A metal-organic framework/inorganic composite(ZIF-8@AMP)was synthesized by the in situ introduction of the active component ammonium phosphomolybdate(AMP)during the ambient solution-phase synthesis of the metal-organi...A metal-organic framework/inorganic composite(ZIF-8@AMP)was synthesized by the in situ introduction of the active component ammonium phosphomolybdate(AMP)during the ambient solution-phase synthesis of the metal-organic framework(ZIF-8).The structure and properties of the composite were characterized using scanning electron microscopy(SEM),X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TGA),and Fourier transform infrared spectroscopy(FTIR).Its adsorption performance for Rb^(+)and Cs^(+)in water was investigated.Results indicate that ZIF-8@AMP exhibited adsorption efficiencies of 93.5%and 95.6%for Rb^(+)and Cs^(+)within 30 min,with maximum adsorption capacities of 92.7 and 104.5 mg·g^(-1),respectively.After five adsorption-desorption cycles,it maintained high adsorption capacity and achieved over 84.9%adsorption efficiency for Rb^(+)and Cs^(+)in actual brine samples.The adsorption of ZIF-8@AMP for Rb^(+)and Cs^(+)follows pseudosecond-order kinetics and the Langmuir adsorption isotherm,indicating an endothermic,entropy-increasing,and spontaneous process.The adsorption mechanism involves electrostatic attraction and ion exchange between ZIF-8@AMP and Rb^(+)and Cs^(+).展开更多
Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed...Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.展开更多
Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature...Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by BET method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9℃/min. FePMo12 was found to be a more active catalyst for propene （17.2% yield） with minimal over deep oxidation （0.3% yield in COx）.展开更多
Abstra ct Utilizing efficient and durable photocatalysts for the removal of carcinogen Cr(Ⅵ)in wide pH water environment is of great significance for environment remediation.Herein,three conjugated organic component-...Abstra ct Utilizing efficient and durable photocatalysts for the removal of carcinogen Cr(Ⅵ)in wide pH water environment is of great significance for environment remediation.Herein,three conjugated organic component-functionalized hourglass-type phosphomolybdate hybrids with the formulas(H_(2)DBQ)[Fe(-H_(2)O)_(3)]_(2){Fe[P_(4)Mo_(6)0_(31)H_(7)]_(2)}·7H_(2)O(1),(H_(2)DBQ)_(2)(H_(2)DBP)[Fe(H_(2)O)_(4)]{Fe[P_(4)Mo_(6)O_(31)H_(7)]_(2)}·4H_(2)O(2),(H_(2)DBP)_(2){Fe[P_(4-)Mo_(6)O_(31)H_(9)]_(2)}·10H_(2)O(3)(DBQ=2,2'-dimehyl-6,6'-biquinoline;DBP=4,4'-diaminobiphenyl)were synthesized via hydrothermal method as photocatalysts for reducing Cr(Ⅵ)under visible light illumination.Structure analysis showed that hybrids 1-3 consist of hourglass-type[Fe(P_(4)Mo_(6)O_(31)H_(6))_(2)]^(10)-(abbr.Fe{P_(4)Mo_(6)}_(2))poly anionic clusters functionalized with different proportional of conjugated organic components(DBQ and DBP)effectively regulated their visible-light absorption capabilities and electron structures,which could be employed to reflect the structure-activity relationship of materials.When used as catalysts for reducing Cr(Ⅵ),hybrids 1-3 displayed distinct photocatalytic activities with Cr(Ⅵ)removal efficiencies of 91%,86%and 81%with only 10 W of white light being used as illumination,which are superior to that of pristine Fe{P_(4)Mo_(6)}_(2)salt(62%).Moreover,hybrid 1 also maintained high Cr(Ⅵ)removal efficiencies above~85%and high structural stabilities in solutions with wide pH ranges of2.5-10.0.Mechanism investigation showed that the higher organic component conjugation levels could promote the optic al absorption and facilitate the electron transfer between Fe{P_(4)Mo_(6)}_(2)and org anic components,thus resulting in effective Cr(Ⅵ)reduction photocatalytic efficacy.This work provides a viable way to design the photocatalysts based on polyoxometalates for removing wastewater pollutants.展开更多
Photo-assisted electrochemical technique provides a promising approach towards carcinogen chromium(Ⅵ)detection,which requires reasonable catalyst design.Herein,an unusual hexa-nuclear cadmium cluster functionalized r...Photo-assisted electrochemical technique provides a promising approach towards carcinogen chromium(Ⅵ)detection,which requires reasonable catalyst design.Herein,an unusual hexa-nuclear cadmium cluster functionalized reductive phosphomolybdate hybrid as photo-electrochemical sensor was designed and synthesized with formula of{[Cd(H_(2)O)_(2)]_(2)[Cd(btmbp)]_(2)}{Cd(P_(4)Mo_(6)O_(31)H_(7))_(2)}·20H_(2)O(1)(btmbp=4,4′-bis((^(1)H-1,2,4-triazol-1-yl)methyl)biphenyl),in which the photoactive hexa-nuclear{Cd_(6)}clusters cooperated with reductive phosphomolybdate[P_(4)Mo_(6)O_(31)]^(12)−endow the material with wide light absorption and remarkable redox activity,thus achieving efficient photo-assisted electrochemical Cr(Ⅵ)detection performance.Under visible-light assistance,the detection limit(LOD)and sensitivity of Cr(Ⅵ)is 4.17 nmol/L(0.225 ppb)and 226.32μA L/μmol,which is apparently superior to the performance without photo-assistance(6.25 nmol/L and 106.95μA L/μmol)and far satisfies the demands of world health organization(WHO)for potable water(50 ppb).Moreover,compound 1 showed prominent Cr(Ⅵ)detection performance in practical water samples together with remarkable anti-interference capacity and good electrochemical durability.This work provides an important guidance for designing efficient polyoxometalate-based crystalline sensors for Cr(Ⅵ)detection.展开更多
A novel compound [H-IDP]4[PMo12O40]·8H2O 1 based on Keggin-type phosphor- molybdate has been synthesized by hydrothermal method and characterized by IR spectroscopy, elemental analyses and single-crystal X-ray di...A novel compound [H-IDP]4[PMo12O40]·8H2O 1 based on Keggin-type phosphor- molybdate has been synthesized by hydrothermal method and characterized by IR spectroscopy, elemental analyses and single-crystal X-ray diffraction. The composite crystallizes in the mono- clinic system, space group C2/m with a = 13.937（5）, b = 27.033（5）, c = 10.857（5） A, β = 122.489（5）°, V = 3450（2）A^3, Mr = 2611.11, Z = 2, Dc = 2.498 g/cm^3, F（000） = 2486,μ = 2.243 mm^-1, the final R = 0.0568 and wR = 0.1216 for 2707 observed reflections with I 〉 2σ（I）. X-ray structural study shows that 1 consists of a [PMo12O40]^4- polyanion, four protonated IDP cations and eight H2O molecules. In the structure of 1, a 3D network forms by hydrogen bond of [PMo12O40]^4- polyanion, HIDP^＋ cation and H2O molecules. Upon excitation wavelength of 280 nrn in hydroxylic solvents at room temperature, 1 shows fluorescence property.展开更多
