The interface mechanism between catalyst and carbon substrate has been the focus of research.In this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple ...The interface mechanism between catalyst and carbon substrate has been the focus of research.In this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple one-step pyrolysis strategy.The experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electron transfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon material.The FeCo/SNC catalysts show outstanding performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).FeCo/S-NC shows a high half-wave potential(E_(1/2)=0.8823 V)for ORR and a low overpotential at 10 mA cm^(-2)(E_(j=10)=299 mV)for OER.In addition,compared with Pt/C+RuO_(2) assembled Zn-air battery(ZAB),the FeCo/S-NC assembled ZAB exhibits a larger power density(198.8 mW cm^(-2)),a higher specific capacity(786.1 mA h g_(zn)~(-1)),and ultra-stable cycle performance.These results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergistically enhance the electrochemical performance.展开更多
The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexame...The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.展开更多
Li_(5)Cr_(7)Ti_(6)O_(25) is regarded as a promising anode material for Li-ion batteries(LIBs)because of its low cost and high theoretical capacity.However,the inherently poor conductivity significantly limits the enha...Li_(5)Cr_(7)Ti_(6)O_(25) is regarded as a promising anode material for Li-ion batteries(LIBs)because of its low cost and high theoretical capacity.However,the inherently poor conductivity significantly limits the enhancement of its rate capability and cycling stability,especially at high current densities.In this work,we construct one-dimensional Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers by electrospinning method to enhance the kinetic,which realizes high cycling stability.Carbon coating enhances the structure stability,insertion/extraction reversibility of Li-ions and electrochemical reaction activity,and facilitates the transfer of Li-ions.Benefited from the unique architecture and component,the Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows an excellent rate capability with a reversible de-lithiation capacity of 370.8,290.6,269.2,254.3 and 244.9 m Ah g^(-1) at 200,300,500,800 and 1000 m A g^(-1),respectively.Even at a higher current density of 1 A g^(-1),Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows high cycling stability with an initial de-lithiation capacity of 237.8 m Ah g^(-1) and a capacity retention rate of about 84%after 500 cycles.The density functional theory calculation result confirms that the introduction of carbon on the surface of Li_(5)Cr_(7)Ti_(6)O_(25) changes the total density of states of Li_(5)Cr_(7)Ti_(6)O_(25),and thus improves electronic conductivity of the composite,resulting in a good electrochemical performance of Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers.Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers indicate a great potential as an anode material for the next generation of high-performance LIBs.展开更多
One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface ...One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface contact in the fabricated nanocomposite greatly influences the charge transfer and separation so as to determine the final photocatalytic activities.However,the role of interface contact is often neglected,and is rarely reported to date.Hence,it is possible to further enhance the photocatalytic activity of g‐C3N4‐based nanocomposite by improving the interfacial connection.Herein,phosphate-oxygen(P-O)bridged TiO2/g‐C3N4nanocomposites were successfully synthesized using a simple wet chemical method,and the effects of the P-O functional bridges on the photogenerated charge separation and photocatalytic activity for pollutant degradation and CO2reduction were investigated.The photocatalytic activity of g‐C3N4was greatly improved upon coupling with an appropriate amount of nanocrystalline TiO2,especially with P-O bridged TiO2.Atmosphere‐controlled steady‐state surface photovoltage spectroscopy and photoluminescence spectroscopy analyses revealed clearly the enhancement of photogenerated charge separation of g‐C3N4upon coupling with the P-O bridged TiO2,resulting from the built P-O bridges between TiO2and g‐C3N4so as to promote effective transfer of excited electrons from g‐C3N4to TiO2.This enhancement was responsible for the improved photoactivity of the P-O bridged TiO2/g‐C3N4nanocomposite,which exhibited three‐time photocatalytic activity enhancement for2,4‐dichlorophenol degradation and CO2reduction compared with bare g‐C3N4.Furthermore,radical‐trapping experiments revealed that the·OH species formed as hole‐modulated direct intermediates dominated the photocatalytic degradation of2,4‐dichlorophenol.This work provides a feasible strategy for the design and synthesis of high‐performance g‐C3N4‐based nanocomposite photocatalysts for pollutant degradation and CO2reduction.展开更多
The electrocatalytic oxidation of nitric oxide(NO) at a glass carbon electrode(GC) modified with functionalized single-walled carbon nanotubes(SWCNTs) was investigated by cyclic voltammetry(CV) and electrochem...The electrocatalytic oxidation of nitric oxide(NO) at a glass carbon electrode(GC) modified with functionalized single-walled carbon nanotubes(SWCNTs) was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS).It was found that the SWCNT modified electrode could speed greatly up the electron transfer rate compared with the bare GC electrode.After the SWCNT was treated with alkali or mixed acids,the reaction rate and activation energy of NO electrooxidation were changed to different extent.Chemical modification of the SWCNT surface is one of the most powerful methods to change the sensitivity of NO electrooxidation reaction.The modified electrode with SWCNT obtained by the firstly alkali treatment and then the mixed acids treatment was the best one for NO electrooxidation,the result of CV was also confirmed by that of EIS.The anodic processes of NO were recognized more clearly by exploring the reaction mechanism of NO electrooxidation at the SWCNT modified electrode.展开更多
Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)...Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.展开更多
Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optim...Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise.Here,we have designed a threedimensional(3D)hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a onepot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process.The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07°and an underwater bubble contact angle of 155.7°,thus facilitating an escape of bubbles from the electrodes.Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN,which can promote the adsorption/desorption of reactants and intermediates.The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at10 mA cm^(-2).The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm^(-2),which is approximately 209 mV lower than water electrolysis.展开更多
A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in th...A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in this study.Specifically,Co-MOF as an electron donor is capable of transferring the photogenerated electrons in the lowest unoccupied molecular orbital(LUMO)to the conduction band of g-C3N4 to facilitate charge separation.As expected,the prepared Co-MOF/g-C3N4 nanocomposites display excellent visible-light-driven photocatalytic CO2 reduction activities.The CO production rate of 6.75μmol g–1 h–1 and CH4 evolution rate of 5.47μmol g–1 h–1 are obtained,which are approximately 2 times those obtained with the original g-C3N4 under the same conditions.Based on a series of analyses,it is shown that the introduction of Co-MOF not only broadens the range of visible-light absorption but also enhances the charge separation,which improves the photocatalytic activity of g-C3N4 to a higher level.In particular,the hydroxyl radical(·OH)experiment was operated under 590 nm(single-wavelength)irradiation,which further proved that the photogenerated electrons in the LUMO of Co-MOF can successfully migrate to g-C3N4.This work may provide an important strategy for the design of highly efficient g-C3N4-based photocatalysts for CO2 reduction.展开更多
It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic r...It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic recyclable adsorbent of BiFeO3/Carbon nanocomposites for purifying simulative industrial dye wastewater. It is found that the structure of the prepared BiFeO3/Carbon nanocomposite is related to the natural structure of the biscuit, annealing temperatures and immersing times, demonstrated by XRD, TEM, UV-Vis and adsorptive activities. Kinetics data shows that the adsorption rate of the adsorbent to the dye is rapid and fitted well with the pseudo-second-order model, that more than 80% of dyes can be removed in the beginning 30 min. The adsorption isotherm can be perfectly described by the Langmuir model as well. It can be seen from the adsorption data that the adsorption performance can reach over 90% at pH ? 2–12, which can imply its universal utilization. The prepared BiFeO_3/Carbon nanocomposites have also displayed excellent capacities(over 90% within 30 min) for adsorption of seven different dyes and their mixed one. According to the five times photocatalytic reproducible experiments, it is proved that BiFeO_3/Carbon nanocomposites show the excellent stability and reproduction for purifying simulative industrial dyes, even the sample have been placed for one year. These research results indicate that the adsorbent BiFeO_3/Carbon can be a suitable material used in treating industrial dye wastewater potentially.展开更多
The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to ...The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to efficient charge transfer,the abundance of catalytic sites,and extended light absorption.Herein,an S‐scheme heterojunction of 2D/2D zinc porphyrin‐based metal‐organic frameworks/BiVO_(4)nanosheets(Zn‐MOF/BVON)was fabricated for efficient photocatalytic CO_(2)conversion.The optimal one shows a 22‐fold photoactivity enhancement when compared to the previously reported BiVO4 nanoflake(ca.15 nm),and even exhibits~2‐time improvement than the traditional g‐C3N4/BiVO4 heterojunction.The excellent photoactivities are ascribed to the strengthened S‐scheme charge transfer and separation,promoted CO_(2)activation by the well‐dispersed metal nodes Zn_(2)(COO)_(4)in the Zn‐MOF,and extended visible light response range based on the results of the electrochemical reduction,electron paramagnetic resonance,and in‐situ diffuse reflectance infrared Fourier transform spectroscopy.The dimension‐matched Zn‐MOF/BVON S‐scheme heterojunction endowed with highly efficient charge separation and abundant catalytic active sites contributed to the superior CO2 conversion.This study offers a facile strategy for constructing S‐scheme heterojunctions involving porphyrin‐based MOFs for solar fuel production.展开更多
lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synt...lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synthesized by a low-temperature hydrothermal method using a tai-lored diquaternary ammonium surfactant as the structure-directing agent.Introducing Ni^2+cationsat the ion-exchange sites of the TS-1 NS framework significantly enhanced its photoactivity in aero-bic alcohol oxidation.The optimized Ni cation-functionalized TS-1 NS(Ni/TS-1 NS)provide impres-sive photoactivity,with a benzyl alcohol(BA)conversion of 78.9%and benzyl aldehyde(BAD)se-lectivity of 98.8%using O as the only oxidant under full light irradiation;this BAD yield is approx-imately six times greater than that obtained for bulk TS-1,and is maintained for five runs.The ex-cellent photoactivity of Ni/TS-1 NS is attributed to the significantly enlarged surface area of thetwo-dimensional morphology TS-1 NS,extra mesopores,and greatly improved charge separation.Compared with bulk TS-1,Ni/TS-1 NS has a much shorter charge transfer distance.Theas-introduced Ni species could capture the photoelectrons to further improve the charge separa-tion.This work opens the way to a class of highly selective,robust,and low-cost titanosilicate mo-lecular sieve-based photocatalysts with industrial potential for selective oxidative transformationsand pollutant degradation.展开更多
