Theoretical study on the structure and catalytic activity of Ni-Co-B amorphous alloy

the literature, there is little work could be found about the calculation o f amorphous ahoy, since the structure of amorphous alloy is ambiguous now. In this paper, a series of models were selected to reflect both the charact er of amorphous alloy and the change of cobalt content in Ni - Co - B amorp hous alloy. These models were calculated by SCC - DV - Xa method, the catal ytic activity and the EXAFS structure of Ni - Co - B amorphous alloy could be interpreted by the calculation results very well. The calculated results showed that the relationships between the Fermi ener gy and the density of state near Fermi level to cobalt content in Ni - Co - B amorphous alloy are also present in a volcano shape curve. It could be i nferred from the calculation that the FMO energy of catalysts will be most close to FMO of H-2 when the contents of cobalt and nickel in the Ni - Co - B amorphous alloy are near. In the reaction of catalytic hydrogenation, th e H-H bond would be weakened by the transfer of the electron from HOMO of c atalyst to the LUMO of hydrogen. Thus the closer of these two orbital energ y levels, the higher the catalytic activity of the catalyst. The volcano - shape curve of the catalytic activity versus their cobalt content is due to the volcano - shape of their Fermi level versus their cobalt content. It is known that the amorphous - orming ability and the interaction of meta l - metalloid are related to it's Fermi level and density of states near Fe rmi level. Our calculation also shows that the amorphous forming ability is strongest when the contents of Ni and Co are near in the Ni - Co - B amorp hous alloy and meantime Ni - B interaction is the strongest. All the results confirmed that there is a synergism of Ni and Co to the str ucture of Ni - Co; B amorphous alloy and certainly these results will give a new idea to the design of novel catalyst.