【摘要】 运用密度泛函理论研究了NO在CuCr2O4(100)表面4个可能吸附位的顶位吸附。结果表明:表面铜(Cu)和铬(Cr)为活性吸附位,吸附能分别为98.1kJ·mol-1和92.9kJ·mol-1。对活性吸附位Cu位和Cr位考虑了NO以N端和O端2种吸附取向的吸附,发现N端吸附比O端吸附更为有利,O端吸附为简单的物理吸附。在2种吸附取向情况下,N-O键的伸缩振动频率都发生了红移。Mulliken布居分析表明,N端吸附时NO分子失去电子;对NO吸附前后的态密度分析可知,对Cu位和Cr位N端吸附NO的2π轨道得到电子。本文并进一步讨论了NO分子在CuCr2O4(100)表面Cu位和Cr位的成键机理。更多还原

【Abstract】 The adsorption of NO on spinel-type CuCr2O4 (100) surface has been studied within the framework of density functional theory (DFT). Four possible on-top sites designated as surface Cu and Cr,surface Osuf and subsurface Osub were considered. The results show that Cu site and Cr site adsorptions through N-down are energetically active with adsorption energies 98.1 kJ·mol-1 and 92.9 kJ·mol-1,respectively. For active sites,Cu site and Cr site,N-down adsorption is preferred than the O-down one and the latter is considered to be physisorption. The red shifts for N-O bond toke place at the two orientations. The Mulliken population analysis indicates NO molecules lose electrons. NO 2π antibonding orbitals get electrons for adsorptions at Cu site and Cr site by means of density of states analysis. We also further discussed the bonding mechanism for NO adsorptions at active Cu site and Cr site of CuCr2O4 (100) surface.更多还原