In this work,the hierarchical CoNiO_(2)@CeO_(2)nanosheet composites were successfully prepared by a one-step hydrothermal process with a subsequent annealing process for the first time.The CeO_(2)nanoparticles success...In this work,the hierarchical CoNiO_(2)@CeO_(2)nanosheet composites were successfully prepared by a one-step hydrothermal process with a subsequent annealing process for the first time.The CeO_(2)nanoparticles successfully deposit on the surface of CoNiO_(2)nanosheet,and benefit the improvement of electrical contact between CoNiO_(2)and CeO_(2).CeO_(2)modification improve the reversibility of insertion/extraction of Li-ions and electrochemical reaction activity,and promotes the transport of Li-ions.Benefited of the unique architecture and component,the CoNiO_(2)@CeO_(2)nanosheet composites show high-reversible capacities,excellent cycling stability and good rate capability.The CoNiO_(2)@CeO_(2)(5.0 wt%)shows a charge/discharge capacity of 867.1/843.2 m Ah g^(-1)after 600 cycles at 1 A g^(-1),but the pristine CoNiO_(2)@CeO_(2)nanosheet only delivers a charge/discharge capacity of 516.9/517.6 m Ah g^(-1)after 500 cycles.The first-principles calculation reveals that valid interfaces between CeO_(2)and NiCoO_(2)can be formed,and the formation process of the interfaces is exothermic.The strong interfacial interaction resulting in an excellent structure stability and thus a cycling stability of the CoNiO_(2)@CeO_(2)material.This work provides an effective strategy to develop highperformance anode materials for advanced a lithium-ion battery,and the CoNiO_(2)@CeO_(2)nanosheet shows a sizeable potential as an anode material for next generation of high-energy Li-ion batteries.展开更多
The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indica...The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indicate that the adsorption of alkali metal on the center site of a CNT tip is energetically favorable.In addition,the adsorption energies increase with the introduction of the electric field.The excessive negative charges on CNT tips make electron emittance much easier and result in a decrease in work function.Furthermore,the inducing effect by positively charged alkali metal atoms can be reasonably considered as the dominant reason for the improvement in field emission properties.展开更多
A novel thiosemicarbazide derivative, (E)-1-(9-(2-(2-methoxyethoxy)ethyl)-9H-carbazol-3-yl) methylene)-thiosemicarbazide (CMT), was synthesized and structurally characterized by IR, 1H-NMR, EI-MS and single...A novel thiosemicarbazide derivative, (E)-1-(9-(2-(2-methoxyethoxy)ethyl)-9H-carbazol-3-yl) methylene)-thiosemicarbazide (CMT), was synthesized and structurally characterized by IR, 1H-NMR, EI-MS and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 14.769(5), b = 8.279(5), c = 17.166(5) , β = 114.391(5)°, V = 1911.6(14) 3, Z = 4, F(000) = 784, Dc = 1.287 g/m3, Mr = 370.47, μ = 0.190 mm-1, the final R = 0.0390 and wR = 0.1358 for 1446 observed reflections with Ⅰ 〉 2σ(Ⅰ). The UV-vis absorption spectra of CMT were explained based on quantum chemical calculations, using time dependent density functional theory (TD-DFT) at the B3LYP/6-31G (d) level.展开更多
The Zn(Ⅱ) phthalocyanine sensitized TiO2(ZnPc-TiO2) nanoparticles were prepared by hydrothermal method via impregnation with ZnPc.The as-prepared photocatalysts were characterized by X-ray diffractometry(XRD) and dif...The Zn(Ⅱ) phthalocyanine sensitized TiO2(ZnPc-TiO2) nanoparticles were prepared by hydrothermal method via impregnation with ZnPc.The as-prepared photocatalysts were characterized by X-ray diffractometry(XRD) and diffuse reflectance spectroscopy(DRS),and the surface photovoltage spectroscopy(SPS) and photocatalytic degradation of rhodamine B(RhB) were studied under illuminating.The experimental results indicate that TiO2 sensitized by ZnPc extends its absorption band into the visible region effectively,and the sensitized TiO2 has higher activity than TiO2(Degussa P-25) under the simulated solar light and the visible light.Based on the DRS and SPS results,the mechanism about the photogenerated carrier transfer between TiO2 and ZnPc is proposed.At a lower ZnPc content(≤0.20 μmol/g),ZnPc monomer acts as the electron donor,which provides the photoinduced electrons to the conduction band of TiO2.These photoinduced electrons can transfer to molecular oxygen(O2),leading to the formation of active species,such as superoxide/hydroxide radicals and singlet oxygen,which is beneficial to the photocatalytic reaction.While at a higher ZnPc content(>0.20 μmol/g),the formation of ZnPc dimer results in the decrease of photocatalytic activities of ZnPc-TiO2 photocatalyst.展开更多
Novel linear and star branched triphenylamine-containing aromatic imides were designed and synthesized by the condensation between amine-substituted triphenylamine and naphthalene-1, 4, 5, 8-tetra-carboxylic dianhydri...Novel linear and star branched triphenylamine-containing aromatic imides were designed and synthesized by the condensation between amine-substituted triphenylamine and naphthalene-1, 4, 5, 8-tetra-carboxylic dianhydride in order to investigate the influence of topological structure on the photophysical performance. The polyimides were characterized by elementary analysis and FTIR measurements. Thermogravimetric analysis (TGA) shows that the onset temperatures of decomposition (Td) for 5% mass loss range from 371 to 445 ℃. UV-Vis spectrum, quantum chemical calculation and cyclic voltammetry (CV) were used to obtain the dependence of energy levels on the function of structures. The introduction of triphenylamine group changes the energy level of the entire dye system. The dye-sensitized solar cells (DSSCs) prepared by using the dyes have a strong photoelectric current response in visible light region of 400-600 nm.展开更多
A novel pyrazole derivative ligand, BTA(BTA = bis-(4-ethoxy-phenyl)-[4-(tripyrazol-1-yl-methyl)-phenyl]-amine), was synthesized and fully characterized by 1H-NMR, MALDI-TOF-MS spectra and single-crystal X-ray di...A novel pyrazole derivative ligand, BTA(BTA = bis-(4-ethoxy-phenyl)-[4-(tripyrazol-1-yl-methyl)-phenyl]-amine), was synthesized and fully characterized by 1H-NMR, MALDI-TOF-MS spectra and single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1, with a = 11.827(1), b = 16.000(2), c = 16.527(2)A, α = 108.510(1), β = 91.116(5), γ = 101.734(1)°, V = 2894.5(6) A3, Z = 1, Dc = 1.262 g/m^3, F(000) = 1162, Μr = 545.63, μ = 0.083 mm-1, the final R = 0.0728 and w R = 0.2213 for 7541 observed reflections with I 〉 2(I). The structural analysis revealed that three pyrazole units are attached to the same carbon atom connected with bis-(4-ethoxy-phenyl)-phenyl-amine group. UV-vis spectral features of the ligand in various solutions were explained by time dependent density functional theory(TD-DFT). It was also found that the ligand(BTA) exhibits an exclusively selective and sensitive response toward Fe3+ using UV-vis spectroscopic method.展开更多
