Ab Initio Density Functional Calculations of Adsorption of Transition Metal Atoms on θ-Al2O3(010) Surface
Ab Initio Density Functional Calculations of Adsorption of Transition Metal Atoms on θ-Al2O3(010) Surface
复制标题
DOI：
10.1021/jp209725a
复制
发表时间：
2012-03-08
影响因子：
3.7
通讯作者：
Stocks, G. Malcolm
中科院分区：
文献类型：
--
作者：
Narula, Chaitanya K.;Stocks, G. Malcolm
金属簇和颗粒的催化性能取决于它们的环境;然而，迄今为止对亚纳米金属颗粒知之甚少，最小的是单原子，负载在金属氧化物基底上，特别是可以通过实验合成的系统。采用第一性原理密度泛函理论方法，研究了Ni，Pt，Pd，Cu，Au，Ag等金属原子在θ-Al_2 O_3（010）表面的吸附.结果表明，金属在干燥的θ-Al 2 O3表面的吸附强度顺序为Pd > Pt > Ni > Cu > Au > Ag。有趣的是，Ni、Pt和Pd原子，支撑在θ-氧化铝上，不显示磁化，而Cu、Ag和Au显示未成对电子。从这项研究中出现的键合图片显示，Ni，Pt和Pd，是d（10）物种与d-s杂化字符，能够与表面氧的2 p轨道相互作用。第11族（Cu，Ag，Au）原子与θ-Al_2 O_3表面的相互作用与第10族金属表面的相互作用相似。具有填充d轨道的第11族金属由于比第10族金属更大的能隙而具有较低的d-s杂化倾向。由于与0 2 p的重叠，d轨道向较低能量移动。第11族金属的磁化主要是由于s轨道中的单电子。
The catalytic properties of metal clusters and particles depend on their environment; however, little is known so far about the subnanometer metal particles, the smallest being single atoms, supported on metal oxide substrates, in particular, the systems that can be experimentally synthesized. Employing the first-principles density functional theory approach, we have studied single metal atoms, Ni, Pt, Pd, Cu, Au, and Ag, adsorbed on a theta-Al2O3 (010) surface. We find that metal adsorption on a dry theta-alumina surface follows the binding strength order of Pd > Pt > Ni > Cu > Au > Ag. Interestingly, Ni, Pt, and Pd atoms, supported on theta-alumina, exhibit no magnetization, whereas Cu, Ag, and Au exhibit unpaired electrons. The bonding picture that emerges from this study shows that Ni, Pt, and Pd, are d(10) species with d-s hybrid character that are able to interact with the 2p orbital of surface oxygen. The interaction of Group 11 (Cu, Ag, Au) atoms with 010 surface of theta-Al2O3 is superficially similar to that of Group 10 metals. Group 11 metals with filled d orbitals have low tendency for d-s hybridization due to larger energy gaps than Group 10 metals. As a result of the overlap with 0 2p, the d orbital shifts to lower energy. The magnetization of Group 11 metals is primarily due to single electrons in s orbitals.