Xiao-Hong Wang

Production of Biodiesel Through Esterification Reaction Using Choline Exchanging Polytungstoboronic Acids as Temperature-Responsive Catalysts

Co-reporter:Siqi Yan;Tong Tong;Yue Li;Shifa Ullah Khan;Jing Zhao

Catalysis Surveys from Asia 2017 Volume 21( Issue 4) pp:151-159

Publication Date(Web):24 August 2017

DOI:10.1007/s10563-017-9232-3

High proton content polytungstoboronic acid H7BW11TiO40 (abbreviated as H7BW11Ti) had been prepared through titanium mono-substituted of H5BW12O40, which was evaluated in esterification of palmitic acid with methanol. H7BW11Ti could promote esterification reaction with almost 100% conversion of 417 mol/mol h TOF within very short time of 1 h at methanol/acid ratio of 25:1 under reaction temperature of 65 °C, which was attributed to the higher Brønsted acidity and cooperation of Lewis acidic site generating from Ti substituent. Limitation by its homogeneous performance, solidification of H7BW11Ti was designed via partial exchanging protons with choline cation (abbreviated as Ch+) to prepare a series of [(CH3)3NCH2CH2OH]nH7−nBW11TiO40 (abbreviated as ChnH7−nBW11Ti, n = 0 ~ 7). Among all solid catalysts, the highest efficiency had been achieved by with 99.0% conversion and 429 mol/mol h TOF within 50 min at 65 °C at methanol/acid ratio of 15:1. The comparable activity was attributed to the cooperation of Ch+—self-assembling to form nanoreactor with amphiphilic surrounding to concentrate substrates and to resist to water-poison, temperature-responsive property to control form changing between heterogeneous to homogenous. This temperature-responsive HPA catalyst was available for production of biodiesel through esterification reaction. In addition, Separation of such heteropolyacid catalysts was easy by the lowering the reaction temperature to room temperature without appreciable loss of its high performance, which were reused for more than six times.

Designation of choline functionalized polyoxometalates as highly active catalysts in aerobic desulfurization on a combined oxidation and extraction procedure

Co-reporter:Xia Yu, Meng Shi, Siqi Yan, Hang Wang, Xiaohong Wang, Wu Yang

Fuel 2017 Volume 207(Volume 207) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.fuel.2017.06.027

•Use of DESs like POMs catalytic system in desulfurization under aerobic conditions.•No needing of any sacrificial agent in oxidation.•Oxidation of sulfur and extraction of produced sulfone occurs in one-pot.•Higher stability and duration for such process with low-cost and greener.•Availability for production clean diesel and gasoline with super low S contents.Deep oxidation/extraction desulfurization from liquid fuels had been done via choline functionalized polyoxometalates (POMs) [(CH3)3NCH2CH2OH]xNa5−xIMo6O24 (abbreviated as ChxNa5−xIMo6O24, x = 1–5) and oxygen. By Ch5IMo6O24, organic sulfurs including dibenzothiophene (DBT), benzothiophene (BT), and 4, 6-dimethyldibenzothiophene (4, 6-DMDBT) could be oxidized with 99% conversion and 100% sulfone selectivity due to its deep eutectic solvent (DES)-like behavior and high activity of IMo6O245−. Noteworthily, thiophene was highly selectively oxidized with 96.8% conversion and no oxidation of alkane was found. Ch5IMo6O24 was also available for deep desulfurization for FCC gasoline and diesel to give almost clear products with extremely lower sulfur contents (2.73 and 10.8 ppm, respectively) without formation of by-products of oxidation to loss their octane values. The durable stability permitted it reusability.The choline functionalized polyoxometalate (POM) catalysts exhibited enhanced activity for oxidative desulfurization of DBT or other organic sulfurs through adsorption, oxidation and extraction effect, which were resulted from the synergistic effect of choline cation and POM anion.Download high-res image (79KB)Download full-size image

Efficient mineralization of phenol by a temperature-responsive polyoxometalate catalyst under wet peroxide oxidation at lower temperatures

Co-reporter:Yiming Li;Xueyan Zhang;Dan Zhang;Yue Li;Xiaohong Wang;Shengtian Wang

RSC Advances (2011-Present) 2017 vol. 7(Issue 69) pp:43681-43688

Publication Date(Web):2017/09/07

DOI:10.1039/C7RA08409A

Herein, a temperature-responsive polyoxometalate (POM) catalyst [C16H33(CH3)3N]3[PO4{WO(O2)2}4]/poly(N-isopropylacrylamide) (abbreviated as (C16PW(O2)2/PNIPAM) was prepared and used in the catalytic wet peroxide oxidation (CWPO) of phenol under mild conditions. The POM catalyst C16PW(O2)2/PNIPAM showed a higher degradation efficiency and mineralization of phenol with H2O2 at room temperature or even at lower temperature (0 °C) within a short time (120 min). The high efficiency at lower temperature was attributed to its temperature-responsive property, wherein the lattice of the temperature-sensitive polymer relaxed at lower temperature and then wrinkled at higher temperature. These characteristics also permitted C16PW(O2)2/PNIPAM to be easily separated for recycling. The leaching test indicated that the POM catalyst exhibited excellent stability and little leaching and can be used as a thermosensitive catalyst for about six times. C16PW(O2)2/PNIPAM has potential application in the CWPO of phenol without the limitation of temperature and pH conditions.

Efficient mineralization of phenol by a temperature-responsive polyoxometalate catalyst under wet peroxide oxidation at lower temperatures

Co-reporter:Yiming Li;Xueyan Zhang;Dan Zhang;Yue Li;Xiaohong Wang;Shengtian Wang

RSC Advances (2011-Present) 2017 vol. 7(Issue 69) pp:43681-43688

Publication Date(Web):2017/09/07

DOI:10.1039/C7RA08409A

Herein, a temperature-responsive polyoxometalate (POM) catalyst [C16H33(CH3)3N]3[PO4{WO(O2)2}4]/poly(N-isopropylacrylamide) (abbreviated as (C16PW(O2)2/PNIPAM) was prepared and used in the catalytic wet peroxide oxidation (CWPO) of phenol under mild conditions. The POM catalyst C16PW(O2)2/PNIPAM showed a higher degradation efficiency and mineralization of phenol with H2O2 at room temperature or even at lower temperature (0 °C) within a short time (120 min). The high efficiency at lower temperature was attributed to its temperature-responsive property, wherein the lattice of the temperature-sensitive polymer relaxed at lower temperature and then wrinkled at higher temperature. These characteristics also permitted C16PW(O2)2/PNIPAM to be easily separated for recycling. The leaching test indicated that the POM catalyst exhibited excellent stability and little leaching and can be used as a thermosensitive catalyst for about six times. C16PW(O2)2/PNIPAM has potential application in the CWPO of phenol without the limitation of temperature and pH conditions.