Fe(Ⅱ) was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%---4% HF to remove ...Fe(Ⅱ) was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%---4% HF to remove the SiO2 template and then calcined. It was found that nanowire bundles, dendritic plates of porous iron oxide, dense parallel backbones of porous iron oxide were obtained at -1.4-- -1.6 V and 0.08--0.1 mol/L electrolyte concentration after calcinations; the dendritic pattern of porous iron oxide film templated by the SBA-16 film was obtained in macrostructure at a higher absolute value of cathode potential(-1.7-- -1.8 V) and a lower electrolyte concentration(0.02-0.05 mol/L), the dendritic pattern of porous iron oxide film could copy the microstructure of SBA-16 film; Fe(II) nanowires grew and formed in one dimension(1D) and two-dimension(2D) electrocrystallization at a potential of-l.6-- -1.7 V and an electrolyte concentration of 0.05 mol/L, and the shape of the ID or 2D crystalline iron oxide nanowires calcined was similar to the original shape of the SBA-16 channels. The desired morphology and size of porous nanocrystal iron oxide can be obtained by adjusting the applied potential value and electrolyte concentration, and all kinds of morphologies of porous nanostructure crystal iron oxide can be prepared.展开更多
SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully prepared.The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity.Furthermo...SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully prepared.The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity.Furthermore,ZrO_(2)coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film.As a result,the redox polarization was reduced,and the reversibility of the electrochemical reaction was enhanced.Particularly,SLTO-ZrO_(2)-2 sample delivers a high initial lithiation capacity of 283.6 mA h g^(-1),and the values maintain at 251.7,228.0,207.4,175.3,and 147.7 mA h g^(-1)at the current densities of 0.13,0.26,0.54,1.31,and 2.62 A g^(-1),respectively.Our experiment also confirmed that SLTO materials coated with ZrO_(2)are suitable for high power density applications,and the lithiation specific energy efficiency of SLTO-ZrO_(2)-2 is 200%as high as that of pure SLTO at a power density of 1257 W kg^(-1).展开更多
To optimize the preparation process of chitosan microspheres and study its loading capacity, chitosan microsphere was prepared by crosslinking with glutaraldehyde, and bovine serum albumin (BSA) was absorbed onto ch...To optimize the preparation process of chitosan microspheres and study its loading capacity, chitosan microsphere was prepared by crosslinking with glutaraldehyde, and bovine serum albumin (BSA) was absorbed onto chitosan microsphere. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FITR), TA instruments and zeta potentiometer analyzer were used to characterize the parameters with respect to size, thermal characters, morphology, and zeta potential of the microspheres. The loading capability and in vitro release tests were carried out. The results showed that chitosan microsphere with particle size less than 10 μm and positively charged (+25.97±0.56 mV) can be obtained under the aldehyde group to amino group ratio at 1:1. A loading capacity of BSA at 28.63±0.15 g/100 g with corresponding loading efficiency at 72.01±1.44% was obtained for chitosan microsphere. In vitro test revealed a burst release followed by sustained-release profile.展开更多
基金supported by the National Natural Science Foundation of China(52374301 and 22279030)the Fundamental Research Funds for the Central Universities(N2223037)+1 种基金Hebei Key Laboratory of Dielectric and Electrolyte Functional Material,Northeastern University at Qinhuangdao(HKDEFM2021201)the Performance subsidy fund for the Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province(22567627H)。
文摘The interface mechanism between catalyst and carbon substrate has been the focus of research.In this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple one-step pyrolysis strategy.The experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electron transfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon material.The FeCo/SNC catalysts show outstanding performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).FeCo/S-NC shows a high half-wave potential(E_(1/2)=0.8823 V)for ORR and a low overpotential at 10 mA cm^(-2)(E_(j=10)=299 mV)for OER.In addition,compared with Pt/C+RuO_(2) assembled Zn-air battery(ZAB),the FeCo/S-NC assembled ZAB exhibits a larger power density(198.8 mW cm^(-2)),a higher specific capacity(786.1 mA h g_(zn)~(-1)),and ultra-stable cycle performance.These results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergistically enhance the electrochemical performance.
基金funded by the National Key Research and Development Project,Intergovernmental International Science and Technology Innovation Cooperation Key Project(No.2018YFE0108800)National Natural Science Foundation of China(No.22278115)Heilongjiang Province Natural Science Foundation(No.YQ2021B010).
文摘The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.
基金supported by the National Natural Science Foundation of China(U1960107)the“333”Talent Project of Hebei Province(A202005018)+1 种基金the Fundamental Research Funds for the Central Universities(N2123034 and N2123001)Hebei Key Laboratory of Dielectric and Electrolyte Functional Material,Northeastern University at Qinhuangdao(HKDEFM2021201)。
文摘Li_(5)Cr_(7)Ti_(6)O_(25) is regarded as a promising anode material for Li-ion batteries(LIBs)because of its low cost and high theoretical capacity.However,the inherently poor conductivity significantly limits the enhancement of its rate capability and cycling stability,especially at high current densities.In this work,we construct one-dimensional Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers by electrospinning method to enhance the kinetic,which realizes high cycling stability.Carbon coating enhances the structure stability,insertion/extraction reversibility of Li-ions and electrochemical reaction activity,and facilitates the transfer of Li-ions.Benefited from the unique architecture and component,the Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows an excellent rate capability with a reversible de-lithiation capacity of 370.8,290.6,269.2,254.3 and 244.9 m Ah g^(-1) at 200,300,500,800 and 1000 m A g^(-1),respectively.Even at a higher current density of 1 A g^(-1),Li_(5)Cr_(7)Ti_(6)O_(25)/C(6.6 wt%)nanofiber shows high cycling stability with an initial de-lithiation capacity of 237.8 m Ah g^(-1) and a capacity retention rate of about 84%after 500 cycles.The density functional theory calculation result confirms that the introduction of carbon on the surface of Li_(5)Cr_(7)Ti_(6)O_(25) changes the total density of states of Li_(5)Cr_(7)Ti_(6)O_(25),and thus improves electronic conductivity of the composite,resulting in a good electrochemical performance of Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers.Li_(5)Cr_(7)Ti_(6)O_(25)/C nanofibers indicate a great potential as an anode material for the next generation of high-performance LIBs.
