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.

Critical Staining of Pancreatic Alpha Granules with Phosphotungstic Acid Hematoxylin

Abstract: Mammalian pancreatic alpha granules were differentially stained with phosphotungstic acid haematoxylin Paraffin sections were dewaxed and hydrated, oxidised 5-40 sec in freshly prepared 03% KMnO4 acidified with 03% (w/v) H2SO4, decolourised in 4% potassium metabisulphite, mordanted 20 min to 2 hr in 4% iron alum, stained in phosphotungstic acid haematoxylin 16-48 hr, rinsed in 95% ethanol until no stain runs from the tissue, dehydrated in absolute ethanol, cleared in xylene, and covered in synthetic resin Advantages of this procedure are: (1) consistent, reproducible staining; (2) applicability to all the common laboratory mammals and man; (3) wide latitude at each stage, permitting its use as a routine method; and (4) superior visualization of alpha granules, due to suppression of background staining and absence of glare For fixation, formalin-acetic or Bouin's solution is recommended

In Situ Formed Phosphoric Acid/Phosphosilicate Nanoclusters in the Exceptional Enhancement of Durability of Polybenzimidazole Membrane Fuel Cells at Elevated High Temperatures

Abstract: Most recently, we developed a phosphotungstic acid impregnated mesoporous silica (PWA-meso-silica) and phosphoric acid doped polybenzimidazole (PA/PBI) composite membrane for use in high temperature fuel cells and achieved exceptional durability under a constant current load of 200 mA cm(-2) at 200 degrees C for over 2700 h. In this work, the fundamental role of PWA-meso-silica in enhancing the stability of the PA/PBI membrane has been investigated. The microstructure, the PA uptake, swelling ratio, mechanical property and conductivity of PA/PBI/PWA-meso-silica composite membranes depend on the loading of PWA-meso-silica. The results indicate that the optimum limit of PWA-meso-silica loading in the PA/PBI membranes is 15 wt%. Detaled analysis indicates that the mesoporous structure of the PWA-meso-silica framework disintegrates, forming phosphosilicate phases within the PBI polymeric matrix during fuel cell operation at 200 degrees C. The in situ formed phosphosilicates can immobilize a significant amount of PA, forming PA/phosphosilicate nanoclusters that possess high proton conductivity (e.g., 7.2 x 10(-2) S cm(-1) at 250 degrees C) and stability and substantially inhibits acid leaching out of themembrane. The substantially reduced acid leaching also alleviates the excess acid in the catalyst layer, reducing the detrimental effect of excess acid on the agglomeration of Pt catalysts especially in the cathode catalyst layer. These phenomena are responsible for the exceptional stability in proton conductivity as well as the significantly reduced agglomeration of Pt nanoparticles in the anode and cathode catalyst layers of PA/PBI/PWA-meso-silica composite membrane fuel cells. (c) 2017 The Electrochemical Society. All rights reserved.