Decoration of chitosan microspheres with Brønsted heteropolyacids and Lewis ion Ti: trifunctional catalysts for esterification to biodiesel

Co-reporter:Tong Tong;Yiming Li;Rui Hou;Xiaohong Wang;Shengtian Wang

RSC Advances (2011-Present) 2017 vol. 7(Issue 67) pp:42422-42429

Publication Date(Web):2017/08/29

DOI:10.1039/C7RA07479D

H3PW12O40 is a commonly used Brønsted acid catalyst in esterification and transesterification reactions to produce biodiesel, whose homogeneous form and single acid sites lead to difficulties in separation and relatively less activity. Herein, the water-insoluble and multifunctional active sites based on H3PW12O40, chitosan and Ti4+ had been fabricated giving H3PW12O40/Ti/chitosan tri-functional hybrids. Such hybrids exhibited higher activity in esterification reactions due to the existence of Brønsted acid from H3PW12O40, Lewis acid from Ti4+, and base sites from the –NH2 group of chitosan, and all also due to the generation of pores in chitosan through introduction of the Ti ions. Furthermore, H3PW12O40/Ti/chitosan acted as heterogeneous catalysts and could be separated for reuse at least six times without significant loss of activity and with little leaching of Ti4+ and H3PW12O40 from the support chitosan.

Heteropolyacids embedded in a lipid bilayer covalently bonded to graphene oxide for the facile one-pot conversion of glycerol to lactic acid

Co-reporter:Meilin Tao;Ningyue Sun;Yiming Li;Tong Tong;Marika Wielicako;Shengtian Wang;Xiaohong Wang

Journal of Materials Chemistry A 2017 vol. 5(Issue 18) pp:8325-8333

Publication Date(Web):2017/05/10

DOI:10.1039/C7TA01334E

A new two-step strategy for the functionalization of graphene oxide (GO) with heteropolyacids (HPAs) and the catalytic activity of the so-obtained materials in the conversion of glycerol to lactic acid (LA) are reported. Covalent bonding of a a-NH–(CH2)2–NH2+–CH2(CH2)8CH3 lipid-like bilayer to the GO surface is followed by embedding of HPAs to give HPMo@lipid(n)/GO hybrid materials, where n represents the length of the diamine carbon chain (n = 2, 4, 6, 8, and 10). The HPAs are tightly surrounded by the lipid bilayer through electrostatic interactions with the protonated amine groups and are highly resistant to environmental changes and leaching from the GO. The hydrophilicity of HPAs and GO and the hydrophobic properties of the lipid bilayer can be easily controlled by changing the length of the alkyl chain, and the redox potential varies as the distance between HPAs and GO varies. The materials show excellent catalytic activity in glycerol cascade conversion to LA, with HPMo@lipid(4)/GO achieving the highest reported efficiency to date, with 90% yield at 97% conversion under mild conditions (1 M glycerol, 60 °C, 3.5 h, and 10 bar O2). Such high efficiency is attributed to the combination of suitable redox potentials, balanced hydrophilic and hydrophobic properties, and the capillary-like reactor formed by the wall of the lipid bilayer, which enhances the adsorption of O2 and glycerol around catalytic active sites. HPMo@lipid(4)/GO functions in the absence of an organic solvent and base, with a high concentration of glycerol (9.2 wt%) and in the presence of methanol and other impurities from biodiesel production, with crude glycerol giving almost 87% yield. No structural changes or leaching of HPAs from GO occurs during the reaction or with recycling up to fifteen times.

Lewis-acid-promoted catalytic cascade conversion of glycerol to lactic acid by polyoxometalates

Co-reporter:Meilin Tao, Dan Zhang, Xi Deng, Xiangyu Li, Junyou Shi and Xiaohong Wang

Chemical Communications 2016 vol. 52(Issue 16) pp:3332-3335

Publication Date(Web):19 Jan 2016

DOI:10.1039/C5CC10262F

The polyoxometalates AlPMo12O40 and CrPMo12O40 show high activity and reusablility for cascade conversion of glycerol directly to lactic acid under mild conditions without the addition of base, and can be reused more than 12 times with 90.5% selectivity at 93.7% conversion. AlPMo12O40 is tolerant to crude glycerol from biodiesel production.

Design of a Highly Efficient Indium-Exchanged Heteropolytungstic Acid for Glycerol Esterification with Acetic Acid

Co-reporter:Zhong Sun;Xixin Duan;Meilin Tao;Xiaohong Wang

Catalysis Surveys from Asia 2016 Volume 20( Issue 2) pp:82-90

Publication Date(Web):2016 June

DOI:10.1007/s10563-016-9209-7

A series of highly active, selective, and stable solid indium-exchanged tungstophosphoric acid catalysts had been prepared, characterized and evaluated for bio-derived glycerol esterification with acetic acid to produce valuable biofuel additives. It was found that the Inx/3H3−xPW with nanotube structure owns Lewis acidity and Brønsted acidity in one, which favors for the efficient esterification of glycerol into monoglycerides with higher selectivity. Among all, In0.8H0.6PW presented exceptionally high activity with 88 % conversion and 96 % selectivity to MAG within 30 min of reaction time at 120 °C using 4:1 molar ratio. The better performance came from its remarkable stability, due to the unique Keggin structure, high acidity as well as nanotube structure. In addition, this In0.8H0.6PW catalyst did not suffer from deactivation of water in the six consecutive reaction tests.

Lysine functional heteropolyacid nanospheres as bifunctional acid–base catalysts for cascade conversion of glucose to levulinic acid

Co-reporter:Zhong Sun, Shengtian Wang, Xiaohong Wang, Zijiang Jiang

Fuel 2016 Volume 164() pp:262-266

Publication Date(Web):15 January 2016

DOI:10.1016/j.fuel.2015.10.014

•Application of acid/base bifunctional HPA catalysts in glucose conversion.•The catalyst gave high yield of LA (52.6%) within 30 min at 130 °C using ChCl as solvent.•The catalyst performed as a heterogeneous catalyst in ChCl system.•Easily recycled by simple washing treatment.Acid–base bifunctional heteropolyacid (HPA) nanospheres (C6H15O2N2)3−xHxPW12O40 (abbreviated as Ly3−xHxPW) have been evaluated in cascade isomerization/dehydration of glucose to 5-hydroxymethylfurfural (HMF) or levulinic acid (LA) in choline chloride (ChCl) based on deep eutectic solvent system. Compared to other heterogeneous catalysts, the dehydration of glucose catalyzed by Ly0.5H2.5PW gave almost the best efficiency (75.1% conversion and 52.6% LA yield) within very short time (30 min) at 130 °C using ChCl as solvent. The main reason was its unique property of double Brønsted acidity and base property, while the base sites were main candidate for isomerization of glucose to fructose; in addition, the Brønsted acidity might promote the conversion of glucose to product LA rather than HMF. Moreover, this catalyst was suitable for high concentrated glucose (up to 66.7 wt.%) conversion which was obtained after the additive of ChCl. Ly0.5H2.5PW was easily recovered and recycled by simple washing treatment.

