Theoretical study of direct versus oxygen-assisted water dissociation on the Cu(1 1 0) surface
Theoretical study of direct versus oxygen-assisted water dissociation on the Cu(1 1 0) surface
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DOI：
10.1016/j.apsusc.2015.06.019
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发表时间：
2015-10
影响因子：
6.7
通讯作者：
Wenju Wang;Guoping Wang
中科院分区：
文献类型：
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作者：
Wenju Wang;Guoping Wang
采用密度泛函理论（DFT）方法研究了水分子在Cu（1 1 0）表面的吸附和解离反应.用弛豫法确定了H_2O在顶位、桥位和面心立方位上的吸附平衡构型。H2O优先吸附在Cu（110）表面的顶位上，OH和O容易吸附在桥位上，而H则同时吸附在桥位和面心立方位上.吸附是由于吸附物的电子轨道与铜原子的电子轨道之间的相互作用，主要发生在Cu（110）表面的顶层。研究了H2O在清洁和氧覆盖的铜表面上的脱氢反应，发现在清洁的铜表面上，H-OH和O-H解离的能垒分别为162.51和230.43 kJ mol− 1，在预吸附的O原子（Oads）的帮助下，分别降低到27.05和162.88 kJ mol− 1。这些结果表明，在氧覆盖的铜表面上，脱氢的能垒显著降低，Oad可以有效地促进H2O的分解。
Density functional theory (DFT) calculations have been employed to investigate the adsorption of water (H2O) on Cu(1 1 0) surface and the corresponding dissociation reaction. The equilibrium configurations of H2O adsorption on the top, bridge and fcc sites were determined by relaxation of the system. H2O is found to be adsorbed preferably on the top site of Cu(1 1 0) surface, OH and O are easily adsorbed on the bridge site, while H favors both bridge and fcc sites. The adsorption is attributed to the interaction between theporbitals of the adsorbates and thedorbitals of the copper atoms, predominantly on the top layer of the Cu(1 1 0) surface. The dehydrogenation of H2O on clean and oxygen-covered copper surfaces was both investigated, and we find that the energy barriers for H–OH and O–H dissociation, which is 162.51 and 230.43 kJ mol−1on clean copper surface, decreases to 27.05 and 162.88 kJ mol−1with the aid of pre-adsorbed O atom (Oads), respectively. These results indicate that the energy barrier of dehydrogenation on the oxygen-covered copper surface is remarkably lowered and Oadscan effectively promote H2O decomposition.