Hydrothermal Synthesis of Phase-Changing Vanadium Dioxide Nanoparticles and Their Use in Environmental Remediation

Abstract

Vanadium dioxide (VO2) is a unique transition metal oxide that undergoes a first-order phase transition at 68°C from a semiconducting monoclinic phase (M) to a metallic rutile phase (R). This has made VO2 of great interest in the field of condensed matter physics, but its potential applications as a chemical sensor or catalyst have been relatively ignored. VO2(M) nanoparticles were hydrothermally synthesized on a gram scale without the need for additional treatments as with other known synthesis methods. Particle films were analyzed via four-point resistivity to determine the collective phase transition behavior. Glassy carbon electrodes were modified with VO2 particles and used to detect 2,4,6-trinitrotoluene (TNT) in solution with a limit of detection of 5 parts per billion. VO2 particles were also incorporated into carbon paste electrodes and used to reduce CO2 in a solution of sodium bicarbonate. Inclusion of VO2 shifted the onset of CO2 reduction 200 mV more positive than carbon paste alone.