nm for MNNP and NONP, respectively and a thickness-layer less than 90 nm for CNONF. Brunauer-Emmett-Teller (BET) experiment determined a high surface area of 68 m2/gr for CNONF.展开更多
Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as...Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as a support to immobilize the active Pt component(Pt/NiMoO4)for catalytic formaldehyde elimination at low ambient temperature(15℃).The results showed that the hydrothermal preparation temperature and time had a noticeable impact on the morphology and catalytic activity of the samples.The catalyst prepared with hydrothermal temperature of 150℃for 4 hr(Pt-150-4)exhibited superior catalytic activity and stability mainly due to its distinctly porous structure,relative abundance of adsorbed surface hydroxyls/water,and high oxidation ability,which resulted from the interaction of Pt with Ni and Mo of the bimetallic NiMoO4 support.Our results might shed light on the rational design of multifunctional catalysts for removal of indoor air pollutants at low ambient temperature.展开更多
基金supported by the Climate Change Response Project(NRF-2019M1A2A2065612)the Basic Science Grant(NRF2019R1A4A1029237)+3 种基金Korea-China Key Joint Research Program(2017K2A9A2A11070341)funded by the Ministry of Science and ICTthe 2019 Research Fund(1.190013.01)of UNISTsupport by the Basic Science Research Programs through the National Public Technology Program based on Environmental Policy(2014000160001)the SRC program through the National Research Foundation of Korea(NRF2015R1A5A1009962)。
文摘High-temperature thermal oxidation of an Fe foil produces a high-quality,crystalline hematite nanoflake suitable as a photoanode for the photoelectrochemical(PEC)water oxidation.Physical pre-polishing of the foil surface has a profound effect in the formation of a vertically-aligned nanoflakes of hematite phase with extended(110)planes by removing the loosely-bonded oxide layer.When the surface of the photoanode is modified with a ZrO_(2) passivation layer and a cobalt phosphate co-catalyst,the charge recombination at the photoanode-electrolyte interface is greatly suppressed to improve its overall PEC activity.As a result,the photocurrent density at 1.10 VRHE under 1 sun condition is enhanced from 0.22 mA cm^(-2) for an unmodified photoanode to 0.59 mA cm^(-2) for the fully modified photoanode,and the photocurrent onset potential is shifted cathodically by 400 mV.Moreover,the photoanode demonstrates outstanding stability by showing steady production of H_(2) and O_(2) gases in the stoichiometric ratio of 2:1 in a continuous PEC operation for 10 h.
基金National Natural Science Foundation of China(21401073)Youth Foundation of Jilin Science and Technology(20140520097JH)Doctoral Foundation of Jilin Institute of Chemical Technology(2014161)
文摘Abstract： Trivalent europium doped zinc oxide （ZnO：Eu3＋） nanocrystals were synthesized via room temperature chemical co-pre- cipitation and they were systematically characterized by means of X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR） and photoluminescence （PL） spectroscopy. The as-synthesized samples were found to have hexagonal wurtzite coexisted with the intermediate Zn5（OH）sC12·H2O phase, while the single hexagonal phase was facilitated due to the calcinations. The as obtained samples were broadly composed ofnanoflakes while the highly crystalline nanorods were formed due to low temperature annealing of the as-synthesized samples. The crystallite size of the nanoflakes and nanorods （40-90 nm） were extracted from the XRD pattern which was found to be consistent with scanning electron microscopy （SEM） measurements. The photoluminescence （PL） spectra of nanophosphors showed bright red and orange emissions at 618 and 594 nm respectively with efficient broad blue green emis- sion spectrum due to ZnO lattice. Further, a good energy transfer process from ZnO host to Eu3＋ was observed in PL emission and excitation spectra of Eu3＋ doped ZnO ions. In all, the present nanophosphors were found to have great potentiality for bio-appli- cations.
文摘用均匀沉淀法制备了片状复合氧化镍 NiMO（M = Li，Sr，Y，Fe，La）催化剂，并研究了其对乙烷氧化脱氢制乙烯的催化性能.采用 X 射线衍射（XRD）、扫描电子显微镜（SEM）、程序升温还原（H2-TPR）和程序升温脱附（O2-TPD）等方法对镍基催化剂进行了表征. X 射线衍射和扫描电子显微镜检测结果表明：助剂的加入对催化剂的形貌影响不大，仍为片状结构；平均粒径为5~10 nm.程序升温还原和脱附表征结果表明：助剂 Li，Sr并未进入 NiO 晶格；而助剂 Y，Fe，La 与 Ni 之间具有相互作用，因而影响催化剂的理化性质和催化活性.其中， Fe 掺杂的片状氧化镍催化剂对乙烯的选择性和收率均有所改善，340℃时 NiFeO 催化剂上的乙烯收率可达18.2%.
基金supported by the National Nature Science Foundations of China (Grant No. 21673263, and 51572247)the Shandong Province Natural Science Foundation (Grant No. ZR2014EMM003)the Independent Innovation Plan Foundations of Qingdao City of China (Grant No. 16-5-1-42-jch)
文摘This paper introduces a facile surfactant-free method for fabrication of different types of Ni-based nanostructures including metallic nickel nanoparticles (MNNP), nickel oxide nanoparticles (NONP) and chip-like nickel oxide nanoflakes (CNONF) by solvothermal technique at 190°C. Nickel acetyl acetonate (Ni(ac ac)2) was used as nickel precursor for both MNNP and CNONF and NiCO3●2Ni(OH)2●nH2O was utilized for NONP. Organic alcohols including 1-hexanol and benzyl alcohol were used as solvent to produce all powders. The crystallite sizes of MNNP, NONP and CNONF were determined by X-ray diffraction (XRD) to be 30, 9 and 27 nm, respectively. Electron microscopy indicated final particle sizes of 80 nm and 20 nm for MNNP and NONP, respectively and a thickness-layer less than 90 nm for CNONF. Brunauer-Emmett-Teller (BET) experiment determined a high surface area of 68 m2/gr for CNONF.
基金supported by the National Natural Science Foundation of China(Nos.21577046 and 21871111)Wuhan Morning Light plan of Youth Science and Technology(No.2017050304010327)
文摘Efficient removal of formaldehyde from indoor environments is of significance for human health.In this work,a typical binary transition metal oxide that could provide various oxidation states,β-NiMoO4,was employed as a support to immobilize the active Pt component(Pt/NiMoO4)for catalytic formaldehyde elimination at low ambient temperature(15℃).The results showed that the hydrothermal preparation temperature and time had a noticeable impact on the morphology and catalytic activity of the samples.The catalyst prepared with hydrothermal temperature of 150℃for 4 hr(Pt-150-4)exhibited superior catalytic activity and stability mainly due to its distinctly porous structure,relative abundance of adsorbed surface hydroxyls/water,and high oxidation ability,which resulted from the interaction of Pt with Ni and Mo of the bimetallic NiMoO4 support.Our results might shed light on the rational design of multifunctional catalysts for removal of indoor air pollutants at low ambient temperature.