Phospbomolybdate （PMo） with varying Mo loadings ranging from 5-30 wt% on alumina were prepared by incipient wetness impregnation method. 0.5 wt% of Pt was further loaded in order to prepare the bifunctional （metal-...Phospbomolybdate （PMo） with varying Mo loadings ranging from 5-30 wt% on alumina were prepared by incipient wetness impregnation method. 0.5 wt% of Pt was further loaded in order to prepare the bifunctional （metal-acid） Pt-PMo/Al2O3 catalysts. Thus prepared catalysts showed very high catalytic activities for n-heptane hydroisomerization compared with Pt impregnated MoO3 catalysts supported either on Al2O3 or on AIPO4. The conversion of n-heptane increased with Mo loading up to 20 wt% and slightly decreased with further Mo loading. However, the selectivity towards isomers showed an increasing trend up to 30 wt% of Mo in the catalyst. A relationship between catalytic activity and acidic strength was established in the present study.展开更多
Transition-metal substituted Keggin-type polyoxometalates(POMs)are of great interest for applications in biomedicine,material science,and catalysis.The synthesis of transition metal-substituted Keggin-type polytungsta...Transition-metal substituted Keggin-type polyoxometalates(POMs)are of great interest for applications in biomedicine,material science,and catalysis.The synthesis of transition metal-substituted Keggin-type polytungstates via the formation of a lacunary structure is well established,in contrast this approach is so far unexplored for Keggin-type polymolybdates.This is because the prevailing doctrine assumes that the lacunary Keggin phosphomolybdate[PMo_(9)O_(34)]^(9−)is too unstable and can only be stabilized with organic ligands such as pyridine in organic solvents.In this work,we present a reliable procedure for the synthesis of the lacunary compound[PMo_(9)O_(34)]^(9−)and its application in a novel in situ approach for the synthesis of different metal substituted POMs.The method is based on generating the lacunary species in situ,where the metal-substituted POMs are produced by adding another precursor compound.We employed this method to synthesize several new specific element-substituted POMs,which we present with comprehensive characterization.The interpretation of the analytical results was complemented by DFT calculations.For the separation of by-products from synthesis,we employed a novel membrane-based nanofiltration process,that enables superior separation of alkali salts from the POM solution resulting in>99%rejection of the POM components.展开更多
With hydrogen bond-directed three-dimensional phosphomolybdate-based supramolecular architecture as a precursor,a Mo_(2)C composite material(Mo_(2)C@NC)supported by nitrogen-doped carbon matrix was fabricated successf...With hydrogen bond-directed three-dimensional phosphomolybdate-based supramolecular architecture as a precursor,a Mo_(2)C composite material(Mo_(2)C@NC)supported by nitrogen-doped carbon matrix was fabricated successfully through calcination.In this composite material,Mo_(2)C particles with size about 5 to 8 nm disperse evenly in the framework of nitrogen-doped mesoporous carbon matrix.In acid media,to achieve a current density of 10 mA cm^(-2),the overpotential required was 142 mV with a Tafel slope of 63 mV dec−1.Under basic conditions,the overpotential reduced to as low as 56 mV with a Tafel slope of 59 mV dec−1.To realize overall water splitting,MoO_(2)-based composite material(MoO_(2)@NC)with nitrogen-doped carbon as matrix was obtained using the same precursor as Mo_(2)C@NC.MoO_(2)@NC exhibits excellent oxygen evolution reaction(OER)performance with an over potential of 302 mV.With Mo_(2)C@NC as cathode and MoO_(2)@NC as anode,an efficient electrolyzer was constructed,which required a cell voltage of 1.60 V to achieve a current of 10 mA cm^(-2) in 1.0 M KOH.Furthermore,besides overall water splitting,Mo_(2)C@NC also shows striking catalytic removal property towards 4-nitrophenol and Rhodamine B.展开更多
Oxidative catalysis enables lignin depolymerization to yield carbonyl-containing aromatic chemicals for sustainable lignocellulose valorization.The oxidative depolymerization of lignin requires high oxygen pressure an...Oxidative catalysis enables lignin depolymerization to yield carbonyl-containing aromatic chemicals for sustainable lignocellulose valorization.The oxidative depolymerization of lignin requires high oxygen pressure and harsh conditions to trade off lignin’s structural complexity and limited solubility.Herein,we developed an oxidation system for lignin depolymerization using a single phosphomolybdic acid(H_(3)PMo_(12)O_(40))catalyst in acetic acid solvent to address the aforementioned issues.The entire catalytic system was operated under only 0.1 MPa O_(2) pressure,providing over 20 wt% of aromatic compounds containing aldehydes and carboxylic acids.Theoretical calculations combined with experimental analyses reveal structural transformations and redox behavior driven by the synergistic interaction between H_(3)PMo_(12)O_(40) and acetic acid.Mechanistic studies detected superoxide radicals,confirming the joint role of catalyst and solvent in oxygen activation,radicals stabilization,and enhanced reaction efficiency.A low-cost,commercially available catalyst with minimal oxygen demand offers a promising route to industrial-scale biomass refining.展开更多
A highly active catalyst of phosphomolybdic acid ~HPMo） was prepared and applied in the catalytic oxidative desulfurization （CODS） system. The catalyst was characterized by FT-IR, XRD, XPS and superconducting NMR. ...A highly active catalyst of phosphomolybdic acid ~HPMo） was prepared and applied in the catalytic oxidative desulfurization （CODS） system. The catalyst was characterized by FT-IR, XRD, XPS and superconducting NMR. The influences of rn（catalyst）/m（oil）, V（H202）fV（oil）, reaction temperature and reaction time on the fractional conversion of benzothiophene （BT） and dibenzothiophene （DBT） were investigated. GC-MS and micra-coulometric methods were employed to investigate the reaction. The catalyst has high desulfurization activity in the removal of BT and DBT under mild conditions. The recycling experiments indicated that DBT and BT removal could still reach 95.2% and 95.7% after 10 cycles.展开更多
