Adsorption of Nin (n=1-4) clusters on perfect and O-defective CuAl2O4 surfaces: A DFT study

The density functional theory was employed to investigate the adsorption of Ni-n (n = 1-4) on the perfect and O-defect CuAl2O4 surfaces. The computational results show that for single Ni atom on the perfect spinel (100) surface, the adsorption energy is -5.30 eV, much larger than Ni on other CuAl2O4 surfaces. The adsorption of Ni-n (n = 1-4) absorbed on the O-defect CuAl2O4 (100) surface is less stable than on the perfect CuAl2O4 (100) surface. However, the adsorption energy for Ni-n (n = 1-4) on the O-defect CuAl2O4 (110) surface is close to on the perfect CuAl2O4 (110) surface. Bader charge and partial density of states (PDOS) analysis revel that the adsorption of Ni on the CuAl2O4 spinel surface is accompanied by charge transfer from the metal to the support. The growth and aggregations analysis show that the general growth and aggregation ability for Ni-n clusters follow the order: gas phase > gamma-Al2O3 (110) > CuAl2O4 (110) > CuAl2O4 (100). This result can give reasonable explanations for the experimental phenomenon that Ni supported on the CuAl2O4 spinel performs much better stability than on the gamma-Al2O3. (C) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.