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

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 H-2 under simulated sunlight illumination and by measuring the accompanying photocurrent. The generated photocurrent density is 30 mu A 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.