Overall photocatalytic water splitting on Na2ZrxTi6-xO13 (x=0, 1) nanobelts modified with metal oxide nanoparticles as cocatalysts

In this work, we present the preparation of Na2ZrxTi6-xO13 (x = 0, 1) nanobelts through a rapid solvocombustion method. The phases exhibited stable photocatalytic activity for overall water splitting under UV light. Effect of the annealing temperature on the physicochemical properties and the catalytic performance of the materials were studied. Na2ZrTi5O13 exhibited a higher rate of H-2 evolution compared to Na2Ti6O13, and it was attributed to the incorporation of Zr4+ in the structure, which generates a distortion in the octahedral sites of the structure. This distortion promoted an enhanced charge transport and a reduction in the recombination of the free carriers and a higher photocatalytic activity. The nanobelts were superficially modified through the deposition of metal oxide nanoparticles as cocatalyst, MO (M = Ni, Cu). The incorporation of metal oxide nano particles improved the charge separation process and the overall efficiency. An integral study of the structural, morphological, textural, optical and photoelectrochemical properties of the materials is presented and a charge transference mechanism on the semiconductor interface is proposed. The highest catalytic activity was obtained by Na2ZrTi5O13 modified with CuO (2909 mu mol g(-1)h(-1)), and corresponds to an increase of 13.6 times the activity of the bare photocatalyst. This was attributed to an improved charge separation at the interface of n-type Na2ZrTi5O13 and p-type CuO semiconductors. For the best of our knowledge, the activity exhibited for overall water splitting of Na2ZrxTi6-xO13 (x = 0, 1) nanobelts prepared by solvocombustion method and modified with the addition of MO nanoparticles in this work is higher compared to the reported in previous works. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.