【摘要】 本文应用脉冲色谱和红外光谱研究了镍基变换-甲烷化催化剂的H₂S中毒对CO和H₂O的 吸附、离解及反应的影响。观察到H₂S首先吸附在CO的桥式吸附中心上,并在体相形成镍同 硫的化合物。CO的线式吸附中心中毒较为缓慢。H₂S的饱和吸附使CO的歧化反应活性降 低,并使水的离解吸附停止进行。中毒的催化剂完全失去变换-甲烷化活性,但仍有一定的变 换反应和CO歧化反应活性。催化剂上表面炭的存在对H₂S中毒有一定的阻碍作用。更多还原

【Abstract】 The influence of H2S poisoning on CO and H2O adsorption, dissociation and reaction over a nickel catalyst was studied by pulse reaction technique and infrared spectroscopy. It is found that H2S is first adsorbed on the nickel sites for bridged adsorbed CO. Then sulfur immigrates into bulk phase of the catalyst to form sulfur compound with nickel. The nickel/sulfur molar ratio is about 3:2. At lower H2S pressure (≤1.4×10-3kPa), the linear adsorbed CO species are increased and only a little bridged adsorbed CO species remains. This indicates the poisoning of nickel sites for linear CO adsorption by H2S is slower than that for bridged adsorption. The activity of nickel catalyst for shift-methanation decreases with the increase of adsorbed H2S, and is completely lost when H2S adsorption is saturated.Saturated adsorption of H2S leads to the stopping of dissociation of H2O, but the disproportionation reaction of CO and water gas shift reaction can still proceed with rather low level of activity. Poisoning effect by H2S can be partly hindered by the deposition of large amount of carbon on the surface of catalyst. The catalyst with carbon deposition has still the activity for shift-methanation and on which the bridged adsorbed species of CO (1930cm-1) are detected.更多还原