This article describes a fast and simple electrochemical assay for detecting cell concentration.After cell death,the membrane of cells will be broken,and DNA molecules contained in the cells will be released,but this ...This article describes a fast and simple electrochemical assay for detecting cell concentration.After cell death,the membrane of cells will be broken,and DNA molecules contained in the cells will be released,but this does not happen in living cells.Sodium molybdate can react with the phosphate backbone of the released DNA molecules to form phosphomolybdate precipitation and produces a corresponding redox current.The higher the concentration of DNA,the stronger the intensity of the current generated.Sodium molybdate solution and centrifuged cell supernatant were added onto the glassy carbon electrode to determine the cell concentration by measuring the current intensity.The cell viability,which means the ratio of living cells to the total cells,can also be determined by this method.This assay has the advantages of high sensitivity,low detection limit,and wide detection range.In addition,this method was successfully applied to the detection of cell concentration in human serum,which has potential clinical applications.展开更多
A kind of inorganic-organic hybrid semiconductor composite nanoparticles： Dawson-type phosphomolybdate- doped polypyrrole （P2Mo18-PPy） was designed and prepared using microemulsion oxidation-polymerization at room ...A kind of inorganic-organic hybrid semiconductor composite nanoparticles： Dawson-type phosphomolybdate- doped polypyrrole （P2Mo18-PPy） was designed and prepared using microemulsion oxidation-polymerization at room temperature and characterized by TEM and IR. The P2Mo18-PPy was used as a bulk-modifier to fabricate a chemically modified carbon paste electrode（CPE） by direct mixing, which represents the example of polyoxometalates（ POMs）- doped semiconductor polymer nanoparticles modified electrode. Both the advantage of POMs-doped polymer and the surface-renewal property of the CPE were fully utilized. The electrochemical behavior of the P2Mo18-PPY bulk-modified CPE（P2Mo18-PPy-CPE） was investigated with cyclic voltammetry. Three couples of reversible redox peaks were observed in the range from ＋ 800 to 0 mV, which corresponded to the reduction and oxidation through two-, four- and six-electron processes, respectively. The P2 Mo18-PPY-CPE showed a high electrocatalytic activity for the reduction of nitrite, which expanded the application of POMs-doped semiconductor polymer nanoparticles.展开更多
The conjugated organic molecules modified hourglass-shaped Co{P_(4)Mo_(6)}_(2)-phosphomolybdate hybrid with the formula of(H_(2)L1)_(2)(H_(2)L2)[Co(H_(2)O)_(4)]{Co[P_(4)Mo_(6)O_(31)H_(7)]_(2)}·4H_(2)O(L1=2,2'...The conjugated organic molecules modified hourglass-shaped Co{P_(4)Mo_(6)}_(2)-phosphomolybdate hybrid with the formula of(H_(2)L1)_(2)(H_(2)L2)[Co(H_(2)O)_(4)]{Co[P_(4)Mo_(6)O_(31)H_(7)]_(2)}·4H_(2)O(L1=2,2'-dimethyl-6,6'-biquinoline,L2=4,4'-diaminobiphenyl)was synthesized via the hydrothermal method and applied in the photocatalytic reduction of hexavalent chromium Cr(Ⅵ).Experimental results indicate that this hybrid is composed of 1D chains formed by Co{P_(4)Mo_(6)}_(2)phosphomolybdate anionics connected via single-bridged[Co(H_(2)O)_(4)]^(2+)cations,which further interact with conjugated organic molecules L1 and L2 via hydrogen bonds to form the 3D supramolecular structure.This hybrid exhibits an extensive absorption of visible light,coupled with an appropriate energy band structure,which contribute to its remarkable photocatalytic performance in the reduction of Cr(Ⅵ).Within 120 min,the reduction conversion of Cr(Ⅵ)can reach 86%.Moreover,this hybrid still shows excellent catalytic performance in actual aqueous samples,revealing its strong potential for practical applications.The mechanism of photocatalytic reduction reaction was further studied.This work provides a new method for designing efficient polyoxometalate-based photocatalysts for Cr(Ⅵ)reduction.展开更多
TiO2 nanotube arrays were prepared by means of an electrochemical anodization technique in an organic electrolyte solution doped with polyvinyl pyrrolidone (PVP) and were subsequently modified with phosphomolybdic aci...TiO2 nanotube arrays were prepared by means of an electrochemical anodization technique in an organic electrolyte solution doped with polyvinyl pyrrolidone (PVP) and were subsequently modified with phosphomolybdic acid (PMoA) to obtain PMoA/TiO2 nanotube arrays. The microstructure and photochromic properties were investigated via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results indicated that the Keggin structure of PMoA and the nanotube structure of TiO2 were not destroyed, and there was a strong degree of interaction between PMoA and TiO2 at the biphasic interface with lattice interlacing during the compositing process. The XPS results further indicated that there was a change in the chemical microenvironment during the formation process of the composite, and a new charge transfer bridge was formed through the Mo-O-Ti bond. Under visible light irradiation, the colorless PMoA/TiO2 nanotube array quickly turned blue and exhibited a photochromic response together with reversible photochromism in the presence of H2O2. After visible light irradiation for 60s, the appearance of Mo^5+ species in the XPS spectra indicated a photoreduction process in accordance with a photoinduced electron transfer mechanism.展开更多
Heteropoly acid of Keggin structure phosphotungstic（HPW） and phosphomolybdic（HPMo） were chemically anchored to the modified SBA-15 channel. The materials were used as catalyst for oxidative desulfurization of orga...Heteropoly acid of Keggin structure phosphotungstic（HPW） and phosphomolybdic（HPMo） were chemically anchored to the modified SBA-15 channel. The materials were used as catalyst for oxidative desulfurization of organic sulfur compounds including benzothiophene （BT）, dibenzothiophene （DBT） and 4,6-dimethydibenzothiophene （4,6-DMDBT）. The experimental results show that the catalysts are efficient and reusable, the catalytic activity is hardly reduced even in the 5th cycle of use.展开更多
