Applied Catalysis B: Environmental, Vol.214, 78-88, 2017
The influence of different Cu species onto multi-copper-contained hybrid materials' photocatalytic property and mechanism of chlorophenol degradation
In this paper, we synthesized a series of novel layered double hydroxides (LDHs) based materials with different organic/inorganic Cu species ((CuO)-O-3/CuCr1 (CuISB)-I-2-LDHs). The Cu species were distributed in the layers (defined as Cu-1), intercalated between the layers (Cu-2) and combined on the surface of the material (Cu-3), respectively. The percentage of each Cu specie was adjusted to reveal the connection between different modifications and their photocatalytic activities as well as the modifications and the mechanism towards the chlorophenol (2,4,6-TCP) degradation. The experimental results showed that photodegradation of TCP varied due to different Cu species, the catalyst with the highest Cu concentration between the layers had the highest TCP degradation rate of 95.1%. In addition, the apparent quantum efficiency of different (CuO)-O-3/(CuCr)-Cr-1-Cu-2/SB-LDH materials was at the range of 0.42% to 0.60%, which was higher than that of CuCr-LDHs (0.21%) and CuCr-CuSB-LDHs (0.32%). The free radical tests showed that different Cu species determined the generation of hydroxyl radical, super oxide free radical and peroxy radicals, differently. These three radicals contributed to 46.2%, 22.5% and 10.9%, respectively, for TCP degradation during the photocatalytic reaction. Therefore, it is critical to study the influence of different Cu modifications to the improvement of photocatalytic reactivity and selectivity of (CuO)-O-3/(CuCr)-Cr-1-Cu-2/SB-LDH material. In addition, the intermediates, pathway and photoreaction mechanism of TCP degradation were also investigated in detail. (C) 2017 Elsevier B.V. All rights reserved.
Keywords:Layered double hydroxides;Cu species;Photocatalysis;Chlorophenol (2,4,6-TCP);Active free radicals