One-dimensional (1D) V 3 O 7 nanobelts preferentially exposing the (010) plane are successfully prepared by using layered structured KV 3 O 8 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 V 3 O 7 nanobelts from KV 3 O 8 plate-like particles. In this process, the KV 3 O 8 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 V 3 O 7 nanobelts by an in situ topotactic dehydration reaction. The photoelectric performance of the obtained V 3 O 7 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 μA cm −2 , indicating that the (010) plane of V 3 O 7 is one of the most photocatalytically active surfaces. Thus, the V 3 O 7 nanobelt material has a potential application to photocatalysis.

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A simple and efficient protocol developed for one pot three-component synthesis of 2,4,6-triarylpyridines from aromatic aldehydes, substituted acetophenones and ammonium acetate using the versatile super Brønsted acid triflimide (HNTf 2 ) as an effective catalyst is described. The reactions proceed well in the presence of 1 mol% of HNTf 2 at 80 C under solvent-free conditions and provide the corresponding triarylpyridines in good to excellent yields. The method reported has several advantages such as a metalfree and commercially available catalyst, mild reaction conditions and lower loading of catalyst.