Controllable synthesis of ultrathin vanadium oxide nanobelts via an EDTA-mediated hydrothermal process

Ultrathin VO₂ nanobelts with rough alignment features are prepared on the induction layer-coated substrates by an ethylenediaminetetraacetic acid (EDTA)-mediated hydrothermal process. EDTA acts as a chelating reagent and capping agent to facilitate the one-dimensional (1D) preferential growth of ultrathin VO₂ nanobelts with high crystallinities and good uniformities. The annealed induction layer and concentration of EDTA are found to play crucial roles in the formation of aligned and ultrathin nanobelts. Variation in EDTA concentration can change the VO₂ morphology of ultrathin nanobelts into that of thick nanoplates. Mild annealing of ultrathin VO₂ nanobelts at 350 ℃ in air results in the formation of V₂O₅ nanobelts with a nearly unchanged ultrathin structure. The nucleation and growth mechanism involved in the formations of nanobelts and nanoplates are proposed. The ethanol gas sensing properties of the V₂O₅ nanobelt networks-based sensor are investigated in a temperature range from 100 ℃ to 300 ℃ over ethanol concentrations ranging from 3 ppm to 500 ppm. The results indicate that the V₂O₅ nanobelt network sensor exhibits high sensitivity, good reversibility, and fast response-recovery characteristics with an optimal working temperature of 250 ℃.