Controllable synthesis of hexagonal and orthorhombic YFeO3 and their visible-light photocatalytic activities

Single phase hexagonal and orthorhombic YFeO3 were prepared by a citric acid assisted sol–gel process. The prepared samples were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) specific surface area measurement, transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and UV–Vis diffuse reflectance spectroscopy (DRS). The phase composition can be effectively controlled by changing the calcination temperature. It is found that the hexagonal form exhibits a narrow optical band gap in comparison with the orthorhombic one, and shows stronger visible-light photocatalytic activity than the orthorhombic one. Both the narrow optical band gap and unique porous structure are responsible for the high visible-light photocatalytic activity of the hexagonal form.

► YFeO3 with controllable phase composition were prepared.
► The phase content of two forms was controlled by calcination temperature.
► Hexagonal YFeO3 exhibits narrower band gap in comparison with the orthorhombic one.
► Narrow band gap promotes high visible-light photocatalytic activity of hexagonal one.