Showing papers on "Phosphotungstic acid published in 2020"
TL;DR: A facile approach was introduced for the local synthesis of Au nanoparticledecorated polyoxometalate/Zeolitic Imidazolate Framework-8 nanostructure (denoted ZIF-8@PTA@AuNP) to prepare highly active adsorbent and photocatalyst as mentioned in this paper.
61 citations
TL;DR: In this paper, a 3D printing method was employed to prepare 3D printed spheres (3D-PSs), followed by carbonization to form 3D-CSs.
55 citations
TL;DR: In this paper, a POM-based MOF was synthesized in situ with a carboxyl-functionalized ionic liquid as a bridge to combine the POM and MOF.
52 citations
TL;DR: In this paper, a feasible approach to convert glucose and cellulose to levulinic acid applying phosphotungstic acid as catalyst in deep eutectic solvent was proposed, where a considerable yield of levulinics acid (98.9 %) from glucose was achieved using 30 g/L phosphotuned acid as a catalyst at 468 K for 80 min.
48 citations
TL;DR: In this paper, the electron transfer from Fe atom to PTA cluster and strong covalent metal support interactions (CMSI) between the Fe 3d orbitals and O 2p orbitals of PTA lay the foundation of high stability.
Abstract: Geometric and electronic structures of phosphotungstic acid (PTA) supported single transition metal atom (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir and Pt) catalysts have been systematically investigated by using the first-principles theoretical methods. Possible reaction mechanism for ethylene epoxidation was explored. The most possible anchoring site for the single transition metal atom is the fourfold hollow site on PTA. As the non-noble metal Fe1-PTA system possesses considerable adsorption energies towards both O2 and C2H4, the strong bonding interaction between Fe1 and PTA cluster was analyzed. It is found that the electron transfers from Fe atom to PTA cluster and strong covalent metal-support interactions (CMSI) between the Fe 3d orbitals and O 2p orbitals of PTA lay the foundation of high stability. The proposed catalytic reaction mechanism for ethylene epoxidation on Fe1-PTA single-atom catalyst (SAC) includes three steps: the O2 adsorbs on Fe1-PTA via electron transfer; the first ethylene attacks the adsorbed O2 molecule on Fe1-PTA followed by the formation of C2H4O; finally, the O atom remained on Fe1-PTA reacts with a second ethylene to form the product and accomplish the catalytic cycle. The Fe1-PTA has high selectivity and catalytic activity for ethylene epoxidation via an Eley–Rideal mechanism with low energy barriers. A potentially competitive pathway for the formation of acetaldehyde is not kinetically favorable. These results provide insights for the development of highly efficient heterogeneous SACs for ethylene epoxidation with non-noble metals.
34 citations
TL;DR: In this article, an ultra-high ion-selective Nafion composite membrane modified by phosphotungstic acid (PWA) coupled silica for vanadium redox flow battery (VRB) was constructed and prepared through solution casting.
34 citations
TL;DR: In this article, a nano-sized hierarchical hollow silica spheres (HPW-NH2-HHSS) was successfully prepared and completely characterized and applied to simultaneous oxidation and adsorption of dibenzothiophene (DBT) from model fuel.
33 citations
TL;DR: In this article, a self-crosslinked sulfonated polyether etherketone membrane (C-SPEEK) was synthesized by Friedel-Crafts alkylation at 130°C with chloromethylated SOPE (SPEEK-Cl).
31 citations
TL;DR: In this paper, the performance of tetracycline hydrochloride (TC.HCl) adsorption by MIL-53 (Fe), PTA/MIL-53(Fe) (phosphotungstic acid impregnating via post modification) and four different contents of PTA in PTA@MIL 53 (Fe).
