Reboredo Fernando A, Galli Giulia
Lawrence Livermore National Laboratory, Livermore, CA 94551, USA.
J Phys Chem B. 2006 Apr 20;110(15):7979-84. doi: 10.1021/jp056291l.
We have carried out a series of ab initio calculations to investigate changes in the structural and magnetic properties of pristine cobalt clusters upon CO chemisorption. Our results show that binding energies of CO to 13-55 atom (0.5-1.5 nm) cobalt nanoparticles and preferred chemisorption sites depend on the cluster structure (whether fcc or icosahedral), size, and surface coverage. In addition, we find a strong influence of CO on the magnetism of the cluster, leading to magnetic moments smaller than in the bulk, at variance with pristine clusters which have magnetic moments larger than the bulk. Our findings suggest important changes in catalytic properties of cobalt at the nanoscale. Our theory suggests that at the nanoscale cluster size and surface coverage might control catalysis.
我们进行了一系列从头算计算，以研究原始钴团簇在CO化学吸附后结构和磁性的变化。我们的结果表明，CO与13 - 55个原子（0.5 - 1.5纳米）钴纳米颗粒的结合能以及优先化学吸附位点取决于团簇结构（无论是面心立方还是二十面体）、尺寸和表面覆盖率。此外，我们发现CO对团簇磁性有强烈影响，导致磁矩小于体相中的磁矩，这与具有大于体相磁矩的原始团簇不同。我们的发现表明钴在纳米尺度下催化性能发生了重要变化。我们的理论表明，在纳米尺度下，团簇尺寸和表面覆盖率可能控制催化作用。