A novel mesoporous HPMo/SiO2 composite was synthesized by the sol-gel method with triblock copolymer EO20PO70EO20 as template.The properties of the product were characterized by X-ray diffraction,transmission electron...A novel mesoporous HPMo/SiO2 composite was synthesized by the sol-gel method with triblock copolymer EO20PO70EO20 as template.The properties of the product were characterized by X-ray diffraction,transmission electron microscopy,N2 adsorption-desorption isotherms,Fourier transform infrared spectrometer and inductively-coupled plasma analysis.The experimental results show that the product has a very ordered hexagonal mesostructure,and the HPMo is immobilized into the framework of silica.The final mesoporous composite shows excellent stability in polar solvents.Results of catalytic tests indicate that the composite is an effective catalyst for oxidation of dibenzothiophen,and there are few activity losses even after the third cycle of uses.The high catalytic activity and good insolubility make it a promising catalyst in oxidative desulfurization process.展开更多
Hybrid proton conducting membranes of poly（vinyl alcohol） （PVA） and phosphomolybdic acid （PMA） were prepared by solution casting method. The effect of PMA doping and PVA crosslinking density on the membrane prop...Hybrid proton conducting membranes of poly（vinyl alcohol） （PVA） and phosphomolybdic acid （PMA） were prepared by solution casting method. The effect of PMA doping and PVA crosslinking density on the membrane properties and proton conductivity were investigated. The crosslinking reaction between the hydroxyl group of PVA and the aldehyde group of glutaraldehyde （GA） was characterized by IR spectroscopy. Proton conductivity of the membranes increases with an increase in concentration of the doped PMA and also with an increase in crosslinking density of the membranes. Proton conductivity results indicate that a significant amount of PMA was maintained in the membranes even after several hours of immersion in water. A maximum conductivity of 0.0101 S cm^-1 was obtained for the membrane with 33.3 wt% PMA and crosslinking density of 5.825 mol%. X-ray diffraction studies were carried out to investigate the influence of PMA doping and crosslinking density on the nature of the membranes. These properties make them very good candidates for polymer electrolyte membranes for direct methanol fuel cell application.展开更多
In this work, the removal of thiophene from simulated oil has been studied by using the adsorption, extraction and oxidation/adsorption methods, respectively. In the adsorptive desulfurization process, different comme...In this work, the removal of thiophene from simulated oil has been studied by using the adsorption, extraction and oxidation/adsorption methods, respectively. In the adsorptive desulfurization process, different commercial adsorbents were used to eliminate thiophene at ambient pressure and mild temperature, and the results showed that carbon powder had the best adsorption ability. In the extractive desulfurization process, the best desulfurization result was obtained when DMF is used. In the oxidative/adsorptive desulfurization procedure using synthesized potassium ferrate as the oxidant and phosphomolybdic acid solution as the catalyst, thiophene was oxidized and removed from hydrocarbons in combination with active carbon adsorption, and the residual sulfur content of simulated oil could be reduced to 15.3mg/L from the original level of 200mg/L, with the desulfurization rate reaching 92.3%.展开更多
The existence of alkali metals in fl ue gases originating from stationary sources can result in catalyst deactivation in the low-temperature selective catalytic reduction(SCR)of nitrogen oxides(NO_(x)).It is widely ac...The existence of alkali metals in fl ue gases originating from stationary sources can result in catalyst deactivation in the low-temperature selective catalytic reduction(SCR)of nitrogen oxides(NO_(x)).It is widely accepted that alkali metal poisoning causes damage to the acidic sites of catalysts.Therefore,in this study,a series of CoMn catalysts doped with heteropolyacids(HPAs)were prepared using the coprecipitation method.Among these,CoMnHPMo exhibited superior catalytic performance for SCR and over 95%NO_(x) conversion at 150-300.Moreover,it exhibited excellent catalytic activity and stability after alkali poisoning,demonstrating outstanding alkali metal resistance.The characterization indicated that HPMo increased the specifi c surface area of the catalyst,which provided abundant adsorption sites for NO_(x) and NH_(3).Comparing catalysts before and after poisoning,CoMnHPMo enhanced its alkali metal resistance by sacrifi cing Brønsted acid sites to protect its Lewis acid sites.In situ DRIFTS was used to study the reaction pathways of the catalysts.The results showed that CoMnHPMo maintained high NH_(3) adsorption capacity after K poisoning and then reacted rapidly with NO intermediates to ensure that the active sites were not covered.Consequently,SCR performance was ensured even after alkali metal poisoning.In sum-mary,this research proposed a simple method for the design of an alkali-resistant NH_(3)-SCR catalyst with high activity at low temperatures.展开更多
文摘A metal-organic framework/inorganic composite(ZIF-8@AMP)was synthesized by the in situ introduction of the active component ammonium phosphomolybdate(AMP)during the ambient solution-phase synthesis of the metal-organic framework(ZIF-8).The structure and properties of the composite were characterized using scanning electron microscopy(SEM),X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TGA),and Fourier transform infrared spectroscopy(FTIR).Its adsorption performance for Rb^(+)and Cs^(+)in water was investigated.Results indicate that ZIF-8@AMP exhibited adsorption efficiencies of 93.5%and 95.6%for Rb^(+)and Cs^(+)within 30 min,with maximum adsorption capacities of 92.7 and 104.5 mg·g^(-1),respectively.After five adsorption-desorption cycles,it maintained high adsorption capacity and achieved over 84.9%adsorption efficiency for Rb^(+)and Cs^(+)in actual brine samples.The adsorption of ZIF-8@AMP for Rb^(+)and Cs^(+)follows pseudosecond-order kinetics and the Langmuir adsorption isotherm,indicating an endothermic,entropy-increasing,and spontaneous process.The adsorption mechanism involves electrostatic attraction and ion exchange between ZIF-8@AMP and Rb^(+)and Cs^(+).