Abstract: The performance of tetracycline hydrochloride (TC.HCl) adsorption by MIL–53 (Fe), PTA/MIL–53 (Fe) (phosphotungstic acid impregnating via post modification) and four different contents of PTA in PTA@MIL–53 (Fe) (phosphotungstic acid encapsulating via one–pot method) were investigated. The results proved that the comparison adsorption capacity of the adsorbent in high concentration of TC.HCl is: PTA(10 wt%)@MIL–53 (Fe) > PTA(16 wt%)@MIL–53 (Fe) > PTA(6 wt%)@MIL–53 (Fe) > PTA(30 wt%)@MIL–53 (Fe) > PTA/MIL–53 (Fe) > MIL–53 (Fe). The maximum adsorption capacity of TC.HCl on to PTA(10 wt%)@MIL–53 (Fe) using Langmuir equation was 1250 mg/g which is extremely high. The isotherm adsorption data were found to fit Langmuir model and the adsorption process was matched by pseudo–second–order kinetics model. The thermodynamic assessments expressed that the process is spontaneous and endothermic. The regeneration experiments by 0.1 M HCl/ethanol (10/90, v/v) as elution agent showed that the adsorption capacity was not changed significantly even after 3 times reusing. PTA (10 wt%)@MIL–53 (Fe) showed a great potential to be a good adsorbent for TC.HCl removal from an aqueous media and also capable of being regenerated.
30 citations
TL;DR: The direct shedding of piperazine rings in the decarboxylation and defluorination process leads to the most efficient degradation of CIP into the small molecules.
29 citations
TL;DR: In this paper, a strategy by using polyoxometalates (POMs) as the ligands is proposed to engineer the surface and electronic properties of Pt/CNT catalysts toward the enhanced hydrogen generation rate and durability.
26 May 2020
TL;DR: A novel solid acid nanocatalyst comprising ammonium and silver co-doped H3PW12O40 and zirconium-based metal–organic frameworks (UiO-66) was synthesized and characterized by Fourier transform infrared spectroscopy, N2 adsorption/desorption, X-ray diffraction, scanning electron microscopy, and ammonia temperature-programmed desorption to obtain optimum reaction conditions.
Abstract: A novel solid acid nanocatalyst (Ag1(NH4)2PW12O40/UiO-66) comprising ammonium and silver co-doped H3PW12O40 and zirconium-based metal–organic frameworks (UiO-66) was synthesized and characterized b...
TL;DR: In this article, 13 amine or quaternary ammonium functionalized polyacrylonitrile fiber (PANF) supported PTA catalysts were designed and prepared, and their catalytic activities were screened by choosing condensation/annulation tandem synthesis of 2,3-dihydroquinazolin-4(1H)-one compound via C-N bond formation between 2-aminobenzamide and p-chlorobenzaldehyde as a model reaction.
TL;DR: In this paper, a long carbon chain modified phosphotungstic acid ionic liquid [C12mim]3PW12O40 (C12PW) is immobilized on graphitic carbon nitride (g-C3N4) to enhance the dispersion properties both in the oil phase and H2O phase.
TL;DR: In this article, Pd/C combined with HPW, a strong Bronsted solid acid promoter, was developed to produce decane under mild conditions through the one-pot HDO of δ-furfurylidenelevulinic acid (FDLA).
TL;DR: In this paper, a mesoporous structure with the retention of the Keggin structure of well-dispersed phosphotungstic acid (HPW) on the Mobil composition of matter-twenty-two (MWW) zeolite was used for desulfurization of gasoline.
Abstract: Catalysts for the desulfurization of gasoline samples were synthesized via the immobilization of well-dispersed phosphotungstic acid (HPW) on Mobil composition of matter-twenty-two (MWW) zeolite. Characterization results indicated that these catalysts possess a mesoporous structure with the retention of the Keggin structure of immobilized HPW. Relevant reaction parameters influencing sulfur removal were systematically investigated, including HPW loading, catalyst dosage, temperature, initial S-concentration, molar ratio of oxidant to sulfide (O/S), volume ratio of MeCN to model oil (Ext./oil), and sulfide species. The 40 wt-% HPW/MWW catalyst exhibited the highest catalytic activity with 99.6% dibenzothiophene sulfur removal from prepared samples. The 40 wt-% HPW/MWW catalyst was recycled four times and could be easily regenerated. Finally, as an exploratory study, straight-run-gasoline and fluid catalytic cracking gasoline were employed to accurately evaluate the desulfurization performance of 40 wt-% HPW/MWW. Our research provides new insights into the development and application of catalysts for desulfurization of gasoline.