基金supported by the National Natural Science Foundation of China(U1401245,91622119)the Program for Innovative Research Team in Chinese Universities(IRT1237)+1 种基金the Research Project of Chinese Ministry of Education(213011A)the Science Foundation for Excellent Youth of Harbin City of China(2014RFYXJ002)~~
文摘One of the most general methods to enhance the separation of photogenerated carriers for g‐C3N4is to construct a suitable heterojunctional composite,according to the principle of matching energy levels.The interface contact in the fabricated nanocomposite greatly influences the charge transfer and separation so as to determine the final photocatalytic activities.However,the role of interface contact is often neglected,and is rarely reported to date.Hence,it is possible to further enhance the photocatalytic activity of g‐C3N4‐based nanocomposite by improving the interfacial connection.Herein,phosphate-oxygen(P-O)bridged TiO2/g‐C3N4nanocomposites were successfully synthesized using a simple wet chemical method,and the effects of the P-O functional bridges on the photogenerated charge separation and photocatalytic activity for pollutant degradation and CO2reduction were investigated.The photocatalytic activity of g‐C3N4was greatly improved upon coupling with an appropriate amount of nanocrystalline TiO2,especially with P-O bridged TiO2.Atmosphere‐controlled steady‐state surface photovoltage spectroscopy and photoluminescence spectroscopy analyses revealed clearly the enhancement of photogenerated charge separation of g‐C3N4upon coupling with the P-O bridged TiO2,resulting from the built P-O bridges between TiO2and g‐C3N4so as to promote effective transfer of excited electrons from g‐C3N4to TiO2.This enhancement was responsible for the improved photoactivity of the P-O bridged TiO2/g‐C3N4nanocomposite,which exhibited three‐time photocatalytic activity enhancement for2,4‐dichlorophenol degradation and CO2reduction compared with bare g‐C3N4.Furthermore,radical‐trapping experiments revealed that the·OH species formed as hole‐modulated direct intermediates dominated the photocatalytic degradation of2,4‐dichlorophenol.This work provides a feasible strategy for the design and synthesis of high‐performance g‐C3N4‐based nanocomposite photocatalysts for pollutant degradation and CO2reduction.
基金Supported by the National Natural Science Foundation of China(Nos.20676027 and 21076066)the Postdoctoral Foundation of Heilongjiang Province,China(No.LBH-Q07111)
文摘The electrocatalytic oxidation of nitric oxide(NO) at a glass carbon electrode(GC) modified with functionalized single-walled carbon nanotubes(SWCNTs) was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS).It was found that the SWCNT modified electrode could speed greatly up the electron transfer rate compared with the bare GC electrode.After the SWCNT was treated with alkali or mixed acids,the reaction rate and activation energy of NO electrooxidation were changed to different extent.Chemical modification of the SWCNT surface is one of the most powerful methods to change the sensitivity of NO electrooxidation reaction.The modified electrode with SWCNT obtained by the firstly alkali treatment and then the mixed acids treatment was the best one for NO electrooxidation,the result of CV was also confirmed by that of EIS.The anodic processes of NO were recognized more clearly by exploring the reaction mechanism of NO electrooxidation at the SWCNT modified electrode.
基金supported by the National Natural Science Foundation of China(22279025,21773048)the Natural Science Foundation of Heilongjiang Province(LH2021A013)+1 种基金the Sichuan Science and Technology Program(2021YFSY0022)the Fundamental Research Funds for the Central Universities(2023FRFK06005,HIT.NSRIF202204)。
文摘Developing efficient and stable cathodes for low-temperature solid oxide fuel cells(LT-SOFCs) is of great importance for the practical commercialization.Herein,we propose a series of Sm-modified Bi_(0.7-x)Sm_xSr_(0.3)FeO_(3-δ) perovskites as highly-active catalysts for LT-SOFCs.Sm doping can significantly enhance the electrocata lytic activity and chemical stability of cathode.At 600℃,Bi_(0.675)Sm_(0.025)Sr_(0.3)FeO_(3-δ)(BSSF25) cathode has been found to be the optimum composition with a polarization resistance of 0.098 Ω cm^2,which is only around 22.8% of Bi_(0.7)Sr_(0.3)FeO_(3-δ)(BSF).A full cell utilizing BSSF25 displays an exceptional output density of 790 mW cm^(-2),which can operate continuously over100 h without obvious degradation.The remarkable electrochemical performance observed can be attributed to the improved O_(2) transport kinetics,superior surface oxygen adsorption capacity,as well as O_(2)p band centers in close proximity to the Fermi level.Moreover,larger average bonding energy(ABE) and the presence of highly acidic Bi,Sm,and Fe ions restrict the adsorption of CO_(2) on the cathode surface,resulting in excellent CO_(2) resistivity.This work provides valuable guidance for systematic design of efficient and durable catalysts for LT-SOFCs.
基金financially supported by the National Key R&D Program of China(2022YFA1503003)the National Natural Science Foundation of China(91961111,22271081)+3 种基金the Natural Science Foundation of Heilongjiang Province(ZD2021B003)the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(UNPYSCT-2020004)The Basic Research Fund of Heilongjiang University in Heilongjiang Province(2021-KYYWF-0039)the Heilongjiang University Excellent Youth Foundation。
文摘Hydrogen evolution reaction(HER)and urea oxidation reaction(UOR)are key reactions of the watercycling associated catalytic process/device.The design of catalysts with a super-hydrophilic/aerophobic structure and optimized electron distribution holds great promise.Here,we have designed a threedimensional(3D)hollow Ni/NiMoN hierarchical structure with arrayed-sheet surface based on a onepot hydrothermal route for efficient urea-assisted HER based on a simple hydrothermal process.The Ni/NiMoN catalyst exhibits super-hydrophilic/aerophobic properties with a small droplet contact angle of 6.07°and an underwater bubble contact angle of 155.7°,thus facilitating an escape of bubbles from the electrodes.Density functional theory calculations and X-ray photoelectron spectroscopy results indicate the optimized electronic structure at the interface of Ni and NiMoN,which can promote the adsorption/desorption of reactants and intermediates.The virtues combining with a large specific surface area endow Ni/NiMoN with efficient catalytic activity of low potentials of 25 mV for HER and 1.33 V for UOR at10 mA cm^(-2).The coupled HER and UOR system demonstrates a low cell voltage of 1.42 V at 10 mA cm^(-2),which is approximately 209 mV lower than water electrolysis.