A heteropoly acid ionic crystal containing Cr as an active catalyst for dehydration of monosaccharides to produce 5-HMF in water

Co-reporter:Xiaohu Yi, Irina Delidovich, Zhong Sun, Shengtian Wang, Xiaohong Wang and Regina Palkovits

Catalysis Science & Technology 2015 vol. 5(Issue 4) pp:2496-2502

Publication Date(Web):17 Feb 2015

DOI:10.1039/C4CY01555J

Cs2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40], a chromium-based heteropoly acid (HPA) ionic crystal, was demonstrated to be an active heterogeneous catalyst for production of 5-hydroxymethylfurfural (HMF) from fructose or glucose. The dependencies of catalytic activity on reaction parameters such as solvent, temperature and reaction time were investigated and the reaction conditions were optimized. Based on fructose, the yield of HMF reaches 86% and 56% when using DMSO and water as solvents, respectively. Starting from glucose, a yield of HMF up to 48% can be achieved for both aqueous and DMSO media. The catalyst was successfully recycled 5 times.

Fabrication of sulfonated carbon catalyst from biomass waste and its use for glycerol esterification

Co-reporter:Mei-Lin Tao, Hong-Yu Guan, Xiao-Hong Wang, Yi-Chun Liu, Rong-Fuh Louh

Fuel Processing Technology 2015 Volume 138() pp:355-360

Publication Date(Web):October 2015

DOI:10.1016/j.fuproc.2015.06.021

•Sulfonated carbon catalysts were prepared by sulfonating a biomass waste.•100% conversion of glycerol and a maximum ester yield were obtained in short time.•Selectivity of glyceride can be controlled by adjusting acid strength of the catalyst.•This catalyst did not suffer from deactivation after six recycles.Sulfonated carbon catalysts were prepared by sulfonation of carbonized catkins from willow under different sulfonated conditions. Such materials were characterized by SEM, EDS, FTIR and TGA. The results indicated that sulfonated conditions might influence the acid density of the sulfonated carbon catalysts, but did not influence the microtubular structure. These sulfonated carbon catalysts exhibited high acid capacity, good thermal stability and better catalytic activity for the glycerol esterification. With a molar ratio of acetic acid to glycerol of 5:1, a catalyst amount of 5 wt.% and a reaction temperature of 393 K for 2 h, glycerol was almost completely transformed into a mixture of glycerol esters including monoacetate, diacetate and triacetate. Controlling of acid density of the catalysts and reaction conditions could obtain highly desired products. Meanwhile, the hydrophobic property of these sulfonated carbon catalysts led to some tolerance to water. Moreover, excellent reusability of the catalyst was also confirmed by repeated experiments.

Aerobic oxidation of starch catalyzed by isopolyoxovanadate Na4Co(H2O)6V10O28

Co-reporter:Xiaoli Chen, Siqi Yan, Hang Wang, Zhiyun Hu, Xiaohong Wang, Mingxin Huo

Carbohydrate Polymers 2015 Volume 117() pp:673-680

Publication Date(Web):6 March 2015

DOI:10.1016/j.carbpol.2014.10.066

•Prepared catalyst Na4Co(H2O)6V10O28 and applied in partial oxidation of starch.•Oxidation of starch with oxygen was realized under mild reaction conditions.•Give a high oxidation degree and 86 wt.% yield of solid oxidized starch.•Control the oxidation reaction occurred only outside of the starch granule.The partial oxidation of starch was achieved in the presence of oxygen with Na4Co(H2O)6V10O28·18H2O (abbreviated as CoV10) as catalyst. The oxidation degree of starch was determined by FT-IR, XRD and SEM measurements, which indicated that the aerobic oxidation of starch was promoted by oxidative catalyst CoV10. The application of CoV10 could give a high oxidation degree (DO) of 1.35 COOH/100 GU and 2.07 CO/100 GU with 86 wt.% yield of solid starch under mild reaction conditions (pH = 6; reaction time, 8 h; temperature, 50 °C; catalyst amount, 8 mg, when 1.5 g starch was used as substrate; atmospheric pressure). Among some vanadium compounds, CoV10 exhibited 4-fold activity higher than orthovanadate due to its coordination effect of cobalt and V10O28. Meanwhile, CoV10 could be recycled for six times with only a slight decrease in activity. Thus, CoV10/O2 is one of the most efficient systems for partial oxidation of starch reported so far.

Effect of Cs content on CsxH5−xPMo10V2O40 properties and oxidative catalytic activity on starch oxidation by H2O2

Co-reporter:Xiaoli Chen, Yue Liu, Hang Wang, Mengjia Yuan, Xiaohong Wang and Yaguang Chen

RSC Advances 2014 vol. 4(Issue 22) pp:11232-11239

Publication Date(Web):10 Jan 2014

DOI:10.1039/C3RA47122E

A series of cesium substituted molybovanadophosphric acids, CsxH5−xPMo10V2O40 (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 and 5.0), were synthesized by controlling the ratio of Cs+ to PMo10V2O405−. These complexes were characterized by ICP-AES, FT-IR, XRD, nitrogen physisorption, SEM and Ho measurement. The surface area and acid strength could be adjusted by changing the molar ratio of Cs to H. The highest surface areas were obtained when x = 5 and the highest acidity when x = 0. The catalytic activity of these compounds was evaluated for the oxidation of starch by H2O2, showing that the Brønsted acidity and surface area might influence the oxidation activity. Among all the prepared catalysts, Cs3H2PMo10V2O40 exhibited the best catalytic performance with a carboxylic content of 0.59 mol per 100 g, which could be attributed to the synergy of its Brønsted acidity and surface area. This solid catalyst could be reused at least 6 times without significant loss of performance.

Fabrication of an inorganic–organic hybrid based on an iron-substituted polyoxotungstate as a peroxidase for colorimetric immunoassays of H2O2 and cancer cells

Co-reporter:Congliang Sun, Xiaoli Chen, Jian Xu, Meijie Wei, Jingjing Wang, Xuguang Mi, Xiaohong Wang, Yin Wu and Yu Liu

Journal of Materials Chemistry A 2013 vol. 1(Issue 15) pp:4699-4705

Publication Date(Web):23 Jan 2013

DOI:10.1039/C3TA01255G

Fabrication of a folate and iron-substituted polyoxometalate [(FeOH2)2SiW10O36] has been achieved through self-assembly of folate and polyoxometalate molecules, which was characterized by IR spectroscopy, and transmission electron microscopy (TEM). This inorganic–organic hybrid has been proven to possess intrinsic peroxidase-like activity in the oxidation of dyes, which can catalyze oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to form a blue color in aqueous solution. The TMB/POM/H2O2 system provides a new approach to detect H2O2 with good sensitivity, wide linear range (from 1.34 × 10−7 to 6.7 × 10−5 mol L−1), low detection limit (1 × 10−7 mol L−1) and fast response towards H2O2 instead of an enzyme biosensor. In addition, this unique hybrid FA–Fe2SiW10 is inexpensive, easily prepared, and very efficient in the colorimetric multiplexed immunoassay of cancer cells.

