2D single- or double-layered vanadium oxide nanosheet assembled 3D microflowers: controlled synthesis, growth mechanism, and applications.

A facile one-pot solvent-thermal method was developed to synthesize a unique 3D microflower structure assembled from single- or double-layered 2D nanosheets of V4O9 (F-VO). Simply by controlling the precursor concentration, yolk-shelled V4O9 (YS-VO) or bulk V4O9 (B-VO) can be produced instead. The precursor-concentration dependent growth mechanism is proposed. The exceptional catalytic/electrochemical properties and large specific surface area of F-VO promise a wide range of applications. As a proof-of-concept demonstration, we investigate its use in high-performance supercapacitors (~392 F g(-1)), and for sensitive detection of H2O2 (with a low detection limit of ~0.1 μM) and methanol (with a low detection limit of ~60 μM). Furthermore, we show that F-VO greatly outperforms its counterparts (YS-VO and B-VO) presumably owing to its unique structure and crystal plane orientation.