一氯氧化物及其负离子的分子结构和热力学性质

利用两种杂化DFT方法(BHLYP和B3LYP,两种纯DFT方法(BP86和BLYP),以DZP++为基函数对ClOO,ClOOO和ClO3及其负离子的平衡构型进行了量子化学计算,研究了它们的几何构型、相对能量、三种电子亲和势(绝热电子亲和势Ead=E(optimizedneutral)-E(optimizedanion),垂直电子亲和势Evert=E(optimizedneutral)-E(anionatneutralequilibriumgeometry)和垂直电子解离能Evd=E(neutralatanionequilibrium)-E(optiminzedanion))和红外振动频率.

Effect of Inhibitor K-23 on O_2-evolution and Hill Activity of PSⅡ Membrane Fragments of Spinacia oleracea

研究了新的抑制剂K_2 3对波菜 (SpinaciaoleraceaMill.)PSⅡ放氧活性和 2 ,6_dichlorophenolindophenol (DCIP)光还原活性的影响。研究发现 :抑制剂K_2 3在低浓度时对PSⅡ放氧活性有明显促进作用 ,而对DCIP光还原活性的促进作用不太明显。在高浓度时抑制PSⅡ放氧活性和DCIP光还原。对K_2 3的抑制部位进行了初步探讨。

Recent progress in production and usage of hydrogen peroxide

Hydrogen peroxide has attracted increasing interest as an environmentally benign and green oxidant that can also be used as a solar fuel in fuel cells.This review focuses on recent progress in production of hydrogen peroxide by solar-light-driven oxidation of water by dioxygen and its usage as a green oxidant and fuel.The photocatalytic production of hydrogen peroxide is made possible by combining the e^(-)and 4e-oxidation of water with the e^(-)reduction of dioxygen using solar energy.The catalytic control of the selectivity of the e^(-)vs.4e-oxidation of water is discussed together with the selectivity of the e^(-)vs.4e-reduction of dioxygen.The combination of the photocatalytic e^(-)oxidation of water and the e^(-)reduction of dioxygen provides the best efficiency because both processes afford hydrogen peroxide.The solar-light-driven hydrogen peroxide production by oxidation of water and by reduction of dioxygen is combined with the catalytic oxidation of substrates with hydrogen peroxides,in which dioxygen is used as the greenest oxidant.

Role of transition-metal electrocatalysts for oxygen evolution with Si-based photoanodes

A comprehensive understanding of the role of the electrocatalyst in photoelectrochemical(PEC)water splitting is central to improving its performance.Herein,taking the Si-based photoanodes(n^(+)p-Si/SiO_(x)/Fe/FeOx/MOOH,M=Fe,Co,Ni)as a model system,we investigate the effect of the transition-metal electrocatalysts on the oxygen evolution reaction(OER).Among the photoanodes with the three different electrocatalysts,the best OER activity,with a low-onset potential of∼1.01 VRHE,a high photocurrent density of 24.10 mA cm^(-2)at 1.23 VRHE,and a remarkable saturation photocurrent density of 38.82 mA cm^(-2),was obtained with the NiOOH overlayer under AM 1.5G simulated sunlight(100 mW cm^(-2))in 1 M KOH electrolyte.The optimal interfacial engineering for electrocatalysts plays a key role for achieving high performance because it promotes interfacial charge transport,provides a larger number of surface active sites,and results in higher OER activity,compared to other electrocatalysts.This study provides insights into how electrocatalysts function in water-splitting devices to guide future studies of solar energy conversion.

A tetragonal tungsten bronze-type photocatalyst:Ferro-paraelectric phase transition and photocatalysis

Although ferroelectrics have potential applications in photocatalysis due to their highly efficient charge separation, their mechanism of charge separation is still unknown. A ferroelectric Sr0.7Ba0.3Nb2O6 （SBN‐70） semiconductor with a low ferro‐paraelectric phase transition （65℃） was studied. The photocatalytic activity for H2 production by ferroelectric and paraelectric SBN‐70 was examined. The spontaneous polarization in the ferroelectric phase strongly affected the photocata‐lytic performance and parallel ferroelectric domains significantly promoted photogenerated charge separation to result in better photocatalytic H2 production. This knowledge provides an important basis for the fabrication of ferroelectric photocatalysts with improved charge separation ability.