TL;DR: In this article, a new TiO2/HPW/CoPz composite photocatalyst was proposed to achieve highly selective oxidation of glucose to gluconic acid and glucaric acid.
TL;DR: The acid doping enhanced proton conductivity of PBI membranes and, after doping, these conducting materials maintained their mechanical properties and thermal stability for their application as proton exchange membrane fuel cells, capable of operating at intermediate or high temperatures.
Abstract: The use of phosphoric acid doped polybenzimidazole (PBI) membranes for fuel cell applications has been extensively studied in the past decades In this article, we present a systematic study of the physicochemical properties and proton conductivity of PBI membranes doped with the commonly used phosphoric acid at different concentrations (01, 1, and 14 M), and with other alternative acids such as phytic acid (0075 M) and phosphotungstic acid (HPW, 01 M) The use of these three acids was reflected in the formation of channels in the polymeric network as observed by cross-section SEM images The acid doping enhanced proton conductivity of PBI membranes and, after doping, these conducting materials maintained their mechanical properties and thermal stability for their application as proton exchange membrane fuel cells, capable of operating at intermediate or high temperatures Under doping with similar acidic concentrations, membranes with phytic acid displayed a superior conducting behavior when compared to doping with phosphoric acid or phosphotungstic acid
TL;DR: In this paper, triazole COF loaded with HPW was incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to fabricate SPEEK/HPW@COF composite membranes.
TL;DR: In this paper, the performance of the fabricated nanocomposite membranes and the leakage of phosphotungstic acid (HPW) was investigated, and they showed improved dimensional stability, water affinity and physicochemical stability, as well as better proton conductivity and fuel cell performance.
TL;DR: In this article, a series of heterogeneous acid catalysts are synthesized by supporting phosphotungstic acid on bamboo activated carbon and applied in catalyzing esterification for biodiesel production.
Abstract: A series of heterogeneous acid catalysts are synthesized by supporting phosphotungstic acid on bamboo activated carbon and applied in catalyzing esterification for biodiesel production. With the activation of phosphoric acid, the obtained catalyst possesses the total acid density of 2.02 mmol g−1 and developed pore structure with specific surface area of 576 m2 g−1. It exhibits superior performance in catalyzing esterification of oleic acid with the maximum efficiency of 96% and acceptable renewability, where efficiency of 93% could be achieved by the regenerated catalyst. Density functional theory results indicate the activation barrier and reaction energy of the esterification are 19.73 kcal mol-1 and −15.83 kcal mol-1, respectively. This paper provides feasibility of the high value-added utilization of bamboo and basic theoretical data for esterification mechanism over heterogeneous acid catalysts.
TL;DR: In this paper, a multilayer three-dimensional network structure was synthesized with cellulose aerogel as the framework and MOFs as the filler, and the degradation rate of methylene blue at δ = 10 ppm reached 99.8% in 30 min under the conditions of PTA/ZIF-8@CA input amount of 0.6 g·L−1 and pH = 5.8%.
Abstract: A novel PTA/ZIF-8@CA composite material (PTA = phosphotungstic acid; CA = cellulose aerogel) with multilayer three-dimensional network structure was synthesized with cellulose aerogel as the framework and MOFs as the filler. The results showed that the degradation rates of methylene blue at δ = 10 ppm reached 99.8% respectively in 30 min under the conditions of PTA/ZIF-8@CA input amount of 0.6 g·L–1 and pH = 5. The degradation rate of rhodamine B at δ =
TL;DR: In this article, the feasibility of total reducing sugar (TRS) yield through the composition analysis and catalytic biomass hydrolysis was examined for five different biomass feedstocks, namely, miscanthus, sugarcane leaves, switchgrass, sunflower seeds, and bamboo leaves.
