Three Bi-doped vanadyl pyrophosphate catalysts were prepared via dihydrate route (VPD method), which consisted of different preparation methods including mechanosynthesis, mechanochemical treatment, and the conventional reflux method. The catalysts produced by the above three methods were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and temperature programmed re...

Introduction Nitrogen oxides (NOx) cause the photochemical smog, acid rain, ozone depletion and greenhouse effect. Therefore, a great deal of studies has been performed to reduce NOx by using various catalytic systems such as selective catalytic reduction (SCR) or NOx storagereduction catalyst. Recently, N2O, whose greenhouse effect is 310 times larger than CO2, has been issued due to the new r...

X-ray diffraction, Raman spectroscopy, 3’P MAS-NMR and spin-echo NMR indicated that model vanadium phosphorus oxide (VPO) precursors and catalysts contained various minor phases depending oxboth the synthetic approach and P/V ratios used. Raman spectroscopy revealed the presence of a number of micro-crystalline and amorphous V(W) and V(V) phases not evident by XRD. The presence of VOPO, phases ...

Early-transition-metal hydrogenation catalysts have received less attention than comparable late-transition-metal systems, particularly since the discovery of Wilkinson s catalyst. This emphasis on late-transition-metal systems has been largely driven by practical concerns including functional-group tolerance and ease of handling. Further examination of early-transition-metal systems is particu...

The possibility of application of 4-nitrocatechol (4-NC) - tetrazolium salt - organic solventsystems for liquid-liquid extraction-spectrophotometric vanadium (IV and V) speciation wasstudied. Six commercially available tetrazolium salts (2,3,5-triphenyltetrazolium chloride (TTC),3-(2-naphtyl)-2,5-diphenyltetrazolium chloride (Tetrazolium Violet, TV); 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyltetra...

Vanadium is the 22 most abundant element in the earth’s crust with an average concentration of 100 ppm. It exists in oxidation states ranging from 2to 5+ with 3+, 4+, and 5+ being the most common oxidation states. Vanadium is primarily used in the production of rust-resistant, spring, and high-speed tool steels; vanadium pentoxide is used in ceramics. Vanadium is released to the environment by ...