Time-based investigation of the growth of VO2(B) micro- and nanostructures on vanadium by hydrothermal synthesis

► Hydrothermal synthesis of VO2(B) from V metal in H2O occurred in 2 h instead of 7 days. ► V metal strip inclined 70° to the vertical in a partly filled autoclave gave 2 kinds of micro/nanostructures. ► Nanostructured VO2 exfoliated microspheres grew on V strip above H2O, VO2 parallelipeds grew under H2O. ► FT-IR and XPS suggest existence of VO2 and V2O3 in samples. ► A mechanism of growth is proposed.