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.

Synthesis of silica@C-dots/phosphotungstates core-shell microsphere for effective oxidative-adsorptive desulfurization of dibenzothiophene with less oxidant

Abstract: A core-shell microsphere catalyst with a solid silica core and a mesoporous shell made up of quaternary ammonium phosphotungstate and carbon dots (C-dots) was successfully synthesized for the oxidative-adsorptive desulfurization (OADS) of dibenzothiophene (DBT) in fuel oil. The phosphotungstic acid used for the synthesis of the catalyst was calcined to enhance its activity. XRD, FT-IR and catalytic test showed that the defective Keggin anion [PW12O38]3− formed under proper calcination conditions could explain the activity enhancement. EPR measurement indicated that hydroxyl radicals were generated from H2O2 by the interaction with C-dots, which proved C-dots to be an efficient cocatalyst in the system. The synergetic effect of [PW12O38]3− and C-dots in the synthesized catalyst remarkably improve the utilization efficiency of H2O2. When the loading amount of phosphotungstate and C-dots were optimized to 25% and 0.45%, the OADS system showed best desulfurization capacity under 50 °C. A high OADS efficiency of 98.08% could still be achieved even when the ratio of n(H2O2)/n(DBT) was reduced to 1.75. The existence of dibenzothiophene sulfoxide (DBTO) in the acetonitrile eluent of spent catalyst was confirmed by LC–MS spectra. The characterization results indicated that part of the DBT was oxidized to its corresponding sulfoxide which need less oxidant than sulfone. Both of the oxidation products could be eliminated from oil phase by adsorption on the catalyst.

PtRu catalysts supported on heteropolyacid and chitosan functionalized carbon nanotubes for methanol oxidation reaction of fuel cells.

Abstract: A simple self-assembly approach has been developed to functionalize carbon nanotubes (CNTs) with chitosan (CS) and heteropolyacids (HPAs) of phosphomolybdic acid (H3PMo12O40, HPMo) and phosphotungstic acid (H3PW12O40, HPW). The non-covalent functionalization method, which introduces homogenous surface functional groups with no detrimental effect on graphene structures of CNTs, can be carried out at room temperature without the use of corrosive acids. The PtRu nanoparticles supported on HPAs-CS-CNTs have a uniform distribution and much smaller size as compared to those of the PtRu nanoparticles supported on conventional acid treated CNTs (PtRu/AO-CNTs). The onset and peak potentials for COadoxidation on PtRu/HPAs-CS-CNTs catalysts are more negative than those on PtRu/AO-CNTs, indicating that HPAs facilitate the electro-oxidation of CO. The PtRu/HPMo-CS-CNTs catalyst has a higher electrocatalytic activity for methanol oxidation and higher tolerance toward CO poisoning than PtRu/HPW-CS-CNTs. The better electrocatalytic enhancement of HPMo on the PtRu/HPAs-CS-CNTs catalyst is most likely related to the fact that molybdenum-containing HPAs such as HPMo have more labile terminal oxygen to provide additional active oxygen sites while accelerating the CO and methanol oxidation in a similar way to that of Ru in the PtRu binary alloy system.

Structure of the Crystals of 12-Phosphotungstic Acid

Abstract: IN a recent communication1, the structure of the molecule of 12-phosphotungstic acid was described. The formula of the acid was found to be H3PW12O40.nH2O. This structure was worked out from powder photographs of the partially dehydrated acid, containing 6 or 7 molecules of water per molecule of acid, which is obtained by drying the more highly hydrated crystals to constant weight over P2O5 in vacuo.