Phosphotungstic acid

About: Phosphotungstic acid is a research topic. Over the lifetime, 1925 publications have been published within this topic receiving 38059 citations. The topic is also known as: Phosphowolframic acid.

Catalytic conversion of cellulose for efficient ethylene glycol production and insights into the reaction pathways

Abstract: As promising and environmentally friendly catalysts, tungsten-containing heteropoly acids combined with supported noble metals were used for one-pot hydrothermal conversion of cellulose into polyols in the presence of pressurized hydrogen. The microcrystalline cellulose was completely converted over a mixed catalyst consisting of a low concentration of phosphotungstic acid (PTA) (0.03 wt%) and Ru/activated carbon (Ru/AC) via an one-pot hydrothermal reaction, with an ethylene glycol (EG) yield of up to 53.1% under optimal conditions. The catalytic activity of the mixed catalyst gradually decreased with increasing reaction runs, which could be mainly ascribed to the aggregation of Ru/AC particles, and to the coverage of the active sites of Ru due to the deposition of organic materials. Cellobiose was used as a model feedstock for a comparative study on the reaction pathways of the conversion of cellulose, and the results revealed that catalytic conversion of cellobiose consisted of at least three important parallel reactions under the present hydrothermal conditions, which were also most likely involved during the catalytic conversion of cellulose for EG production. Effective control of these reactions would be helpful to further maximize the EG yield during the catalytic conversion of cellulose.

H3PW12O40-doped pyromellitic diimide prepared via thermal transformation as an efficient visible-light photocatalyst

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.

Fabrication of amperometric sensor for glucose detection based on phosphotungstic acid–assisted PDPA/ZnO nanohybrid composite

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.