Characterization of K4Nb6O17 synthesized by a sol-gel method for H2 evolution

Abstract

K4Nb6O17 photocatalysts for H2 evolution are synthesized by a sol-gel method at different pH conditions. The produced K4Nb6O17 photocatalysts are characterized by preferred crystal planes which show high photocatalytic efficiency for hydrogen evolution in an aqueous methanol solution. The experimental results show that the pH value of the precursor solution is important in affecting the overall hydrogen production rate. Water molecules cause the distortion of the NbO6 octahedrons and affect the interlayer space. This article rationalizes the reaction mechanism and proposes the intensity ratio of X-ray diffraction (XRD) (0 12 1) and (2 3 1) peaks as an indicator of cation mixing correlating with the hydrogen evolution efficiency. The photocatalysts are examined by XRD, transmission electron microscopy (TEM), UV-visible diffusion reflection, and Raman measurements as well as structural modeling for better understanding the photocatalytic properties. © 2011 The Chinese Institute of Engineers.