基金supported by the National Natural Science Foundation of China(21871079,21501052)the Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province(YQ2019B006)~~
文摘A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride(g-C3N4)nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework(MOF)is proposed in this study.Specifically,Co-MOF as an electron donor is capable of transferring the photogenerated electrons in the lowest unoccupied molecular orbital(LUMO)to the conduction band of g-C3N4 to facilitate charge separation.As expected,the prepared Co-MOF/g-C3N4 nanocomposites display excellent visible-light-driven photocatalytic CO2 reduction activities.The CO production rate of 6.75μmol g–1 h–1 and CH4 evolution rate of 5.47μmol g–1 h–1 are obtained,which are approximately 2 times those obtained with the original g-C3N4 under the same conditions.Based on a series of analyses,it is shown that the introduction of Co-MOF not only broadens the range of visible-light absorption but also enhances the charge separation,which improves the photocatalytic activity of g-C3N4 to a higher level.In particular,the hydroxyl radical(·OH)experiment was operated under 590 nm(single-wavelength)irradiation,which further proved that the photogenerated electrons in the LUMO of Co-MOF can successfully migrate to g-C3N4.This work may provide an important strategy for the design of highly efficient g-C3N4-based photocatalysts for CO2 reduction.
基金financial support from the NSFC project(21501052 and 91622119)the China Postdoctoral Science Foundation(2015M570304)+2 种基金Special Funding for Postdoctoral of Heilongjiang Province(LBH-TZ06019)the Science Foundation for Excellent Youth of Harbin City of China(2016RQQXJ099)UNPYSCT-2016173
文摘It is essential to prepare highly-efficiency reproducible adsorbent for purifying industrial dye wastewater. In this work, biscuit with a layered porous structure as a template is applied to prepare a photocatalytic recyclable adsorbent of BiFeO3/Carbon nanocomposites for purifying simulative industrial dye wastewater. It is found that the structure of the prepared BiFeO3/Carbon nanocomposite is related to the natural structure of the biscuit, annealing temperatures and immersing times, demonstrated by XRD, TEM, UV-Vis and adsorptive activities. Kinetics data shows that the adsorption rate of the adsorbent to the dye is rapid and fitted well with the pseudo-second-order model, that more than 80% of dyes can be removed in the beginning 30 min. The adsorption isotherm can be perfectly described by the Langmuir model as well. It can be seen from the adsorption data that the adsorption performance can reach over 90% at pH ? 2–12, which can imply its universal utilization. The prepared BiFeO_3/Carbon nanocomposites have also displayed excellent capacities(over 90% within 30 min) for adsorption of seven different dyes and their mixed one. According to the five times photocatalytic reproducible experiments, it is proved that BiFeO_3/Carbon nanocomposites show the excellent stability and reproduction for purifying simulative industrial dyes, even the sample have been placed for one year. These research results indicate that the adsorbent BiFeO_3/Carbon can be a suitable material used in treating industrial dye wastewater potentially.
文摘The construction of S‐scheme heterojunction photocatalysts has been regarded as an effective avenue to facilitate the conversion of solar energy to fuel.However,there are still considerable challenges with regard to efficient charge transfer,the abundance of catalytic sites,and extended light absorption.Herein,an S‐scheme heterojunction of 2D/2D zinc porphyrin‐based metal‐organic frameworks/BiVO_(4)nanosheets(Zn‐MOF/BVON)was fabricated for efficient photocatalytic CO_(2)conversion.The optimal one shows a 22‐fold photoactivity enhancement when compared to the previously reported BiVO4 nanoflake(ca.15 nm),and even exhibits~2‐time improvement than the traditional g‐C3N4/BiVO4 heterojunction.The excellent photoactivities are ascribed to the strengthened S‐scheme charge transfer and separation,promoted CO_(2)activation by the well‐dispersed metal nodes Zn_(2)(COO)_(4)in the Zn‐MOF,and extended visible light response range based on the results of the electrochemical reduction,electron paramagnetic resonance,and in‐situ diffuse reflectance infrared Fourier transform spectroscopy.The dimension‐matched Zn‐MOF/BVON S‐scheme heterojunction endowed with highly efficient charge separation and abundant catalytic active sites contributed to the superior CO2 conversion.This study offers a facile strategy for constructing S‐scheme heterojunctions involving porphyrin‐based MOFs for solar fuel production.
文摘lmprovement of the charge separation of titanosilicate molecular sieves is critical to their use asphotocatalysts for oxidative organic transformations.In this work,MFI TS-1 molecular sievenanosheets(TS-1 NS)were synthesized by a low-temperature hydrothermal method using a tai-lored diquaternary ammonium surfactant as the structure-directing agent.Introducing Ni^2+cationsat the ion-exchange sites of the TS-1 NS framework significantly enhanced its photoactivity in aero-bic alcohol oxidation.The optimized Ni cation-functionalized TS-1 NS(Ni/TS-1 NS)provide impres-sive photoactivity,with a benzyl alcohol(BA)conversion of 78.9%and benzyl aldehyde(BAD)se-lectivity of 98.8%using O as the only oxidant under full light irradiation;this BAD yield is approx-imately six times greater than that obtained for bulk TS-1,and is maintained for five runs.The ex-cellent photoactivity of Ni/TS-1 NS is attributed to the significantly enlarged surface area of thetwo-dimensional morphology TS-1 NS,extra mesopores,and greatly improved charge separation.Compared with bulk TS-1,Ni/TS-1 NS has a much shorter charge transfer distance.Theas-introduced Ni species could capture the photoelectrons to further improve the charge separa-tion.This work opens the way to a class of highly selective,robust,and low-cost titanosilicate mo-lecular sieve-based photocatalysts with industrial potential for selective oxidative transformationsand pollutant degradation.