文摘Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.
文摘Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by BET method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9℃/min. FePMo12 was found to be a more active catalyst for propene （17.2% yield） with minimal over deep oxidation （0.3% yield in COx）.
基金financially supported by the National Natural Science Foundation of China(Nos.21871076 and21901060)the Natural Science Foundation of Hebei Province(Nos.B2022205005,B2020205008,B2019205074 and B2016205051)+3 种基金the Nature Science Foundation of Hebei Education Department(No.BJ2020037)the Innovation Capability Improvement Plan Project of Hebei Province(No.22567604H)China Postdoctoral Science Foundation funded project(No.2021TQ0095)the Science Foundation of Hebei Normal University(No.L2019B15)。
文摘Abstra ct Utilizing efficient and durable photocatalysts for the removal of carcinogen Cr(Ⅵ)in wide pH water environment is of great significance for environment remediation.Herein,three conjugated organic component-functionalized hourglass-type phosphomolybdate hybrids with the formulas(H_(2)DBQ)[Fe(-H_(2)O)_(3)]_(2){Fe[P_(4)Mo_(6)0_(31)H_(7)]_(2)}·7H_(2)O(1),(H_(2)DBQ)_(2)(H_(2)DBP)[Fe(H_(2)O)_(4)]{Fe[P_(4)Mo_(6)O_(31)H_(7)]_(2)}·4H_(2)O(2),(H_(2)DBP)_(2){Fe[P_(4-)Mo_(6)O_(31)H_(9)]_(2)}·10H_(2)O(3)(DBQ=2,2'-dimehyl-6,6'-biquinoline;DBP=4,4'-diaminobiphenyl)were synthesized via hydrothermal method as photocatalysts for reducing Cr(Ⅵ)under visible light illumination.Structure analysis showed that hybrids 1-3 consist of hourglass-type[Fe(P_(4)Mo_(6)O_(31)H_(6))_(2)]^(10)-(abbr.Fe{P_(4)Mo_(6)}_(2))poly anionic clusters functionalized with different proportional of conjugated organic components(DBQ and DBP)effectively regulated their visible-light absorption capabilities and electron structures,which could be employed to reflect the structure-activity relationship of materials.When used as catalysts for reducing Cr(Ⅵ),hybrids 1-3 displayed distinct photocatalytic activities with Cr(Ⅵ)removal efficiencies of 91%,86%and 81%with only 10 W of white light being used as illumination,which are superior to that of pristine Fe{P_(4)Mo_(6)}_(2)salt(62%).Moreover,hybrid 1 also maintained high Cr(Ⅵ)removal efficiencies above~85%and high structural stabilities in solutions with wide pH ranges of2.5-10.0.Mechanism investigation showed that the higher organic component conjugation levels could promote the optic al absorption and facilitate the electron transfer between Fe{P_(4)Mo_(6)}_(2)and org anic components,thus resulting in effective Cr(Ⅵ)reduction photocatalytic efficacy.This work provides a viable way to design the photocatalysts based on polyoxometalates for removing wastewater pollutants.
基金supported by the National Natural Science Foundation of China(Nos.21871076.21901060)Natural Science Foundation of Hebei Province(Nos.B2016205051,B2020205008 and B2019205074)+2 种基金Science and Technology Project of Hebei Education Department(No.BJ2020037)Project funded by China Postdoctoral Science Foundation(No.2021TQ0095)the Science Foundation of Hebei Normal University(No.L2019B15).