TL;DR: In this article, the free energy of adsorption for MP-2 at 298, 308, 318 and 328 K was −15.24, 15.93, −16.63, −17.32 and − 17.99 kJ/mol for MB, respectively.
TL;DR: In this article, the H3PW12O40-doped pyromellitic diimide (PMDI) photocatalysts via thermal transformation using urea phosphotungstate and pyromelli dianhydride as precursors (UPWPI) and calcination of PMDI with UPIPW directly (UPIPW).
Abstract: We prepared the H3PW12O40-doped pyromellitic diimide (PMDI) photocatalysts via thermal transformation using urea phosphotungstate and pyromellitic dianhydride as precursors (UPWPI) and calcination of PMDI with phosphotungstic acid directly (UPIPW). The influences of the strategies on the morphology, light absorption, and visible-light photocatalytic degradation efficiency of H3PW12O40-doped PMDI are systematically investigated by various characterization methods. By comparing the structure of UPWPI and UPIPW, the adoption of urea phosphotungstate as precursors can promote the separation of PMDI into small particles and the inclusion of phosphotungstic acid. Moreover, the visible-light (λ > 420 nm) absorption efficiency of UPWPI is also enhanced compared with that of UPIPW because of the improved photogenerated electron transfer efficiency between PMDI and HPW. With a catalyst dosage of 100 mg and the degradation time of 3 h, the photocatalytic degradation efficiency of imidacloprid on UPWPI was 97.12% and the degradation rate constant was 0.93 h−1.
TL;DR: In this paper, an amperometric sensor of polydiphenylamine (PDPA)/phosphotungstic acid (PTA)/zinc oxide (ZnO) on glassy carbon (GC) nanohybrid composite electrode was fabricated via facile electrochemical deposition method.
Abstract: Amperometric sensor of polydiphenylamine (PDPA)/phosphotungstic acid (PTA)/zinc oxide (ZnO) on glassy carbon (GC) nanohybrid composite electrode (GC/PDPA/PTA/ZnO) fabricated via facile electrochemical deposition method. The structural geometry and surface morphology were recorded by X-ray diffraction spectrometer (XRD) and scanning electron microscopy (SEM). Electro-catalytic properties and performances of nanohybrid composite were recorded by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) methods. PTA-assisted PDPA/ZnO-ME shows linear steady-state response towards glucose with superior sensitivity of 20.30 μA μM−1 cm−2, lowest detection limit 0.1 μM, and rapid response less than 2 s. The improved electro-catalytic performance towards glucose by GC/PDPA/PTA/ZnO is due to the combined existence of diphenoquinone diamine (DPDI2+) and phosphotungstic acid anion which provides a higher electro-catalytic active spots leads to more electron transport pathway for the oxidation of glucose. Interference analyses confirm the prepared nanohybrid sensor is best apt for glucose detection claims its practical biomedical application.
TL;DR: In this paper, the reaction mechanism is not auto-oxidation involving free radicals, instead, the substrate was first activated by one-electron oxidation by H3PW12O40 catalyst and then reacted with O2.
TL;DR: In this article, a bifunctional catalyst for the conversion of methyl palmitate into jet biofuel, loaded on Ni/MCM-41 catalyst enhanced strong acidity to strengthen conversion pathways of hydrocracking and isomerization.
TL;DR: In this article, the effect of microwave irradiation on the catalytic oxidative desulfurization (ODS) of light gasoil fraction has been investigated using core/shell magnetic silica supported with phosphotungstic acid (Ni@SiO2\PWA) nanocomposite catalyst.