Synergistic integration of metallic Bi and defects on BiOI: Enhanced photocatalytic NO removal and conversion pathway

Surface plasmon resonance(SPR)of metals may provide a way to improve light absorption and utilization of semiconductors,achieving better solar light conversion and photocatalysis efficiency.This study uses the advantages of SPR in metallic Bi and artificial defects to cooperatively enhance the photocatalytic performance of BiOI.The catalysts were prepared by partial reduction of BiOI to form Bi@defective BiOI,which showed highly enhanced visible photocatalytic activity for NOx removal.The effects of reductant quantity on the photocatalytic performance of Bi@defective BiOI were investigated.The as-prepared photocatalyst(Bi/BiOI-2)using 2 mmol of reductant NaBH4 showed the most efficient visible light photocatalytic activity.This enhanced activity can be ascribed to the synergistic effects of metallic Bi and oxygen vacancies.The electrons from the valence band tend to accumulate at vacancy states;therefore,the increased charge density would cause the adsorbed oxygen to transform more easily into superoxide radicals and,further,into hydroxyl radicals.These radicals are the main active species that oxidize NO into final products.The SPR effect of elemental Bi enables the improvement of visible light absorption efficiency and the promotion of charge carrier separation,which are crucial factors in boosting photocatalysis.NO adsorption and reaction processes on Bi/BiOI-2 were dynamically monitored by in situ infrared spectroscopy(FT-IR).The Bi/BiOI photocatalysis mechanism co-mediated by elemental Bi and oxygen vacancies was proposed based on the analysis of intermediate products and DFT calculations.This present work could provide new insights into the design of high-performance photocatalysts and understanding of the photocatalysis reaction mechanism for air-purification applications.

The pivotal effects of oxygen vacancy on Bi_2MoO_6:Promoted visible light photocatalytic activity and reaction mechanism

Bi2MoO6,a typical Bi-based photocatalyst,has received increasing interests and been widely applied in various fields.However,the visible light photocatalytic activity of Bi2MoO6 is still restricted by some obstacles,such as limited photo-response and low charge separation efficiency.In this work,we developed a facile method to introduce artificial oxygen vacancy into Bi2MoO6 microspheres,which could effectively address these problems and realize highly efficient visible light photocatalysis.The experimental and theoretical methods were combined to explore the effects of oxygen vacancy on the electronic structure,photocatalytic activity and the reaction mechanism toward NO removal.The results showed that the addition of NaBH4 during catalyst preparation induced the formation of oxygen vacancy in Bi2MoO6,which plays a significant role in extending the visible light absorption of Bi2MoO6.The visible light photocatalytic activity of Bi2MoO6 with oxygen vacancy was obviously enhanced with a NO removal ratio of 43.5%,in contrast to that of 25.0%with the pristine Bi2MoO6.This can be attributed to the oxygen vacancy that creates a defect energy level in the band gap of Bi2MoO6,thus facilitating the charge separation and transfer processes.Hence,more reactive radicals were generated and participated in the photocatalytic NO oxidation reaction.The in situ FT-IR was used to dynamically monitor the photocatalytic NO oxidation process.The reaction intermediates were observed and the adsorption-reaction mechanism was proposed.It was found that the reaction mechanism was unchanged by introducing the oxygen vacancy in Bi2MoO6.This work could provide new insights into the understanding of the oxygen vacancy in photocatalysis and gas-phase photocatalytic reaction mechanism.

Effect of calcination temperatures on photocatalytic H_(2)O_(2)-production activity of ZnO nanorods

Photocatalytic hydrogen peroxide(H_(2)O_(2))production from O_(2) and H2O is an ideal process for solar‐to‐chemical energy conversion.Herein,ZnO nanorods are prepared via a simple hydrothermal method for photocatalytic H_(2)O_(2) production.The ZnO nanorods exhibit varied performance with different calcination temperatures.Benefiting from calcination,the separation efficiency of photo‐induced carriers is significantly improved,leading to the superior photocatalytic activity for H_(2)O_(2) production.The H_(2)O_(2) produced by ZnO calcined at 300℃ is 285μmol L^(−1),which is over 5 times larger than that produced by untreated ZnO.This work provides an insight into photocatalytic H2O2 production mechanism by ZnO nanorods,and presents a promising strategy to H2O2 production.

