Abstract: Layered K-Fe-Ti metal oxide catalysts with different K∶Fe∶Ti molar ratios were synthesized by the conventional solid-state reaction and characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-Vis diffuse reflectance spectroscopy. There were two kinds of crystal structure in the catalysts, tetragonal and orthorhombic symmetry phases, which is related to the amount of interlayer K+ ions and solid-state reaction temperature. In the UV-Vis diffuse reflectance spectra of the catalysts, the absorption peaks in the visible region appeared, and the absorption peaks at 400～550 nm were attributed to the octahedral Fe3+ species. Moreover, the excessive amount of Fe3+ ions in the materials could increase the isolated Fe2O3 species but could not affect the crystal structure of catalyst. In the presence of the electron donor, H2C2O4, the catalyst with the orthorhombic crystal phase exhibited higher photocatalytic activity for water splitting than that with the tetragonal crystal phase, but the latter showed better reaction stability for the hydrogen evolution from water.

Key words: layered metal oxide, solid-state reaction, photocatalysis, hydrogen