基金financially supported by the National Natural Science Foundation of China(nos.U1960107 and 21773060)Key Program for International S&T Cooperation Projects of China(no.2017YFE0124300)the Fundamental Research Funds for the Central Universities(no.N182304014)
文摘In this work,the hierarchical CoNiO_(2)@CeO_(2)nanosheet composites were successfully prepared by a one-step hydrothermal process with a subsequent annealing process for the first time.The CeO_(2)nanoparticles successfully deposit on the surface of CoNiO_(2)nanosheet,and benefit the improvement of electrical contact between CoNiO_(2)and CeO_(2).CeO_(2)modification improve the reversibility of insertion/extraction of Li-ions and electrochemical reaction activity,and promotes the transport of Li-ions.Benefited of the unique architecture and component,the CoNiO_(2)@CeO_(2)nanosheet composites show high-reversible capacities,excellent cycling stability and good rate capability.The CoNiO_(2)@CeO_(2)(5.0 wt%)shows a charge/discharge capacity of 867.1/843.2 m Ah g^(-1)after 600 cycles at 1 A g^(-1),but the pristine CoNiO_(2)@CeO_(2)nanosheet only delivers a charge/discharge capacity of 516.9/517.6 m Ah g^(-1)after 500 cycles.The first-principles calculation reveals that valid interfaces between CeO_(2)and NiCoO_(2)can be formed,and the formation process of the interfaces is exothermic.The strong interfacial interaction resulting in an excellent structure stability and thus a cycling stability of the CoNiO_(2)@CeO_(2)material.This work provides an effective strategy to develop highperformance anode materials for advanced a lithium-ion battery,and the CoNiO_(2)@CeO_(2)nanosheet shows a sizeable potential as an anode material for next generation of high-energy Li-ion batteries.
基金Project supported by the Key Program of the National Natural Science Foundation of China(Grant Nos.21031001 and U1034003)the National Natural Science Foundation of China(Grant Nos.20971040 and 21173072)the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China(Grant No.708029)
文摘The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indicate that the adsorption of alkali metal on the center site of a CNT tip is energetically favorable.In addition,the adsorption energies increase with the introduction of the electric field.The excessive negative charges on CNT tips make electron emittance much easier and result in a decrease in work function.Furthermore,the inducing effect by positively charged alkali metal atoms can be reasonably considered as the dominant reason for the improvement in field emission properties.
基金supported by the National Natural Science Foundation of China (51142011)Natural Science Foundation of Anhui Province (1208085MB22)Education Department of Anhui Province (KJ2010A030)
文摘A novel thiosemicarbazide derivative, (E)-1-(9-(2-(2-methoxyethoxy)ethyl)-9H-carbazol-3-yl) methylene)-thiosemicarbazide (CMT), was synthesized and structurally characterized by IR, 1H-NMR, EI-MS and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 14.769(5), b = 8.279(5), c = 17.166(5) , β = 114.391(5)°, V = 1911.6(14) 3, Z = 4, F(000) = 784, Dc = 1.287 g/m3, Mr = 370.47, μ = 0.190 mm-1, the final R = 0.0390 and wR = 0.1358 for 1446 observed reflections with Ⅰ 〉 2σ(Ⅰ). The UV-vis absorption spectra of CMT were explained based on quantum chemical calculations, using time dependent density functional theory (TD-DFT) at the B3LYP/6-31G (d) level.
基金Project(20431030) supported by the National Natural Science Foundation of ChinaProject(2006RFQXS096) supported by the Foundation for Science and Technology Innovation Talents of Harbin, China+1 种基金Project(1152Z002) supported by the Key Projects of Educational Department of Heilongjiang Province, ChinaProject(LBH-Q07111) supported by Heilongjiang Postdoctoral Funds for Scientific Research Initiation
文摘The Zn(Ⅱ) phthalocyanine sensitized TiO2(ZnPc-TiO2) nanoparticles were prepared by hydrothermal method via impregnation with ZnPc.The as-prepared photocatalysts were characterized by X-ray diffractometry(XRD) and diffuse reflectance spectroscopy(DRS),and the surface photovoltage spectroscopy(SPS) and photocatalytic degradation of rhodamine B(RhB) were studied under illuminating.The experimental results indicate that TiO2 sensitized by ZnPc extends its absorption band into the visible region effectively,and the sensitized TiO2 has higher activity than TiO2(Degussa P-25) under the simulated solar light and the visible light.Based on the DRS and SPS results,the mechanism about the photogenerated carrier transfer between TiO2 and ZnPc is proposed.At a lower ZnPc content(≤0.20 μmol/g),ZnPc monomer acts as the electron donor,which provides the photoinduced electrons to the conduction band of TiO2.These photoinduced electrons can transfer to molecular oxygen(O2),leading to the formation of active species,such as superoxide/hydroxide radicals and singlet oxygen,which is beneficial to the photocatalytic reaction.While at a higher ZnPc content(>0.20 μmol/g),the formation of ZnPc dimer results in the decrease of photocatalytic activities of ZnPc-TiO2 photocatalyst.
