Soft chemical topotactic synthesis and crystal structure evolution from two-dimensional KV3O8 plates to one-dimensional V3O7 nanobelts

Abstract

One-dimensional (1D) V₃O₇ nanobelts preferentially exposing the (010) plane are successfully prepared by using layered structured KV₃O₈ plate-like particles as the precursor in a soft chemical topotactic synthesis process. The structure and morphology of the samples obtained at different reaction times and temperatures are investigated by using an X-ray diffractometer (XRD), a field emission scanning electron microscope (FE-SEM) and a transmission electron microscope (TEM) to explore the formation mechanism of V₃O₇ nanobelts from KV₃O₈ plate-like particles. In this process, the KV₃O₈ plate-like particles are firstly split along the a-axis direction into H⁺-form vanadate (HVO) nanobelts by dissolution and ion exchange reactions with acid treatment. Then, the HVO nanobelts are transformed into V₃O₇ nanobelts by an in situ topotactic dehydration reaction. The photoelectric performance of the obtained V₃O₇ nanobelts is evaluated by decomposing water to H₂ under simulated sunlight illumination and by measuring the accompanying photocurrent. The generated photocurrent density is 30 μA cm⁻², indicating that the (010) plane of V₃O₇ is one of the most photocatalytically active surfaces. Thus, the V₃O₇ nanobelt material has a potential application to photocatalysis.