Theoretical Sciences Unit and School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064 India.
J Chem Phys. 2018 Nov 7;149(17):174701. doi: 10.1063/1.5053968.
Au nanoparticles are promising catalysts for industrially important reactions. Their catalytic activity is known to depend on their charge state and morphology. Using density functional theory calculations, we have studied how the induced charge and dimensionality of small Au clusters can be tuned by doping the oxide support that they are deposited on. We have investigated Au clusters of sizes = 1, 2, 3, and 20 on Al-doped MgO and Mo-doped CaO. We show that substitutionally doping the oxide support with an electron donor changes the cluster morphology from an upright and/or three-dimensional geometry to a flat geometry. This structural wetting transition results in an increase in the negative charge induced on the cluster and a consequent lowering in the dissociation barrier for the O atoms adsorbed on the cluster. We find that the nature of Mo and Al dopants differs: only for the former is it true that the charge state of the dopant atoms depends on the presence or absence of Au nanoparticles and their size.
金纳米粒子是工业上重要反应的有前途的催化剂。已知其催化活性取决于其电荷状态和形态。我们使用密度泛函理论计算研究了通过掺杂其上沉积的氧化物载体，如何调节小 Au 团簇的诱导电荷和维度。我们研究了在 Al 掺杂的 MgO 和 Mo 掺杂的 CaO 上尺寸为 = 1、2、3 和 20 的 Au 团簇。我们表明，用电子供体替代掺杂氧化物载体将改变团簇的形态，从垂直和/或三维几何形状转变为平面几何形状。这种结构的润湿转变导致在团簇上诱导的负电荷增加，并且吸附在团簇上的 O 原子的离解势垒降低。我们发现 Mo 和 Al 掺杂剂的性质不同：只有前者是掺杂原子的电荷状态取决于是否存在 Au 纳米粒子及其尺寸。
