A novel route for the easy production of thermochromic VO2 nanoparticles

Chemistry. 2021 Oct 18. doi: 10.1002/chem.202102566. Online ahead of print.ABSTRACTIn this work, a simple, fast and dry method for the fabrication of a thermochromic product with a high load of VO 2 (M1) consisting of the controlled heat treatment of pure vanadium nanoparticles in air is presented. After a complete design of experiments, it is concluded that the most direct way to attain the maximum transformation of V into VO 2 (M1) consists of one cycle with a fast heating ramp of 42 o Cs -1 , followed by keeping 700 o C for 530-600 seconds, and a subsequent cooling at 0.05 o Cs -1 . Careful examination of these results lead to a second optimum, even more suitable for industrial production (quicker and less energy-intensive because of its lower temperatures and shorter times), consisting of subjecting V to two consecutive cycles of temperatures and times (625 o C for 5 minutes) with similar preheating but a much faster postcooling (~8 o Cs -1 ). These green reactions only use the power for heating a tube open to atmosphere and a vanadium precursor; without assistance of reactive gases or catalysts, and no special vacuum or pressure requirements. The best products present similar thermochromic properties but higher thermal stability than commercial VO 2 particles. These methods can be combined with VO 2 doping.PMID:34661929 | DOI:10.1002/chem.202102566
Source: Chemistry - Category: Chemistry Authors: Source Type: research