文摘Photo-assisted electrochemical technique provides a promising approach towards carcinogen chromium(Ⅵ)detection,which requires reasonable catalyst design.Herein,an unusual hexa-nuclear cadmium cluster functionalized reductive phosphomolybdate hybrid as photo-electrochemical sensor was designed and synthesized with formula of{[Cd(H_(2)O)_(2)]_(2)[Cd(btmbp)]_(2)}{Cd(P_(4)Mo_(6)O_(31)H_(7))_(2)}·20H_(2)O(1)(btmbp=4,4′-bis((^(1)H-1,2,4-triazol-1-yl)methyl)biphenyl),in which the photoactive hexa-nuclear{Cd_(6)}clusters cooperated with reductive phosphomolybdate[P_(4)Mo_(6)O_(31)]^(12)−endow the material with wide light absorption and remarkable redox activity,thus achieving efficient photo-assisted electrochemical Cr(Ⅵ)detection performance.Under visible-light assistance,the detection limit(LOD)and sensitivity of Cr(Ⅵ)is 4.17 nmol/L(0.225 ppb)and 226.32μA L/μmol,which is apparently superior to the performance without photo-assistance(6.25 nmol/L and 106.95μA L/μmol)and far satisfies the demands of world health organization(WHO)for potable water(50 ppb).Moreover,compound 1 showed prominent Cr(Ⅵ)detection performance in practical water samples together with remarkable anti-interference capacity and good electrochemical durability.This work provides an important guidance for designing efficient polyoxometalate-based crystalline sensors for Cr(Ⅵ)detection.
基金This project was supported by the NNSFC (No 20771023)the State 863 Program Project (No 2007AA03z218)Analysis and Testing Foundation of Northeast Normal University
文摘A novel compound [H-IDP]4[PMo12O40]·8H2O 1 based on Keggin-type phosphor- molybdate has been synthesized by hydrothermal method and characterized by IR spectroscopy, elemental analyses and single-crystal X-ray diffraction. The composite crystallizes in the mono- clinic system, space group C2/m with a = 13.937（5）, b = 27.033（5）, c = 10.857（5） A, β = 122.489（5）°, V = 3450（2）A^3, Mr = 2611.11, Z = 2, Dc = 2.498 g/cm^3, F（000） = 2486,μ = 2.243 mm^-1, the final R = 0.0568 and wR = 0.1216 for 2707 observed reflections with I 〉 2σ（I）. X-ray structural study shows that 1 consists of a [PMo12O40]^4- polyanion, four protonated IDP cations and eight H2O molecules. In the structure of 1, a 3D network forms by hydrogen bond of [PMo12O40]^4- polyanion, HIDP^＋ cation and H2O molecules. Upon excitation wavelength of 280 nrn in hydroxylic solvents at room temperature, 1 shows fluorescence property.
文摘Phospbomolybdate （PMo） with varying Mo loadings ranging from 5-30 wt% on alumina were prepared by incipient wetness impregnation method. 0.5 wt% of Pt was further loaded in order to prepare the bifunctional （metal-acid） Pt-PMo/Al2O3 catalysts. Thus prepared catalysts showed very high catalytic activities for n-heptane hydroisomerization compared with Pt impregnated MoO3 catalysts supported either on Al2O3 or on AIPO4. The conversion of n-heptane increased with Mo loading up to 20 wt% and slightly decreased with further Mo loading. However, the selectivity towards isomers showed an increasing trend up to 30 wt% of Mo in the catalyst. A relationship between catalytic activity and acidic strength was established in the present study.
文摘Transition-metal substituted Keggin-type polyoxometalates(POMs)are of great interest for applications in biomedicine,material science,and catalysis.The synthesis of transition metal-substituted Keggin-type polytungstates via the formation of a lacunary structure is well established,in contrast this approach is so far unexplored for Keggin-type polymolybdates.This is because the prevailing doctrine assumes that the lacunary Keggin phosphomolybdate[PMo_(9)O_(34)]^(9−)is too unstable and can only be stabilized with organic ligands such as pyridine in organic solvents.In this work,we present a reliable procedure for the synthesis of the lacunary compound[PMo_(9)O_(34)]^(9−)and its application in a novel in situ approach for the synthesis of different metal substituted POMs.The method is based on generating the lacunary species in situ,where the metal-substituted POMs are produced by adding another precursor compound.We employed this method to synthesize several new specific element-substituted POMs,which we present with comprehensive characterization.The interpretation of the analytical results was complemented by DFT calculations.For the separation of by-products from synthesis,we employed a novel membrane-based nanofiltration process,that enables superior separation of alkali salts from the POM solution resulting in>99%rejection of the POM components.
基金supported by National Natural Science Foundation of China(21303010)Opening Project of Key Laboratory of Polyoxometalate Science of Ministry of Education(130028720).
文摘With hydrogen bond-directed three-dimensional phosphomolybdate-based supramolecular architecture as a precursor,a Mo_(2)C composite material(Mo_(2)C@NC)supported by nitrogen-doped carbon matrix was fabricated successfully through calcination.In this composite material,Mo_(2)C particles with size about 5 to 8 nm disperse evenly in the framework of nitrogen-doped mesoporous carbon matrix.In acid media,to achieve a current density of 10 mA cm^(-2),the overpotential required was 142 mV with a Tafel slope of 63 mV dec−1.Under basic conditions,the overpotential reduced to as low as 56 mV with a Tafel slope of 59 mV dec−1.To realize overall water splitting,MoO_(2)-based composite material(MoO_(2)@NC)with nitrogen-doped carbon as matrix was obtained using the same precursor as Mo_(2)C@NC.MoO_(2)@NC exhibits excellent oxygen evolution reaction(OER)performance with an over potential of 302 mV.With Mo_(2)C@NC as cathode and MoO_(2)@NC as anode,an efficient electrolyzer was constructed,which required a cell voltage of 1.60 V to achieve a current of 10 mA cm^(-2) in 1.0 M KOH.Furthermore,besides overall water splitting,Mo_(2)C@NC also shows striking catalytic removal property towards 4-nitrophenol and Rhodamine B.