基金Projects(50502013, 562869) supported by the National Natural Science Foundation of ChinaProject(2005AFQXJ062) supported by Harbin Youth Foundation, ChinaProject(20070410892) supported by China Postdoctoral Science Foundation
文摘Novel linear and star branched triphenylamine-containing aromatic imides were designed and synthesized by the condensation between amine-substituted triphenylamine and naphthalene-1, 4, 5, 8-tetra-carboxylic dianhydride in order to investigate the influence of topological structure on the photophysical performance. The polyimides were characterized by elementary analysis and FTIR measurements. Thermogravimetric analysis (TGA) shows that the onset temperatures of decomposition (Td) for 5% mass loss range from 371 to 445 ℃. UV-Vis spectrum, quantum chemical calculation and cyclic voltammetry (CV) were used to obtain the dependence of energy levels on the function of structures. The introduction of triphenylamine group changes the energy level of the entire dye system. The dye-sensitized solar cells (DSSCs) prepared by using the dyes have a strong photoelectric current response in visible light region of 400-600 nm.
基金supported by the National Natural Science Foundation of China(21271004,51372003,21271003,21275006)the Natural Science Foundation of Anhui Province(1208085MB22,1308085MB24)+2 种基金Ministry of Education Funded Projects Focus on returned overseas scholar,Department of Education of Anhui Province(KJ2012A025)Program for New Century Excellent Talents in University(China)Doctoral Program Foundation of Ministry of Education of China(20113401110004)
文摘A novel pyrazole derivative ligand, BTA(BTA = bis-(4-ethoxy-phenyl)-[4-(tripyrazol-1-yl-methyl)-phenyl]-amine), was synthesized and fully characterized by 1H-NMR, MALDI-TOF-MS spectra and single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1, with a = 11.827(1), b = 16.000(2), c = 16.527(2)A, α = 108.510(1), β = 91.116(5), γ = 101.734(1)°, V = 2894.5(6) A3, Z = 1, Dc = 1.262 g/m^3, F(000) = 1162, Μr = 545.63, μ = 0.083 mm-1, the final R = 0.0728 and w R = 0.2213 for 7541 observed reflections with I 〉 2(I). The structural analysis revealed that three pyrazole units are attached to the same carbon atom connected with bis-(4-ethoxy-phenyl)-phenyl-amine group. UV-vis spectral features of the ligand in various solutions were explained by time dependent density functional theory(TD-DFT). It was also found that the ligand(BTA) exhibits an exclusively selective and sensitive response toward Fe3+ using UV-vis spectroscopic method.
基金Supported by the National Natural Science Foundation of China(No.20676027)Postdoctoral Foundation of Heilongjiang Province,China(No.LBH-Q07111)
文摘Fe(Ⅱ) was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%---4% HF to remove the SiO2 template and then calcined. It was found that nanowire bundles, dendritic plates of porous iron oxide, dense parallel backbones of porous iron oxide were obtained at -1.4-- -1.6 V and 0.08--0.1 mol/L electrolyte concentration after calcinations; the dendritic pattern of porous iron oxide film templated by the SBA-16 film was obtained in macrostructure at a higher absolute value of cathode potential(-1.7-- -1.8 V) and a lower electrolyte concentration(0.02-0.05 mol/L), the dendritic pattern of porous iron oxide film could copy the microstructure of SBA-16 film; Fe(II) nanowires grew and formed in one dimension(1D) and two-dimension(2D) electrocrystallization at a potential of-l.6-- -1.7 V and an electrolyte concentration of 0.05 mol/L, and the shape of the ID or 2D crystalline iron oxide nanowires calcined was similar to the original shape of the SBA-16 channels. The desired morphology and size of porous nanocrystal iron oxide can be obtained by adjusting the applied potential value and electrolyte concentration, and all kinds of morphologies of porous nanostructure crystal iron oxide can be prepared.
基金financially supported by the National Natural Science Foundation of China(nos.21773060,51774002,and 21601054)Fundamental Research Funds for the Central Universities(no.N182304014)+1 种基金Youth Innovation Team Project of Science and technology of Heilongjiang University(2018-KYYWF-1593)Young Scholar Project of the Long Jiang Scholars Program(Q201818)
文摘SrLi_(2)Ti_(6)O_(14)(SLTO)coated with different amount of ZrO_(2)was successfully prepared.The as-obtained composites are stacked by a series of particles with a pure phase structure and a good crystallinity.Furthermore,ZrO_(2)coating not only enhances the structural stability of the materials but also facilitates the diffusion of lithium through the SEI film.As a result,the redox polarization was reduced,and the reversibility of the electrochemical reaction was enhanced.Particularly,SLTO-ZrO_(2)-2 sample delivers a high initial lithiation capacity of 283.6 mA h g^(-1),and the values maintain at 251.7,228.0,207.4,175.3,and 147.7 mA h g^(-1)at the current densities of 0.13,0.26,0.54,1.31,and 2.62 A g^(-1),respectively.Our experiment also confirmed that SLTO materials coated with ZrO_(2)are suitable for high power density applications,and the lithiation specific energy efficiency of SLTO-ZrO_(2)-2 is 200%as high as that of pure SLTO at a power density of 1257 W kg^(-1).
基金Funded by the National Natural Science Foundation of China (Nos.31000773 and 31072119)Key Scientific and Technological Planning Project of Harbin (No.2009AA6CN125)Innovation Foundation of Harbin (No.2010RFQXN091)
文摘To optimize the preparation process of chitosan microspheres and study its loading capacity, chitosan microsphere was prepared by crosslinking with glutaraldehyde, and bovine serum albumin (BSA) was absorbed onto chitosan microsphere. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FITR), TA instruments and zeta potentiometer analyzer were used to characterize the parameters with respect to size, thermal characters, morphology, and zeta potential of the microspheres. The loading capability and in vitro release tests were carried out. The results showed that chitosan microsphere with particle size less than 10 μm and positively charged (+25.97±0.56 mV) can be obtained under the aldehyde group to amino group ratio at 1:1. A loading capacity of BSA at 28.63±0.15 g/100 g with corresponding loading efficiency at 72.01±1.44% was obtained for chitosan microsphere. In vitro test revealed a burst release followed by sustained-release profile.