Acid–base bifunctional HPA nanocatalysts promoting heterogeneous transesterification and esterification reactions

Co-reporter:Qian Zhao, Hang Wang, Hongwei Zheng, Zhong Sun, Wei Shi, Shengtian Wang, Xiaohong Wang and Zijiang Jiang

Catalysis Science & Technology 2013 vol. 3(Issue 9) pp:2204-2209

Publication Date(Web):25 Apr 2013

DOI:10.1039/C3CY20868K

A new catalytic system including acid–base bifunctional heteropolyacids (HPAs) nanocatalyst is presented, for the simultaneous transesterification of oil and esterification of free fatty acids (FFAs), to directly convert low quality feedstocks to biodiesel in a one-pot process.

Effects of Brnsted and Lewis Acidities on Catalytic Activity of Heteropolyacids in Transesterification and Esterification Reactions

Co-reporter:W. Shi;J. Zhao;X. Yuan;S. Wang;X. Wang;M. Huo

Chemical Engineering & Technology 2012 Volume 35( Issue 2) pp:347-352

Publication Date(Web):

DOI:10.1002/ceat.201100206

Abstract

Some salts of H₃PW₁₂O₄₀-M_x/nH_3–xPW₁₂O₄₀ (abbreviated as M_x/nH_3–xPW) were prepared and used as acid catalysts for transesterification and esterification reactions. These catalysts have double acidity properties, i.e., Lewis acidity and Brønsted acidity, that are suitable for the conversion of waste cooking oil into biodiesel. The highest efficiency was 59.2 % and 94.7 % corresponding to transesterification and esterification reactions by Ti_0.6H_0.6PW with moderate Lewis acidity. The relationship between the acidic properties and the catalytic activity is discussed in detail.

Synthesis, crystal structure and antitumor activities of the dimeric silicotungstate containing cobalt: Na5K7[{β-SiCo2W10O36(OH)2(H2O)}2] ·39.5H2O

Co-reporter:Rongxin Tan, Xiaohong Pang, Hui Wang, Shuxin Cui, Yaping Jiang, Cheng Wang, Xiaohong Wang, Wenzhi Song

Inorganic Chemistry Communications 2012 Volume 25() pp:70-73

Publication Date(Web):November 2012

DOI:10.1016/j.inoche.2012.09.007

The dimeric polyoxometalate Na5K7[{β-SiCo2W10O36(OH)2(H2O)}2] ·39.5H2O (1) was synthesized and characterized by elemental analysis, IR spectroscopy and thermal gravimetric analysis. A single-crystal X-ray analysis was carried out on the crystal (1) which crystallizes in the triclinic system, space group p ī, with a = 13.231 Å, b = 20.170 Å, c = 21.513 Å, α = 62.964°, β = 89.866°, γ = 78.325° and Z = 1. The polyanion (1) consists of two {β-SiCo2W10O36(OH)2(H2O)}6− Keggin moieties linked via two OH bridging groups, leading to a dimeric silicotungstate containing four cobalt ions. The experiment of antitumor activities in vitro shows that the title compound (1) exhibits remarkable inhibitory actions on liver cancer cells (SMMC-7721) and ovarian cancer cells (SK-OV-3).The dimeric silicotungstate Na5K7[{β-SiCo2W10O36(OH)2(H2O)}2] ·39.5H2O consists of two {β-SiCo2W10O36(OH)2(H2O)}6− Keggin moieties linked by two μ3-OH, and exhibits remarkable inhibitory actions on liver cancer cells SMMC-7721 and ovary cancer cells SK-OV-3 in vitro.Highlights► A new dimeric silicotungstate Na5K7[{β-SiCo2W10O36(OH)2(H2O)}2]· 39.5H2O (1) has been synthesized. ► The crystal (1) consists of two {β-SiCo2W10O36(OH)2(H2O)}6− Keggin moieties linked by two μ3-OH. ► The result of antitumor activities shows that the compound of Co-containing (1) presents remarkable inhibitory actions on liver cancer cells SMMC-7721 and ovary cancer cells SK-OV-3 in vitro.

Polyoxometalates as peroxidase mimetics and their applications in H2O2 and glucose detection

Co-reporter:Jingjing Wang, Dongxue Han, Xiaohong Wang, Bin Qi, Meisheng Zhao

Biosensors and Bioelectronics 2012 Volume 36(Issue 1) pp:18-21

Publication Date(Web):June–July 2012

DOI:10.1016/j.bios.2012.03.031

Polyoxometalates (H3PW12O40, H4SiW12O40 and H3PMo12O40) have been proven to possess intrinsic peroxidase-like activity for the first time, which can catalyze oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to form a blue color in aqueous solution. Among them, H3PW12O40 (PW12) exhibits higher catalytic activity to TMB than natural enzyme HRP and other two POMs. In addition, H3PW12O40/graphene exhibited higher activity than H3PW12O40 in this catalytic oxidation reaction due to the effect of graphene in promoting the electron transfer between the substrate and catalyst. POMs/H2O2/TMB system provides a simple, accurate approach to colorimetric detection for H2O2 or glucose. The colorimetric method based on POMs showed good response toward H2O2 and glucose detection with a linear range from 1.34×10−7 to 6.7×10−5 mol/L and 1×10−7 to 1×10−4 mol/L, respectively. The results showed that it is a simple, cheap, more convenient, highly selective, sensitive, and easy handling colorimetric assay.Highlights► POMs possess intrinsic peroxidase-like activity and can catalyze oxidation of TMB by H2O2. ► POMs/H2O2/TMB system provides a simple approach to colorimetric detection of H2O2 and glucose. ► PW12, as a mimic peroxidase, shows some advantages over natural enzymes. ► PW12 has even higher catalytic activity to TMB than natural enzyme HRP. ► PW12/graphene could facilitate the catalytic oxidation of TMB with H2O2 as oxidant.

Assembly of folate-polyoxometalate hybrid spheres for colorimetric immunoassay like oxidase

Co-reporter:Jingjing Wang, Xuguang Mi, Hongyu Guan, Xiaohong Wang and Yin Wu

Chemical Communications 2011 vol. 47(Issue 10) pp:2940-2942

Publication Date(Web):24 Jan 2011

DOI:10.1039/C0CC04850J

Folate-functionalized polyoxometalate nanoparticles have unique oxidase-like activity, which can facilitate the fast oxidation of organic dyes without using any oxidizing agents or peroxidases especially at neutral pH conditions. This nanoparticle could be used as an agent in colorimetric multiplexed immunoassays.