Synthesis,characterization and application of BiVO_4 photoanode for photoelectrochemical oxidation of chlorate

A high‐quality polycrystalline bismuth vanadate(BiVO4)film was prepared on a fluorine‐doped tinoxide substrate via a facile two‐step strategy involving electrodeposition and annealing processes.The morphology and structural characterization of the resulting film were investigated by differentmethods including scanning electron microscopy,transmission electron microscopy,X‐ray diffraction(XRD),and Fourier transform infrared,ultraviolet‐visible(UV‐vis)absorption,and Ramanspectroscopies.XRD patterns as well as optical measurements revealed that BiVO4film crystallizedwith a pure monoclinic scheelite structure.The prepared BiVO4film was used for heterogeneousoxidation of chlorate ions in aqueous solution via electrochemical(EC),photochemical(PC),andphotoelectrochemical(PEC)processes.The decrease in concentration of chlorate was monitoredusing UV‐vis absorption spectroscopy.The results revealed that BiVO4could effectively performchlorate oxidation under light irradiation through a PEC method.The kinetics of chlorate oxidationwas consistent with a first‐order reaction,and the rate constant for the PEC process was found to bemuch higher than those of EC and PC.Furthermore,a possible photocatalytic oxidation mechanismfor chlorate mainly based on the formation of perchlorate ions is proposed.

In situ formation of amorphous Fe-based bimetallic hydroxides from metal-organic frameworks as efficient oxygen evolution catalysts

Oxygen evolution from water driven by electrocatalysis or photocatalysis poses a significant challenge as it requires the use of efficient electro-/photo-catalysts to drive the four-electron oxygen evolution reaction(OER).Herein,we report the development of an effective strategy for the in situ chemical transformation of Fe-based bimetallic MIL-88 metal-organic frameworks(MOFs)into corresponding bimetallic hydroxides,which are composed of amorphous ultrasmall nanoparticles and afford an abundance of catalytically active sites.Optimized MOF-derived NiFe-OH-0.75 catalyst coated on glassy carbon electrodes achieved a current density of 10 mA cm^(-2)in the electrocatalytic OER with a small overpotential of 270 mV,which could be decreased to 235 mV when loading the catalysts on a nickel foam substrate.Moreover,these MOF-derived Fe-based bimetallic hydroxides can be used as efficient cocatalysts when combined with suitable photosensitizers for photocatalytic water oxidation.

Preparation of Cu-BiVO_4 and Its Photocatalytic Properties for Desulfurization of Model Oil

A photocatalyst Cu-BiVO4 was synthesized by the hydrothermal method and was characterized by XRD, UV-vis DRS, and N2 adsorption-desorption measurement. The catalytic activity of the Cu-BiVO4 samples was studied on desulfurization of thiophene dissolved in n-octane, which was used as a model light oil, via photocatalytic oxidation reaction under illumination by visible light. The catalyst characterization results indicated that the loading of Cu on the catalyst did not change the crystal phase of BiVO4, and the crystallinity of the Cu-BiVO4 sample was found to be better at pH=7. The Cu-BiVO4 samples presented a significant bathochromic shift of the absorption band in the visible region, and the absorption intensity increased for the composite catalyst. The desulfurization experiments showed that the Cu-BiVO4 sample prepared at a pH value of 7 had a better catalytic activity. Under proper operating conditions, the desulfurization rate of the model compound achieved by Cu-BiVO4 sample prepared at pH=7 could reach as high as 90%.

Pivotal roles of artificial oxygen vacancies in enhancing photocatalytic activity and selectivity on Bi_2O_2CO_3 nanosheets

There is an increasing interest in bismuth carbonate(Bi2O2CO3,BOC)as a semiconductor photocatalyst.However,pure BOC strongly absorbs ultraviolet light,which drives a high recombination rate of charge carriers and thereby limits the overall photocatalysis efficiency.In this work,artificial oxygen vacancies(OV)were introduced into BOC(OV-BOC)to broaden the optical absorption range,increase the charge separation efficiency,and activate the reactants.The photocatalytic removal ratio of NO was increased significantly from 10.0%for pure BOC to 50.2%for OV-BOC because of the multiple roles played by the oxygen vacancies.These results imply that oxygen vacancies can facilitate the electron exchange between intermediates and the surface oxygen vacancies in OV-BOC,making them more easily destroyed by active radicals.In situ DRIFTS spectra in combination with electron spin resonance spectra and density functional theory calculations enabled unraveling of the conversion pathway for the photocatalytic NO oxidation on OV-BOC.It was found that oxygen vacancies could increase the production of active radicals and promote the transformation of NO into target products instead of toxic byproducts(NO2),thus the selectivity is significantly enhanced.This work provides a new strategy for enhancing photocatalytic activity and selectivity.

