H2O影响γ-Al2O3吸附SO2、NO的机理分析

利用分子模拟和实验探究结合，考察了H2O影响γ-Al2O3吸附SO2、NO的机理。在构造γ-Al2O3(110C)面基础模型和建立H2O，SO2，NO等吸附质分子在(110C)面的吸附模型后，确定了优化的吸附构象。通过电荷密度和分波态密度分析发现，吸附质与(110C)面Al位点存在明显的电子转移，进而形成稳定的吸附结构。H2O通过分子吸附和解离吸附，占据Al3c和O3c位点；SO2主要吸附在Al3c、Al4c位点；NO与Al4c位点相互作用，需要在O3c位点氧化。因此，H2O与SO2和NO在γ-Al2O3(110C)面的Al3c和O3c位点存在竞争吸附。试验结果与分子模拟理论分析结果基本一致，H2O不利于SO2和NO在γ-Al2O3上的吸附。

MECHANISM ANALYSIS OF EFFECT OF H2O ON ADSORPTION OF SO2 AND NO ON γ-Al2O3

The mechanism of the influence of H2O on the adsorption of SO2 and NO on γ-Al2O3 was investigated by molecular simulation and experimental investigation. The adsorption structure of γ-Al2O3 (110C) surface was constructed, and the adsorption models for H2O, SO2, NO molecules on (110C) surface were established to determine the optimized adsorption structure. It was found that there was obvious electron transfer between adsorbate and (110C) Al site by charge density and partial density of states, resulting in the formation of stable adsorption structure. H2O occupied Al3c and O3c sites through molecular adsorption and dissociation adsorption; SO2 was mainly adsorbed at Al3c and Al4c sites, while NO interacted with the Al4c sites and needed to be oxidized at the O3c sites. Therefore, there is a competitive adsorption among H2O, SO2, NO at Al3c and O3c sites on the γ-Al2O3 (110C) surface. The experimental results were basically consistent with the theoretical analysis of molecular simulation. H2O is not conducive to the adsorption of SO2 and NO on γ-Al2O3.