One pot production of 5-hydroxymethylfurfural with high yield from cellulose by a Brønsted–Lewis–surfactant-combined heteropolyacid catalyst

Co-reporter:Shun Zhao, Mingxing Cheng, Junzi Li, Juan Tian and Xiaohong Wang

Chemical Communications 2011 vol. 47(Issue 7) pp:2176-2178

Publication Date(Web):04 Jan 2011

DOI:10.1039/C0CC04444J

A Brønsted–Lewis–surfactant-combined heteropolyacid (HPA) Cr[(DS)H2PW12O40]3 has been synthesized, and is used as a heterogeneous catalyst for the conversion of cellulose to 5-hydroxymethylfurfural in one pot within 2 h at 150 °C with 77.1% conversion and 52.7% yield. This micellar HPA catalyst shows stability and can be recycled by simple separation process.

Removal of organic dye by air and macroporous ZnO/MoO3/SiO2 hybrid under room conditions

Co-reporter:Mengjia Yuan, Shengtian Wang, Xiaohong Wang, Lingling Zhao, Tianhong Hao

Applied Surface Science 2011 Volume 257(Issue 18) pp:7913-7919

Publication Date(Web):1 July 2011

DOI:10.1016/j.apsusc.2011.03.044

Abstract

A new macroporous ZnO/MoO₃/SiO₂ hybrid was synthesized by a method involving sol–gel technology and biomimetic synthesis. It was characterized by Elemental analysis, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectrum (XPS) and scanning electron microscopy (SEM). Chemical degradation of 0.3 g/L Safranin T (ST) by air oxidation over macroporous ZnO/MoO₃/SiO₂ hybrid was studied. It was found that the decolorization efficiency and the chemical oxygen demand (COD) removal of ST reached above 95.3% and 93.2%, respectively, within 25 min at room temperature and atmospheric pressure. And the organic pollutant was mineralized to simple inorganic species such as HCO₃⁻, Cl⁻ and NO₃⁻, while the total organic carbon (TOC) decreased 95.4%. The structure and morphology of the catalyst were still stable after six cycling runs and the leaching test showed negligible leaching effect.

Degradation of phenol accumulated in a micellar molybdovanadophosphate nanoreactor by air at ambient temperature and atmospheric pressure

Co-reporter:Shun Zhao, Congliang Sun, Lei Wang, Xiaobin Xu and Xiaohong Wang

Dalton Transactions 2010 vol. 39(Issue 21) pp:5087-5090

Publication Date(Web):29 Apr 2010

DOI:10.1039/C000860E

A novel route to facilitate the degradation of phenol is reported. This new approach is based on a micellar polyoxometalate (POM) catalytic system. The micellar POM catalyst could promote phenol molecules’ degradation into a simple inorganic compound such as CO2 using only air as an oxidant under room conditions. The results of the recycling experiment suggests that the micellar POMs may be used as a potential catalyst for the degradation of phenol in wastewater.

Hydrolysis of cellulose by the heteropoly acid H3PW12O40

Co-reporter:Juan Tian;Jianghua Wang;Shun Zhao;Caiyun Jiang;Xia Zhang;Xiaohong Wang

Cellulose 2010 Volume 17( Issue 3) pp:587-594

Publication Date(Web):2010 June

DOI:10.1007/s10570-009-9391-0

The potential of heteropoly acid H3PW12O40 to catalyze the hydrolysis of cellulose to glucose under hydrothermal conditions was explored. This technology could contribute to sustainable societies in the future by using cellulose biomass. A study to optimize the reaction conditions, such as the amount of catalyst, reaction time, temperature, and the amount of cellulose used, was performed. A remarkably high yield of glucose (50.5%) and selectivity higher than 90% at 453 K for 2 h with a mass ratio of cellulose to H3PW12O40 of 0.42 were achieved. This was attributed to the high hydrothermal stability and the excellent catalytic properties, such as the strong Brønsted acid sites. This homogeneous catalyst can be recycled for reuse by extraction with diethyl ether. The results illustrate that H3PW12O40 is an environmentally benign acid catalyst for the hydrolysis of cellulose.

Synthesis and biological evaluation of cyclopenten-1-one Mannich base oxovanadium compound

Co-reporter:Juan Tian;Dongliu Li;Fengying Zhai;Xiaohong Wang;Rui Li

Medicinal Chemistry Research 2010 Volume 19( Issue 9) pp:1162-1173

Publication Date(Web):2010 December

DOI:10.1007/s00044-009-9260-2

2-Hydroxy-3-methyl-2-cyclopenten-1-one Mannich base oxovanadium compound (CPD-VO) was synthesized. The human cancer cell lines SMMC-7721 (liver cancer) and SK-OV-3 (ovary cancer) were tested for their viability by MTT in vitro, which showed that CPD-VO exhibited a remarkable activity against the two cell lines, with IC50 values <0.1 8 and <0.23 μg/ml, respectively. And clonogenic assays showed that CPD-VO at 6.250 μg/ml inhibited colony formation of SMMC-7721 cells by 99.10%. Also, CPD-VO suppressed tumor growth of Hep-A-22 (mouse liver cancer) in mice in vivo. Moreover, the interaction of CPD-VO with λ-DNA was investigated using UV–vis spectroscopy and viscosity. The results showed that CPD-VO was intercalated into the double-helix of λ-DNA. In flow cytometry analysis, the ratio of apoptotic cells was up to 8.15% after treatment with CPD-VO at 2.34 μg/ml after 30 min, suggesting that the antitumoral activity of CPD-VO came from activation of the apoptotic pathway. CPD-VO is a promising antitumoral agent.

Heteropolyacid Nanoreactor with Double Acid Sites as a Highly Efficient and Reusable Catalyst for the Transesterification of Waste Cooking Oil

Co-reporter:Xia Zhang, Jing Li, Yang Chen, Jianghua Wang, Laughlin Feng, Xiaohong Wang and Fenghua Cao

Energy & Fuels 2009 Volume 23(Issue 9) pp:4640-4646

Publication Date(Web):July 27, 2009

DOI:10.1021/ef900396a

A solid zirconiumdodecatungstophosphate Zr0.7H0.2PW12O40 (abbreviated as ZrHPW) with nanotube structure has been synthesized using natural cellulose fiber as a template. The structure and morphology were characterized to show that the primary Keggin structure remained intact in a nanotube with large surface area (256 m2/g). On the basis of the research of acidity, ZrHPW exhibited higher acid strength, both Brønsted acidity and Lewis acidity in one to show higher efficiency, and reusable catalytic activity in biodiesel production from low-quality feedstocks. A synergistic effect results from the channels in the nanotube and doubly catalytic sites to provide an efficient approach to acidic sites for reactants, as well as enough space for subsequent recycling.

