Potential Of Vanadium Research Articles

Charge Transfer Modulation in Vanadium-Doped WS2 /Bi2 O2 Se Heterostructures.

The field of photovoltaics is revolutionized in recent years by the development of two-dimensional (2D) type-II heterostructures. These heterostructures are made up of two different materials with different electronic properties, which allows for the capture of a broader spectrum of solar energy than traditional photovoltaic devices. In this study, the potential of vanadium (V)-doped WS2 is investigated, hereafter labeled V-WS2 , in combination with air-stable Bi2 O2 Se for use in high-performance photovoltaic devices. Various techniques are used to confirm the charge transfer of these heterostructures, including photoluminescence (PL) and Raman spectroscopy, along with Kelvin probe force microscopy (KPFM). The results show that the PL is quenched by 40%, 95%, and 97% for WS2 /Bi2 O2 Se, 0.4 at.% V-WS2 /Bi2 O2 Se, and 2at.% V-WS2 /Bi2 O2 Se, respectively, indicating a superior charge transfer in V-WS2 /Bi2 O2 Se compared to pristine WS2 /Bi2 O2 Se. The exciton binding energies for WS2 /Bi2 O2 Se, 0.4at.% V-WS2 /Bi2 O2 Se and 2 at.% V-WS2 /Bi2 O2 Se heterostructures are estimated to be ≈130, 100, and 80 meV, respectively, which is much lower than that for monolayer WS2 . These findings confirm that by incorporating V-doped WS2 , charge transfer in WS2 /Bi2 O2 Se heterostructures can be tuned, providing a novel light-harvesting technique for the development of the next generation of photovoltaic devices based on V-doped transition metal dichalcogenides (TMDCs)/Bi2 O2 Se.

Potential of Vanadium (V) doped CNT(10, 0) and Manganese (Mn) doped carbon nanocage (C60) as catalysts for oxygen reduction reaction in fuel cells

In this work, possible mechanisms of ORR on V-CNT(10, 0) and Mn2-C60 are investigated. The ORR on V-CNT(10, 0) and Mn2-C60 is processed through two acceptable paths. Results indicated that the V-CNT(10, 0) and Mn2-C60 have great tolerance against the CO poisoning. Results demonstrated that the O2 dissociation of *O2-V-CNT(10, 0) and *O2-Mn2-C60 are occurred difficulty because the reaction barrier energies are 1.48 and 1.22 eV, respectively. Results shown that Mn2-C60 has lower potential than V-CNT(10, 0) to adsorb the CO and so Mn2-C60 has lower CO poisoning than V-CNT(10, 0). Results shown than the V-CNT(10, 0) has lower over potential for ORR than Mn2-C60. The V-CNT(10, 0) and Mn2-C60 catalysts with lower over potential than Palladium catalysts for ORR in fuel cell.

Chemopreventive effect of vanadium in a rodent model of chemical hepatocarcinogenesis: reflections in oxidative DNA damage, energy-dispersive X-ray fluorescence profile and metallothionein expression

In the present study, we investigated the antitumour efficacy of vanadium in a defined rodent model of experimental hepatocarcinogenesis. Hepatic preneoplasia was induced in male Sprague-Dawley rats with a single, necrogenic, intraperitoneal injection of diethylnitrosamine (DEN) (200 mg/kg body weight) followed by promotion with phenobarbital (PB). The levels of modified DNA bases 8-hydroxy-2'-deoxyguanosine (8-OHdG), a potential marker involved in the initiation of carcinogenesis, were measured by high-performance liquid chromatography, whereas tissue trace element status and expression of metallothionein (MT), a Cu-Zn metalloprotein associated with neoplastic cell growth and subsequent development of premalignant phenotype of the cell, were studied by energy-dispersive X-ray fluorescence spectrometry and enzyme-coupled immunohistochemistry, respectively. There was a significant and steady elevation of modified bases (8-OHdG) along with substantial increase in MT immunoexpression and disturbance in trace element homeostasis following DEN exposure. Supplementation of vanadium at a dose of 0.5 ppm for four consecutive weeks strictly abated the formation of 8-OHdG (P < 0.0001; 81.28%) in preneoplastic rat liver. In a long-term DEN plus PB regimen, vanadium was able to limit in situ MT expression with a concomitant decrease in MT immunoreactivity (P < 0.05). Furthermore, vanadium treatment throughout the study restored hepatic levels of essential trace elements and decreased nodular incidence (58.34%) and nodule multiplicity (P < 0.001; 66.89%) in rats treated with DEN plus PB. Taken together, the study provides evidence in support of the chemopreventive potential of vanadium in limiting neoplastic transformation during the preneoplastic stages of hepatocarcinogenesis in rats.

Vanadium, a Versatile Biochemical Effector in Chemical Rat Mammary Carcinogenesis

: Recent studies indicate the role of the micronutrient vanadium in chemoprevention in many animal models, human cancer cell lines, and also in xenografted human carcinomas of the lung, breast, and gastrointestinal tract. The present studies were undertaken to ascertain the antineoplastic potential of vanadium in a defined model of mammary carcinogenesis. Female Sprague-Dawley rats, at 50 days of age, were treated with 7,12-dimethylbenz(α) anthracene (DMBA) (0.5 mg/100 g body weight) by a tail vein injection in oil emulsion. Vanadium (ammonium metavanadate) at a concentration of 0.5 ppm (4.27 μmol/l) was supplemented in drinking water and given ad libitum to the experimental group after the carcinogen treatment, and it continued until the termination of the study. In vivo studies of DNA chain breaks demonstrated that vanadium offered significant (61%, P < 0.005) protection against generation of single-strand breaks when compared with the DMBA control group. Supplementation of vanadium normalizes the level of zinc, iron, and copper as revealed by proton-induced X-ray emission analysis to a substantial extent (P < 0.01). In vitro study of chromosomal aberrations (CAs) revealed that vanadium triggered a protective effect (62.9%) on induction of CAs, which was maximum on structural aberrations followed by numerical and physiological types. Histopathological and morphological analyses were done as end-point biomarkers. We conclude herein that vanadium has the potential to reduce genomic instability in mammary carcinoma in rats.

Astrophysical Estimate of Ionisation Potential of Vanadium

IN a previous letter (NATURE, June 9, 1928) I outlined the method by which estimates of ionisation potentials might be derived from the spectra of Cepheid variables. Many of the lines emitted by ionised atoms are intensified at or near maximum luminosity phase and diminish in intensity as the star passes through the phase of minimum light. Many arc lines, on the other hand, show the reverse tendency. By comparing the behaviour of certain ionised lines with spark lines due to titanium, scandium, strontium, and barium, the ionisation potentials of which are known, it has been possible to estimate this constant for iron, yttrium, and lanthanum (loc. cit.), and quite recently for vanadium. From the periodic changes in intensity of the ionised line λ4205.07 I have obtained for the ionisation potential of vanadium 6.74 volts, the final figure being extremely uncertain.