A promising synergistic effect of nickel ferrite loaded on the layered double hydroxide-derived carrier for enhanced photocatalytic hydrogen evolution

摘要

In this study, an attempt was made to modify the photocatalytic properties of an ion exchangeable semiconductor material to enhance the efficiency of hydrogen production. Visible-light active NiFe2O4 was loaded onto Ni Zn/Cr layered double hydroxide (LDH) (Ni/Zn molar ratio = 75/25) with the Fe/Cr molar ratio of 0.005, 0.010, and 0.015 as cocatalyst through a simple solvothermal process and subsequently subjected to calcination at temperature of 500 degrees C. The results revealed that the presence of the loaded cocatalyst significantly facilitated the photocatalytic activity and the mixed oxide with Fe/Cr = 0.010 displayed the highest photocatalytic activity for visible light-induced H-2 generation. The optimal amount of hydrogen evolution reached to 269.44 mu gmolh(-1) under visible light (lambda > 420 nm), which is far superior to that of the pristine Ni Zn/Cr LDH-derived oxides material (130.85 mu gmolh-1), indicating the important catalytic role of NiFe2O4. The significant enhancement in photoactivity was attributed to the synergistic effect of nickel ferrite attached on the external surface of the calcined brucite-like sheets of the LDH. The cocatalyst NiFe2O4 nanoparticles increase the donor or acceptor levels in comparison with the pristine Ni Zn/Cr LDH-derived semiconductor oxide. Moreover, the existence of sheet like LDH-derived carrier could inhibit the rapid recombination of photogenerated electrons and holes, (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.