Density Functional Theory Study Of Electronic Structure And Interaction Of Pd,La Modified γ-Al₂O₃(110D) Surface

The modified methods containing deposited or doped transition metals,rare earth were adopted to enchanting the catalytic activity ofγ-Al₂O₃. For understanding the surface electronic structure,revealing the mechanism of surface reactivity and synthesizing new burning catalyst, it is necessary to study the behavior of Pd,La modifiedγ-Al₂O₃(110D)surface. With decade years ascribe to the increasing of computation level and methods, the Density Functional Theory has gone through a rapid development, and has been used to investigate the metal-oxide system. In this paper, a systematic investigation of Pd atoms,dimers and La modifiedγ-Al₂O₃ surface has been carried out by means of periodic DFT calculation. The calculated content as follows:(1) At first we optimized theγ-Al₂O₃(100),(110D)surface and considered the surface relaxation. The result showed theγ-Al₂O₃(110D)surface is more stable than the(100)surface. We have obtained the most favorite adsorption site, electron transfer through calculated the CH_x(x=0～4)species on theγ-Al₂O₃(110D)surface.(2) For Pd atoms, dimers deposited onγ-Al₂O₃(110D)surface, the calculated result showed Pd prefer to bind on bridge site of two O(2f)ofγ-Al₂O₃(110D)surface; dimers prefer to bonding with Al, O of surface. The Pd is active surface site for the deposited system.(3) For La adsorption onγ-Al₂O₃(110D)surface, we calculated the structure, energy, density of states and work function change and compared with system of La dopedγ-Al₂O₃(110D)surface. The results showed that after doping La,γ-Al₂O₃(110D)surface electronic easier to leave the surface, formation of electron hole, raiseγ-Al₂O₃ (110D)surface activity.