A Novel Multi-Tube Photoreactor with UV Light and Immobilized TiO_2 Thin Film for Water Treatment

A novel multi-tube photoreactor with 0.0188m3 valid reaction volume was constructed in pilot-scale. This rectangular reactor consisted of 13 regularly distributed silica glass tubes coating with TiO2 thin film photo-catalyst. Total active area of TiO2 thin film is 0.3916m2. The ratio of surface area to volume achieves 20.8m-1. Photocatalytic experiment of phenol red demonstrates that the apparent reaction rate constant (k) is 0.074 65 h-1 and 0.16502h-1 for reaction system with and without micro-bubbles mixing. The corresponding apparent quantum efficiency (a) is 8.1771 X 10-7g.J-1 and 4.9036 x 10-7g-J-1, respectively. COD value of reactant could decrease to 17mg.L-1 and high performance liquid chromatography (HPLC) only shows two absorption peaks in 24 h pho-tocatalytic process time, so this photoreactor has good photomineralization effect. Experimental results reveal that photocatalytic destruction of organics is possible by using the multi-tube photoreactor.

Blocking backward reaction on hydrogen evolution cocatalyst in a photosystem Ⅱ hybrid Z-scheme water splitting system

Photocatalytic Z-scheme water splitting is considered as a promising approach to produce solar hydrogen.However,the forward hydrogen production reaction is often impeded by backward reactions.In the present study,in a photosystem Ⅱ-integrated hybrid Z-scheme water splitting system,the backward hydrogen oxidation reaction was significantly suppressed by loading a PtCrOx cocatalyst on a ZrO2/TaON photocatalyst.Due to the weak chemisorption and activation of molecular hydrogen on PtCrOx,where Pt is stabilized in the oxidized forms,Pt^Ⅱ and Pt^Ⅳ,hydrogen oxidation is inhibited.However,it is remarkably well-catalyzed by the metallic Pt cocatalyst,thereby rapidly consuming the produced hydrogen.This work describes an approach to inhibit the backward reaction in the photosystem Ⅱ-integrated hybrid Z-scheme water splitting system using Fe(CN)6^3-/Fe(CN)6^4-redox couple as an electron shuttle.

Revealing the unexpected promotion effect of EuO_x on Pt/CeO_2 catalysts for catalytic combustion of toluene

Pt/Eu2O3-CeO2 materials with different Eu concentrations were prepared and applied to toluene destruction,and the remarkable promotion impact of EuOx on Pt/CeO2 can be observed.The characterization results reveal that the presence of EuOx significantly enhances the redox property,lattice O concentration,and Ce3+ ratio of the Pt/CeO2 material,which facilitates the dispersion and activity of Pt active sites and thus accelerates the decomposition process of toluene.Among all catalysts,a sample with an Eu content of 2.5 at.%(Pt/EC-2.5)possesses the best catalytic activity with 0.09 vol% of toluene completely destructed at 200 ℃ under a relatively high GHSV of 50000 h^-1.The possible reaction pathway and mechanism of toluene combustion over Pt/Eu2O3-CeO2 samples are presented according to in-situ DRIFTS,which confirms that the toluene oxidation process obeys the Mars-van Krevelen mechanism with aldehydes and ketones as primary organic intermediates.

Influence of Dispersion of Nano-ZnO Particles in Polymer Matrices on Properties of Relevant Nano Composite Fibers

The surface-passivated and non-surface-passivated zinc oxide nano-particles （marked as s-nanoZnO and ns-nanoZnO respectively） were evenly dispersed in polymer solutions with the aid of ultrasonic vibration to prepare nanocomposite film by free casting and to prepare nanocomposite fibers by wet spinning and to prepare nancomposites coating by surface smearing. The dispersion of s-nanoZnO and nsnanoZnO in PAN matrix were observed by transmittance electron microscopy, the mechanical properties of the relevant compesite samples were studied by INSRTON tensile strength tester. It was found that s-nanoZnO behaves a well-dispersed morphology in PAN films and fibers when its concentration was 2 wt% but ns-nanoZnO nano particles agglomerate into larger congeries in PAN films. It means that the surface-passivated process oft zinc oxide nano. particles was effective to disperse. The relative intensity and elonsation at break of s-nanoZnO-PAN composite fibers show maximum values with the increase of nano particle content in compesites （from 0 wt% to 2 wt% of s- nanoZnO）. The elasticity of the composite fibers increases whereas their modulus declines. Balanced the changes of the properties mentioned above, 2 wt% s-nanoZnO in PAN matrix is a proper content for the composite fibers spun by wet spinning. The result of surface smearing test means that the reactim between s-nanoZnO and polymer can be indicated by the color of nanocomposite surface coat on fibers.

