The photocatalytic property for water splitting and the structural stability of CuMgM layered double hydroxides (M = Al, Cr, Fe, Ce)

In this paper, four types of CuMgM layered double hydroxides (LDHs, M = Al, Cr, Fe, Ce) with good crystal structures were successfully synthesized. The activity of those LDH materials for photocatalytic reduction of water splitting under visible light was investigated. The experimental results showed that CuMgCr-LDHs with the narrowest band gap and the largest surface areas behave with the highest efficiency for hydrogen production under visible light than the other CuMgM-LDHs. The yield for hydrogen production catalyzed by CuMgCr-LDHs was 452.9 mu mol/g h, which was very highly efficient. Furthermore, the electronic band structure of CuMgM-LDHs was analyzed by periodic density functional theory (DFT) calculation, which is in good agreement with the experimental result from UV-vis. In addition, the influence of the different M3+ on the structures and stability of the CuMgM-LDHs was also investigated by analyzing the geometric parameters, electronic arrangement, charge populations, and hydrogen-bonding and binding energies by density functional theory (DFT) analysis. The theoretical calculation results showed that the structural stability of LDH materials followed the order of CuMgAl > CuMgCe > CuMgFe > CuMgCr, while the experimental results indicated that the photocatalytic activity of the four materials followed the order of CuMgCr > CuMgFe > CuMgCe > CuMgAl. (C) 2015 Elsevier B.V. All rights reserved.