Preparation and Characterization of Hydrogen Molybdenum Bronzes, HxMoO3

Abstract

Hydrogen molybdenum bronzes, HxMoO3, of Type-I (x=0.21), Type-III (x=1.55), and Type-IV (x=1.90) were prepared by the Glemser’s method. Type-II (x=0.91) was obtained from Type-III by standing in air for 120 days. The bronzes with low hydrogen contents were stable, but those with high contents were not so stable. All these bronzes have been studied by X-ray diffraction, IR spectroscopy, and TG-DTA. Bronzes with high hydrogen contents were changed upon heating in air, successively, to those with low hydrogen contents by the evolution of H2.

Preparation of Hydrated Potassium Molybdenum Bronzes and Their Thermal Decomposition

“…TG results in the air atmosphere shows the gradual weight decreases of 0.4% from 360 to 455 K and an increase of 0.7% upto 610 K. In the case of nitrogen atmosphere, the weight also decreases gradually by 0.6% from 382 to 636 K. The behavior of the weight decreases in both cases is very similar to the result of the Type I hydrogen bronze (14). Therefore, it is assumed that these gradual weight decreases result from the removal of protons.…”

“…(11), when a small amount of protons was introduced into the hydrated sodium bronzes, a small band also appeared at around 1005 cm\. Type I hydrogen bronze shows the typical IR band at around 1005 cm\, which appeared when protons were introduced into the intrasite between oxygens of MoO octahedra (14). This suggests that the proton is introduced into the intrasite of hydrated potassium bronzes as in the case of Type I hydrogen bronze.…”

Hydrothermal Synthesis of the Blue Potassium Molybdenum Bronze, K0.28MoO3

“…A 1.296-g amount of H V MoO (ca. 0.009 mol), which can be prepared from MoO at ambient temperature following the previous procedure (19), was suspended in 30 ml of 0.9 M KCl solution in a Te#on-lined autoclave with a volume of 60 ml stirring on a magnetic stirrer, and then heated in a forced convection oven for certain speci"ed times at 431 K and autogeneous pressure. Di!erent from route I, all the loading operations here were done in a nitrogen-"lled glove box.…”

Micro and nanostructures of molybdenum trioxide (VI)

“…These lead to the crystal grows by preferentially exposing the [010] face, thus resulting in elongated stab-like crystals. This characteristic yields directly nanostructures of MoO 3 [8,9].…”