RT journal article
T1 Reactivity of Vanadium Nanoparticles with Oxygen and Tungsten
A1 Morales Sánchez, Francisco Miguel
A1 Escanciano, Marta
A1 Yeste Siguenza, María del Pilar
A1 Santos Izquierdo-Bueno, Antonio Jesús
A2 Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica
K1 vanadium oxidation
K1 vanadium dioxide synthesis
K1 vanadium dioxide doping
K1 X-ray diffraction
K1 differential scanning calorimetry
AB A mechanistic study was carried out on the optimal methods of fabrication of products containing higher loads of thermochromic VO2(M1) fabricated by thermal treatments of V nanoparticles in air, that, once achieved, are more stable than other commercial products upon natural aging or reiterated reheating. At the best temperatures for single runs, 55% of VO2 can be attained by the reactions of a limited number of the species initially formed in a process, that, if not stopped, can degrade the product by solid state reactions of oxidations and reductions without O-2 consumption. This fact supports the use of two-step treatments at lower temperatures and faster cooling rates that reach 65% of VO2; such reactions should, ideally, take place in the 550-625 degrees C temperature range. The impregnation of V with a tungstate salt is an ideal and simple doping platform that can decrease the energy of activation of the 2-cycle process, allowing higher yields and enthalpies of transformation (71% of VO2, 26 J/g) than undoped counterparts or trademarks. A good balance is reached for 1% at. of W, with a reduction in T-c of 20 degrees C not significantly resenting the enthalpy of the reversible metal-to-insulator transition. For higher W amounts, the appearance of tetragonal VO2, and W alloyed V3O7 and V2O5, decrease the fractions of increasingly and effectively doped M1-VO2 achieved till 2% of W, a concentration for which T-c attains the stimulating values of 35 degrees C on heating and 25 degrees C on cooling.
PB MDPI
SN 2079-4991
YR 2022
FD 2022-05
LK http://hdl.handle.net/10498/27094
UL http://hdl.handle.net/10498/27094
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 06-nov-2026