Fabrication of Cs2.5H0.5PW12O40 three-dimensional ordered film by colloidal crystal template

Co-reporter:Fang Chai, Dongliu Li, Hongbo Wu, Chunli Zhang, Xiaohong Wang

Journal of Solid State Chemistry 2009 Volume 182(Issue 7) pp:1661-1665

Publication Date(Web):July 2009

DOI:10.1016/j.jssc.2009.03.035

A three-dimensional ordered polyoxometalate periodic film was synthesized using dodecatungstophosphoric acid (H3PW12O40) and Cs2CO3 as precursors and colloidal crystals as templates by an inverse opal method. The samples were characterized by elemental analysis, XRD, IR spectra, UV–Vis diffuse reflectance spectra (DR–UV–Vis) and SEM techniques. This arrayed film constructed by pure cesium salt of dodecatungstophosphoric acid Cs2.5H0.5PW12O40 nanoparticles shows well-defined lamellar array with inverse opal structure, which exhibits a well-defined photonic band gap.A three-dimensional ordered Cs2.5H0.5PW12O40 periodic film was synthesized by an inverse opal method using H3PW12O40 and Cs2CO3 as precursors via nanocasting route and colloidal crystal as template (all scale bars are 1 μm).

Three-dimensional films of photoluminescent polyoxometalates fabricated by a colloidal crystal template

Co-reporter:Fang Chai, Dongliu Li, Xia Zhang, Xiaohong Wang

Thin Solid Films 2009 Volume 518(Issue 1) pp:154-159

Publication Date(Web):2 November 2009

DOI:10.1016/j.tsf.2009.06.047

Three-dimensional ordered thin films based on 12-phosphotungstic acid (PW12O40/SiO2) and lanthanide-substituted phosphotungstate (Eu(PW11O39)2/SiO2, Gd(PW11O39)2/SiO2 and Eu(P2W17O61)2/SiO2) were constructed by an inverse opal method, using polystyrene colloidal crystal as a template. The samples were characterized by elemental analysis, XRD, IR spectra, UV–vis diffuse reflectance spectra (DR-UV–Vis) and SEM techniques. These thin films show well-defined lamellar array with inverse opal structure, and lanthanide polyoxometalate thin films exhibit photoluminescent properties.

Zn1.2H0.6PW12O40 Nanotubes with Double Acid Sites as Heterogeneous Catalysts for the Production of Biodiesel from Waste Cooking Oil

Co-reporter:Jing Li;Xiaohong Wang Dr.;Weimin Zhu;Fenghua Cao

ChemSusChem 2009 Volume 2( Issue 2) pp:177-183

Publication Date(Web):

DOI:10.1002/cssc.200800208

Degradation of dye on polyoxotungstate nanotube under molecular oxygen

Co-reporter:Fang Chai, Lijuan Wang, Linlin Xu, Xiaohong Wang, Jiguo Huang

Dyes and Pigments 2008 Volume 76(Issue 1) pp:113-117

Publication Date(Web):2008

DOI:10.1016/j.dyepig.2006.08.025

A facile process to prepare polyoxometalate Zn1.5[PW12O40] nanotube is presented. The structure and morphology of this nanotube were characterized using IR, elemental analyses, X-ray powder diffraction, 31P MAS NMR and transmission electron microscopy. This nanotube material has a self-supporting tube structure that can be used as a heterogeneous catalyst for the degradation of safranine T (ST) using molecular oxygen (air) as oxidant and can be easily separated from the aqueous phase, thus enabling it to be used several times.

Synthesis and characterization of polyoxometalates loaded starch nanocomplex and its antitumoral activity

Co-reporter:Fengying Zhai, Dongliu Li, Chunli Zhang, Xiaohong Wang, Rui Li

European Journal of Medicinal Chemistry 2008 Volume 43(Issue 9) pp:1911-1917

Publication Date(Web):September 2008

DOI:10.1016/j.ejmech.2007.11.032

According to a water-in-oil emulsion technique using POCl3 as a cross-linking agent, starch nanoparticles have been prepared. Using this starch nanoparticles, loaded polyoxometalates (POMs) α-K8H6 [Si2W18Ti6O77] (Si2W18Ti6) have been prepared and structurally characterized by elemental analyses, IR spectroscopy and NMR spectroscopy. The result shows that the Si2W18Ti6 molecule retains its parent structure after encapsulated by starch nanoparticles and Si2W18Ti6 incorporates into starch matrix to form the nanoparticles. This new complex exhibits higher stability, antitumoral activity and can extend the survival days of the mice with tumor owing to the encapsulation by starch nanoparticles. The Si2W18Ti6 has tested negative for mutagenicity in the standard Ames assay with TA97, TA98, TA100 and TA102, indicating that Si2W18Ti6 has no mutagenic effect in the microsome suspension assay.Using starch nanoparticles, by a water-in-oil emulsion technique, loading polyoxometalates (POMs) a-K8H6 [Si2W18Ti6O77] (Si2W18Ti6) have been prepared. This new complex exhibited higher stability, antitumoral activity and extending the survival days of the mice with tumor than its parent owing to the encapsulation by starch nanoparticles.

Synthesis and structure of dititanium-containing 10-tungstogermanate [{γ-GeTi2W10O36(OH)2}2(μ-O)2]8−

Co-reporter:Rongxin Tan, Dongliu Li, Hongbo Wu, Chunli Zhang, Xiaohong Wang

Inorganic Chemistry Communications 2008 Volume 11(Issue 8) pp:835-836

Publication Date(Web):August 2008

DOI:10.1016/j.inoche.2008.04.012

Dititanium-substituted dimeric tungstogermanate K8[{γ-GeTi2W10O36(OH)2}2(μ-O)2] · 32H2O (1) has been prepared and characterized by elemental analysis, IR spectroscopy and 183W NMR spectroscopy. Single-crystal X-ray analysis has been carried out on K8[{γ-GeTi2W10O36(OH)2}2(μ-O)2] · 32H2O which polyanion comprises two (γ-GeTi2W10O36) Keggin moieties linked by oxygen atoms, and leads to a sandwich-type structure with C2v symmetry.Compound 1 [{γ-GeTi2W10O36(OH)2}2(μ-O)2]8− exhibits a dimeric structure composed of two [γ-GeTi2W10O38]4− units which are linked by two Ti–O–Ti bonds.