Kinetics of Oxidation of Lactose with Photochemically Generated Radicals

Lactose milk sugar is found only in the milk of mammals. In order to understand the mechanism of oxidation of lactose, a systematic kinetic study of oxidation of lactose with photochemicaUy generated radicals was carried out. The reaction has a first order dependence on chloramine-T as well as on substrate. The reaction is catalysed by H＋ ions as well. On the basis of kinetic results and product analysis a probable mechanism were suggested.

Ordered mesoporous carbon supported bifunctional PtM(M=Ru,Fe,Mo)electrocatalysts for a fuel cell anode

The deposition onto an ordered mesoporous carbon（OMC）support of well dispersed PtM（M = Ru,Fe,Mo）alloy nanoparticles（NPs）were synthesized by a direct replication method using SBA-15 as the hard template,furfuryl alcohol and trimethylbeneze as the primary carbon sources,and metal acetylacetonate as the alloying metal precursor and secondary carbon source.The physicochemical properties of the PtM-OMC catalysts were characterized by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray absorption near edge structure,and extended X-ray absorption fine structure.The alloy PtM NPs have an average size of 2-3 nm and were well dispersed in the pore channels of the OMC support.The second metal（M）in the PtM NPs was mostly in the reduced state,and formed a typical core（Pt）-shell（M）structure.Cyclic voltammetry measurements showed that these PtM-OMC electrodes had excellent electrocatalytic activities and tolerance to CO poisoning during the methanol oxidation reaction,which surpassed those of typical activated carbon-supported PtRu catalysts.In particular,the PtFe-OMC catalyst,which exhibited the best performance,can be a practical anodic electrocatalyst in direct methanol fuel cells due to its superior stability,excellent CO tolerance,and low production cost.

Synthesis, characterization and electrochemical recognition of metal ions of three new ferrocenyl derivatives containing pyridyl moiety

Three new ferrocene （Fc） based receptors with pyridyl moiety, named methyl-6- ferrocenoylacetyl-2-pyridine carboxylate （FcLl）, 1,1＇-（2,6-bispyridyl）bis-3-ferrocenyl-l,3-propanedione （FcL2）, ferrocenecarboxaldehyde-2,6-dipicolinoyhydrazone （FcL3） were synthesized, and further characterized by elemental analysis, IR spectra, UV-Vis spectra, 1H and 13C NMR. The electrochemical properties and ion sensing properties of FcL1, FcL2 and FcL3 were also investigated by means of cyclic voltammetry in ethanol solution with 0.1 mol/L LiC104 as the supporting electrolyte. The E~ values of the receptors increase with the scanning rate increasing at high scanning rate, and Ipa/Ipo approaches unity, indicating that the redox reaction is basically reversible. Their recognition performances to different metal cations such as Cd（II）, Co（II）, Cu（II）, Hg（II）, Mn（II）, Ni（II）, Zn（II） show that the FcL1 is responsive to Cu（II） with the maximum electrochemical shift of the FcL1 for Cu（II）of about 72.0 mV, whereas the FcL2 is responsive to Cu（II） and Mn（II） with shift of 102 mV and 109 mV, respectively, and the FcL3 is responsive to Hg（II） and Mn（II） with the shift of 53.0 mV and 54.0 mV, respectively. All the results show that these receptors may have potential applications in electrochemical sensor technology, material science, and molecular devices.

Studies of Photocatalytic Kinetics on the Degradation of Bisphenol A （BPA） by Immobilized ZnO Nanoparticles in Aerated Photoreactors

The photocatalytic kinetics of BPA （4, 4＇-isopropylidenediphenol）, a representative endocrine disruptor, was explored using immobilized ZnO nanoparticles as a photocatalyst in a laboratory scale photocatalytic reactor. The conditions of photocatalytic degradation were optimized. Direct photocatalytic degradation of BPA was undertaken in an aqueous solution containing ZnO nanoparticles under the optimized experimental conditions. The effects of various factors, such as initial BPA concentrations, initial pH values and various anions （CI, NO3, COa2, SO42-, HCO3＂） were investigated. In the case of the nanoparticles derived films, the photocatalytic efficiency was found not to be remarkably related with the calcination temperature employed in the coating process. Screen-printed ZnO nanoparticles films obtained in the optimal processing conditions showed that the photocatalytic activity is comparable to ZnO nanoparticles in aqueous suspensions. Over 90% degradation efficiency of BPA was achieved under the optimum conditions. The degradation rates in all photocatalytic experiments were linear with the degradation efficiencies of BPA by regression analysis （r ≥ 0.99）. The results showed that the degradation kinetics of BPA in the reactor with immobilized nano-ZnO film as photocatalyst was in agreement with a pseudo-first order rate law.