文摘Oxidative catalysis enables lignin depolymerization to yield carbonyl-containing aromatic chemicals for sustainable lignocellulose valorization.The oxidative depolymerization of lignin requires high oxygen pressure and harsh conditions to trade off lignin’s structural complexity and limited solubility.Herein,we developed an oxidation system for lignin depolymerization using a single phosphomolybdic acid(H_(3)PMo_(12)O_(40))catalyst in acetic acid solvent to address the aforementioned issues.The entire catalytic system was operated under only 0.1 MPa O_(2) pressure,providing over 20 wt% of aromatic compounds containing aldehydes and carboxylic acids.Theoretical calculations combined with experimental analyses reveal structural transformations and redox behavior driven by the synergistic interaction between H_(3)PMo_(12)O_(40) and acetic acid.Mechanistic studies detected superoxide radicals,confirming the joint role of catalyst and solvent in oxygen activation,radicals stabilization,and enhanced reaction efficiency.A low-cost,commercially available catalyst with minimal oxygen demand offers a promising route to industrial-scale biomass refining.
基金supported by the National Natural Science Foundation of China (21473126)~~
文摘A highly active catalyst of phosphomolybdic acid ~HPMo） was prepared and applied in the catalytic oxidative desulfurization （CODS） system. The catalyst was characterized by FT-IR, XRD, XPS and superconducting NMR. The influences of rn（catalyst）/m（oil）, V（H202）fV（oil）, reaction temperature and reaction time on the fractional conversion of benzothiophene （BT） and dibenzothiophene （DBT） were investigated. GC-MS and micra-coulometric methods were employed to investigate the reaction. The catalyst has high desulfurization activity in the removal of BT and DBT under mild conditions. The recycling experiments indicated that DBT and BT removal could still reach 95.2% and 95.7% after 10 cycles.
基金supported by the National Natural Science Foundation of China(No.21575165)。
文摘This article describes a fast and simple electrochemical assay for detecting cell concentration.After cell death,the membrane of cells will be broken,and DNA molecules contained in the cells will be released,but this does not happen in living cells.Sodium molybdate can react with the phosphate backbone of the released DNA molecules to form phosphomolybdate precipitation and produces a corresponding redox current.The higher the concentration of DNA,the stronger the intensity of the current generated.Sodium molybdate solution and centrifuged cell supernatant were added onto the glassy carbon electrode to determine the cell concentration by measuring the current intensity.The cell viability,which means the ratio of living cells to the total cells,can also be determined by this method.This assay has the advantages of high sensitivity,low detection limit,and wide detection range.In addition,this method was successfully applied to the detection of cell concentration in human serum,which has potential clinical applications.
基金Supported by Natural Science Foundation of Liaoning Province(No. 20032138) and Education Committee Foundation of Liaon-ing Province(No. 2004F023).
文摘A kind of inorganic-organic hybrid semiconductor composite nanoparticles： Dawson-type phosphomolybdate- doped polypyrrole （P2Mo18-PPy） was designed and prepared using microemulsion oxidation-polymerization at room temperature and characterized by TEM and IR. The P2Mo18-PPy was used as a bulk-modifier to fabricate a chemically modified carbon paste electrode（CPE） by direct mixing, which represents the example of polyoxometalates（ POMs）- doped semiconductor polymer nanoparticles modified electrode. Both the advantage of POMs-doped polymer and the surface-renewal property of the CPE were fully utilized. The electrochemical behavior of the P2Mo18-PPY bulk-modified CPE（P2Mo18-PPy-CPE） was investigated with cyclic voltammetry. Three couples of reversible redox peaks were observed in the range from ＋ 800 to 0 mV, which corresponded to the reduction and oxidation through two-, four- and six-electron processes, respectively. The P2 Mo18-PPY-CPE showed a high electrocatalytic activity for the reduction of nitrite, which expanded the application of POMs-doped semiconductor polymer nanoparticles.
基金supported by the National Natural Science Foundation of China(22471056,22301058,22371065,21901060,and 21871076)the Natural Science Foundation of Hebei Province(B2024205033,B2024205007,B2022205005,and B2020205008)+6 种基金the Science and Technology Project of Hebei Education Department(QN2023049)the China Postdoctoral Science Foundation funded project(2021TQ0095)the Project of Science and Technology Department of Hebei Province(22567622H)the Science Foundation of Hebei Normal University(L2023B51)the Graduate Innovation Ability Cultivation Funding Project of Hebei Province(CXZZBS2024093)College Student Science and Technology Innovation Project of Hebei Province(202410094022)the Chemistry Postdoctoral Research Station at Hebei Normal University
文摘The conjugated organic molecules modified hourglass-shaped Co{P_(4)Mo_(6)}_(2)-phosphomolybdate hybrid with the formula of(H_(2)L1)_(2)(H_(2)L2)[Co(H_(2)O)_(4)]{Co[P_(4)Mo_(6)O_(31)H_(7)]_(2)}·4H_(2)O(L1=2,2'-dimethyl-6,6'-biquinoline,L2=4,4'-diaminobiphenyl)was synthesized via the hydrothermal method and applied in the photocatalytic reduction of hexavalent chromium Cr(Ⅵ).Experimental results indicate that this hybrid is composed of 1D chains formed by Co{P_(4)Mo_(6)}_(2)phosphomolybdate anionics connected via single-bridged[Co(H_(2)O)_(4)]^(2+)cations,which further interact with conjugated organic molecules L1 and L2 via hydrogen bonds to form the 3D supramolecular structure.This hybrid exhibits an extensive absorption of visible light,coupled with an appropriate energy band structure,which contribute to its remarkable photocatalytic performance in the reduction of Cr(Ⅵ).Within 120 min,the reduction conversion of Cr(Ⅵ)can reach 86%.Moreover,this hybrid still shows excellent catalytic performance in actual aqueous samples,revealing its strong potential for practical applications.The mechanism of photocatalytic reduction reaction was further studied.This work provides a new method for designing efficient polyoxometalate-based photocatalysts for Cr(Ⅵ)reduction.