Transesterification of Vegetable Oil to Biodiesel using a Heteropolyacid Solid Catalyst

Co-reporter:Fang Chai;Fenghua Cao;Fengying Zhai;Yang Chen;Xiaohong Wang;Zhongmin Su

Advanced Synthesis & Catalysis 2007 Volume 349(Issue 7) pp:

Publication Date(Web):18 MAY 2007

DOI:10.1002/adsc.200600419

A clean, facile, and ecologically friendly method for the production of biodiesel has been developed. A solid acid, namely the heteropolyacid (HPA) Cs_2.5H_0.5PW₁₂O₄₀, has been used as a heterogeneous catalyst for the production of biodiesel from Eruca sativa Gars. oils (ESG oil) with methanol at a certain temperature. A study for optimizing the reaction conditions such as the reaction time, temperature, the oil to methanol ratio, the amount of catalyst, and the usage times of the catalyst, has been performed. The Cs_2.5H_0.5PW₁₂O₄₀ heterogeneous acid catalyst shows almost the same activity under the optimized reaction conditions as compared to a conventional homogeneous catalyst such as sodium hydroxide or sulfuric acid, and can easily be separated from the products and can be used for several more runs. The most important features of this catalyst are that the catalytic activity is not effected by the content of free fatty acids and content of water in the vegetable oil and that the esterification can occur at a lower temperature (room temperature) and be finished within a shorter time. The results illustrate that the Cs_2.5H_0.5PW₁₂O₄₀ is an excellent, water-tolerant and environmentally benign solid acid catalyst for the production of biodiesel. The fuel properties of ESG biodiesel were found to be in agreement with the ASTM standard.

W doped vanadium oxide nanotubes: Synthesis and characterization

Co-reporter:Feng Li, Xiaohong Wang, Changlu Shao, Rongxin Tan, Yichun Liu

Materials Letters 2007 Volume 61(Issue 6) pp:1328-1332

Publication Date(Web):March 2007

DOI:10.1016/j.matlet.2006.07.065

Dendritic and tubular tungsten oxide by surface sol–gel mineralisation of cellulosic substance

Co-reporter:Fang Chai, Rongxin Tan, Fenghua Cao, Fengying Zhai, Xiaohong Wang, Changlu Shao, Yichun Liu

Materials Letters 2007 Volume 61(Issue 18) pp:3939-3941

Publication Date(Web):July 2007

DOI:10.1016/j.matlet.2006.12.087

Dendritic and tubular-like tungsten oxide nanostructures have been prepared by a one-pot approach using a natural cellulosic substance as template at different pH conditions. Analysis by X-ray diffraction and electron microscopy revealed tungsten oxide Na2W2O7 nanostructures having different morphologies according to the pH of the reaction, that is at pH = 3, the morphology of tungsten oxide is dendritic structure; at pH 6 prepared tungsten oxide has tubular structure.

New liposome-encapsulated-polyoxometalates: synthesis and antitumoral activity

Co-reporter:Xiaohong Wang, Feng Li, Shuxia Liu, M.T. Pope

Journal of Inorganic Biochemistry 2005 Volume 99(Issue 2) pp:452-457

Publication Date(Web):February 2005

DOI:10.1016/j.jinorgbio.2004.10.020

Liposome-encapsulated polyoxometalates (abbreviated as LEP): incorporating K6SiW11TiO40 {(SiW11Ti) LEP} have been synthesized and structurally characterized by elemental analysis, and IR, UV–Vis, and NMR spectroscopy. The particle sizes of these complexes ranged from 15 to 60 nm. The polyoxometalate retained the parent structure after encapsulation by the liposome. Based upon in vitro measurements with KB and HeLa cancer cells, the liposome-encapsulation enhances cell-membrane penetration, and the stability and antitumoral activity of the polyoxometalate. The toxicity of the polyoxometalate was reduced when LEPs were employed against HL-60 tumors in vivo.

Conversion of fructose and glucose into 5-hydroxymethylfurfural catalyzed by a solid heteropolyacid salt

Co-reporter:Chunyan Fan, Hongyu Guan, Hang Zhang, Jianghua Wang, Shengtian Wang, Xiaohong Wang

Biomass and Bioenergy (July 2011) Volume 35(Issue 7) pp:2659-2665

Publication Date(Web):July 2011

DOI:10.1016/j.biombioe.2011.03.004

Fast catalytic degradation of organic dye with air and MoO3:Ce nanofibers under room condition

Co-reporter:Wei Li, Shun Zhao, Bin Qi, Yang Du, Xiaohong Wang, Mingxin Huo

Applied Catalysis B: Environmental (9 November 2009) Volume 92(Issues 3–4) pp:333-340

Publication Date(Web):9 November 2009

DOI:10.1016/j.apcatb.2009.08.012

Catalytic wet air oxidation of phenol with air and micellar molybdovanadophosphoric polyoxometalates under room condition

Co-reporter:Shun Zhao, Xiaohong Wang, Mingxin Huo

Applied Catalysis B: Environmental (9 June 2010) Volume 97(Issues 1–2) pp:

Publication Date(Web):9 June 2010

DOI:10.1016/j.apcatb.2010.03.032

Micellar molybdovanadophosphoric polyoxometalate (POM) catalysts [(CnH2n+1)N(CH3)3]3+xPVxMo12−xO40 (x = 1, 2, 3; n = 8, 12, 14, 16, 18) were prepared and used for catalytic wet air oxidation (CWAO) of phenol. X-ray photoelectron spectrum (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) were used to characterize the resulting samples. The best catalytic activity was obtained over (C16TA)6PV3Mo9O40, which showed 95.3% degradation efficiency, 98.5% COD removal and 93.0% TOC reduction with air under room condition toward complete degradation product CO2 within 90 min. The leaching test showed that the POM micellar catalysts have an excellent stability and can be used as heterogeneous catalysts for about six times.

Heteropolyacids embedded in a lipid bilayer covalently bonded to graphene oxide for the facile one-pot conversion of glycerol to lactic acid

Co-reporter:Meilin Tao, Ningyue Sun, Yiming Li, Tong Tong, Marika Wielicako, Shengtian Wang and Xiaohong Wang

Journal of Materials Chemistry A 2017 - vol. 5(Issue 18) pp:NaN8333-8333

Publication Date(Web):2017/03/08

DOI:10.1039/C7TA01334E

A new two-step strategy for the functionalization of graphene oxide (GO) with heteropolyacids (HPAs) and the catalytic activity of the so-obtained materials in the conversion of glycerol to lactic acid (LA) are reported. Covalent bonding of a a-NH–(CH2)2–NH2+–CH2(CH2)8CH3 lipid-like bilayer to the GO surface is followed by embedding of HPAs to give HPMo@lipid(n)/GO hybrid materials, where n represents the length of the diamine carbon chain (n = 2, 4, 6, 8, and 10). The HPAs are tightly surrounded by the lipid bilayer through electrostatic interactions with the protonated amine groups and are highly resistant to environmental changes and leaching from the GO. The hydrophilicity of HPAs and GO and the hydrophobic properties of the lipid bilayer can be easily controlled by changing the length of the alkyl chain, and the redox potential varies as the distance between HPAs and GO varies. The materials show excellent catalytic activity in glycerol cascade conversion to LA, with HPMo@lipid(4)/GO achieving the highest reported efficiency to date, with 90% yield at 97% conversion under mild conditions (1 M glycerol, 60 °C, 3.5 h, and 10 bar O2). Such high efficiency is attributed to the combination of suitable redox potentials, balanced hydrophilic and hydrophobic properties, and the capillary-like reactor formed by the wall of the lipid bilayer, which enhances the adsorption of O2 and glycerol around catalytic active sites. HPMo@lipid(4)/GO functions in the absence of an organic solvent and base, with a high concentration of glycerol (9.2 wt%) and in the presence of methanol and other impurities from biodiesel production, with crude glycerol giving almost 87% yield. No structural changes or leaching of HPAs from GO occurs during the reaction or with recycling up to fifteen times.