基金supported by the National Natural Science Foundation of China (No.61774073)Open Project of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University (No. 2016-25)Science and Technology Development Program of Jilin province (No. 20170101086JC)
文摘TiO2 nanotube arrays were prepared by means of an electrochemical anodization technique in an organic electrolyte solution doped with polyvinyl pyrrolidone (PVP) and were subsequently modified with phosphomolybdic acid (PMoA) to obtain PMoA/TiO2 nanotube arrays. The microstructure and photochromic properties were investigated via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results indicated that the Keggin structure of PMoA and the nanotube structure of TiO2 were not destroyed, and there was a strong degree of interaction between PMoA and TiO2 at the biphasic interface with lattice interlacing during the compositing process. The XPS results further indicated that there was a change in the chemical microenvironment during the formation process of the composite, and a new charge transfer bridge was formed through the Mo-O-Ti bond. Under visible light irradiation, the colorless PMoA/TiO2 nanotube array quickly turned blue and exhibited a photochromic response together with reversible photochromism in the presence of H2O2. After visible light irradiation for 60s, the appearance of Mo^5+ species in the XPS spectra indicated a photoreduction process in accordance with a photoinduced electron transfer mechanism.
基金the National Natural Science Foundation of China (No.50272048)
文摘Heteropoly acid of Keggin structure phosphotungstic（HPW） and phosphomolybdic（HPMo） were chemically anchored to the modified SBA-15 channel. The materials were used as catalyst for oxidative desulfurization of organic sulfur compounds including benzothiophene （BT）, dibenzothiophene （DBT） and 4,6-dimethydibenzothiophene （4,6-DMDBT）. The experimental results show that the catalysts are efficient and reusable, the catalytic activity is hardly reduced even in the 5th cycle of use.
基金Funded by the Hubei Provincial Department of Education Science and Technology Program for Outstanding Young Talents (Q20081209)
文摘A novel mesoporous HPMo/SiO2 composite was synthesized by the sol-gel method with triblock copolymer EO20PO70EO20 as template.The properties of the product were characterized by X-ray diffraction,transmission electron microscopy,N2 adsorption-desorption isotherms,Fourier transform infrared spectrometer and inductively-coupled plasma analysis.The experimental results show that the product has a very ordered hexagonal mesostructure,and the HPMo is immobilized into the framework of silica.The final mesoporous composite shows excellent stability in polar solvents.Results of catalytic tests indicate that the composite is an effective catalyst for oxidation of dibenzothiophen,and there are few activity losses even after the third cycle of uses.The high catalytic activity and good insolubility make it a promising catalyst in oxidative desulfurization process.
文摘Hybrid proton conducting membranes of poly（vinyl alcohol） （PVA） and phosphomolybdic acid （PMA） were prepared by solution casting method. The effect of PMA doping and PVA crosslinking density on the membrane properties and proton conductivity were investigated. The crosslinking reaction between the hydroxyl group of PVA and the aldehyde group of glutaraldehyde （GA） was characterized by IR spectroscopy. Proton conductivity of the membranes increases with an increase in concentration of the doped PMA and also with an increase in crosslinking density of the membranes. Proton conductivity results indicate that a significant amount of PMA was maintained in the membranes even after several hours of immersion in water. A maximum conductivity of 0.0101 S cm^-1 was obtained for the membrane with 33.3 wt% PMA and crosslinking density of 5.825 mol%. X-ray diffraction studies were carried out to investigate the influence of PMA doping and crosslinking density on the nature of the membranes. These properties make them very good candidates for polymer electrolyte membranes for direct methanol fuel cell application.
基金financially supported by the Science and Technology Program of the Department of Education,Heilongjiang Province(11531012)
文摘In this work, the removal of thiophene from simulated oil has been studied by using the adsorption, extraction and oxidation/adsorption methods, respectively. In the adsorptive desulfurization process, different commercial adsorbents were used to eliminate thiophene at ambient pressure and mild temperature, and the results showed that carbon powder had the best adsorption ability. In the extractive desulfurization process, the best desulfurization result was obtained when DMF is used. In the oxidative/adsorptive desulfurization procedure using synthesized potassium ferrate as the oxidant and phosphomolybdic acid solution as the catalyst, thiophene was oxidized and removed from hydrocarbons in combination with active carbon adsorption, and the residual sulfur content of simulated oil could be reduced to 15.3mg/L from the original level of 200mg/L, with the desulfurization rate reaching 92.3%.
基金This work was supported by the National Key R&D Program of China(Nos.2022YFB3504100 and 2022YFB3504102)Natural National Science Foundation of China(No.22276133)+1 种基金Natural National Science Foundation of China(No.U20A20132)Natural National Science Foundation of China(No.52106180).
文摘The existence of alkali metals in fl ue gases originating from stationary sources can result in catalyst deactivation in the low-temperature selective catalytic reduction(SCR)of nitrogen oxides(NO_(x)).It is widely accepted that alkali metal poisoning causes damage to the acidic sites of catalysts.Therefore,in this study,a series of CoMn catalysts doped with heteropolyacids(HPAs)were prepared using the coprecipitation method.Among these,CoMnHPMo exhibited superior catalytic performance for SCR and over 95%NO_(x) conversion at 150-300.Moreover,it exhibited excellent catalytic activity and stability after alkali poisoning,demonstrating outstanding alkali metal resistance.The characterization indicated that HPMo increased the specifi c surface area of the catalyst,which provided abundant adsorption sites for NO_(x) and NH_(3).Comparing catalysts before and after poisoning,CoMnHPMo enhanced its alkali metal resistance by sacrifi cing Brønsted acid sites to protect its Lewis acid sites.In situ DRIFTS was used to study the reaction pathways of the catalysts.The results showed that CoMnHPMo maintained high NH_(3) adsorption capacity after K poisoning and then reacted rapidly with NO intermediates to ensure that the active sites were not covered.Consequently,SCR performance was ensured even after alkali metal poisoning.In sum-mary,this research proposed a simple method for the design of an alkali-resistant NH_(3)-SCR catalyst with high activity at low temperatures.