A heteropoly acid ionic crystal containing Cr as an active catalyst for dehydration of monosaccharides to produce 5-HMF in water

Co-reporter:Xiaohu Yi, Irina Delidovich, Zhong Sun, Shengtian Wang, Xiaohong Wang and Regina Palkovits

Catalysis Science & Technology (2011-Present) 2015 - vol. 5(Issue 4) pp:NaN2502-2502

Publication Date(Web):2015/02/17

DOI:10.1039/C4CY01555J

Cs2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40], a chromium-based heteropoly acid (HPA) ionic crystal, was demonstrated to be an active heterogeneous catalyst for production of 5-hydroxymethylfurfural (HMF) from fructose or glucose. The dependencies of catalytic activity on reaction parameters such as solvent, temperature and reaction time were investigated and the reaction conditions were optimized. Based on fructose, the yield of HMF reaches 86% and 56% when using DMSO and water as solvents, respectively. Starting from glucose, a yield of HMF up to 48% can be achieved for both aqueous and DMSO media. The catalyst was successfully recycled 5 times.

One pot production of 5-hydroxymethylfurfural with high yield from cellulose by a Brønsted–Lewis–surfactant-combined heteropolyacid catalyst

Co-reporter:Shun Zhao, Mingxing Cheng, Junzi Li, Juan Tian and Xiaohong Wang

Chemical Communications 2011 - vol. 47(Issue 7) pp:NaN2178-2178

Publication Date(Web):2011/01/04

DOI:10.1039/C0CC04444J

A Brønsted–Lewis–surfactant-combined heteropolyacid (HPA) Cr[(DS)H2PW12O40]3 has been synthesized, and is used as a heterogeneous catalyst for the conversion of cellulose to 5-hydroxymethylfurfural in one pot within 2 h at 150 °C with 77.1% conversion and 52.7% yield. This micellar HPA catalyst shows stability and can be recycled by simple separation process.

Assembly of folate-polyoxometalate hybrid spheres for colorimetric immunoassay like oxidase

Co-reporter:Jingjing Wang, Xuguang Mi, Hongyu Guan, Xiaohong Wang and Yin Wu

Chemical Communications 2011 - vol. 47(Issue 10) pp:NaN2942-2942

Publication Date(Web):2011/01/24

DOI:10.1039/C0CC04850J

Folate-functionalized polyoxometalate nanoparticles have unique oxidase-like activity, which can facilitate the fast oxidation of organic dyes without using any oxidizing agents or peroxidases especially at neutral pH conditions. This nanoparticle could be used as an agent in colorimetric multiplexed immunoassays.

Fabrication of an inorganic–organic hybrid based on an iron-substituted polyoxotungstate as a peroxidase for colorimetric immunoassays of H2O2 and cancer cells

Co-reporter:Congliang Sun, Xiaoli Chen, Jian Xu, Meijie Wei, Jingjing Wang, Xuguang Mi, Xiaohong Wang, Yin Wu and Yu Liu

Journal of Materials Chemistry A 2013 - vol. 1(Issue 15) pp:NaN4705-4705

Publication Date(Web):2013/01/23

DOI:10.1039/C3TA01255G

Fabrication of a folate and iron-substituted polyoxometalate [(FeOH2)2SiW10O36] has been achieved through self-assembly of folate and polyoxometalate molecules, which was characterized by IR spectroscopy, and transmission electron microscopy (TEM). This inorganic–organic hybrid has been proven to possess intrinsic peroxidase-like activity in the oxidation of dyes, which can catalyze oxidation of the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 to form a blue color in aqueous solution. The TMB/POM/H2O2 system provides a new approach to detect H2O2 with good sensitivity, wide linear range (from 1.34 × 10−7 to 6.7 × 10−5 mol L−1), low detection limit (1 × 10−7 mol L−1) and fast response towards H2O2 instead of an enzyme biosensor. In addition, this unique hybrid FA–Fe2SiW10 is inexpensive, easily prepared, and very efficient in the colorimetric multiplexed immunoassay of cancer cells.

Degradation of phenol accumulated in a micellar molybdovanadophosphate nanoreactor by air at ambient temperature and atmospheric pressure

Co-reporter:Shun Zhao, Congliang Sun, Lei Wang, Xiaobin Xu and Xiaohong Wang

Dalton Transactions 2010 - vol. 39(Issue 21) pp:NaN5090-5090

Publication Date(Web):2010/04/29

DOI:10.1039/C000860E

A novel route to facilitate the degradation of phenol is reported. This new approach is based on a micellar polyoxometalate (POM) catalytic system. The micellar POM catalyst could promote phenol molecules’ degradation into a simple inorganic compound such as CO2 using only air as an oxidant under room conditions. The results of the recycling experiment suggests that the micellar POMs may be used as a potential catalyst for the degradation of phenol in wastewater.

Lewis-acid-promoted catalytic cascade conversion of glycerol to lactic acid by polyoxometalates

Co-reporter:Meilin Tao, Dan Zhang, Xi Deng, Xiangyu Li, Junyou Shi and Xiaohong Wang

Chemical Communications 2016 - vol. 52(Issue 16) pp:NaN3335-3335

Publication Date(Web):2016/01/19

DOI:10.1039/C5CC10262F

The polyoxometalates AlPMo12O40 and CrPMo12O40 show high activity and reusablility for cascade conversion of glycerol directly to lactic acid under mild conditions without the addition of base, and can be reused more than 12 times with 90.5% selectivity at 93.7% conversion. AlPMo12O40 is tolerant to crude glycerol from biodiesel production.

Acid–base bifunctional HPA nanocatalysts promoting heterogeneous transesterification and esterification reactions

Co-reporter:Qian Zhao, Hang Wang, Hongwei Zheng, Zhong Sun, Wei Shi, Shengtian Wang, Xiaohong Wang and Zijiang Jiang

Catalysis Science & Technology (2011-Present) 2013 - vol. 3(Issue 9) pp:NaN2209-2209

Publication Date(Web):2013/04/25

DOI:10.1039/C3CY20868K

A new catalytic system including acid–base bifunctional heteropolyacids (HPAs) nanocatalyst is presented, for the simultaneous transesterification of oil and esterification of free fatty acids (FFAs), to directly convert low quality feedstocks to biodiesel in a one-pot process.

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Abstract

Abstract