【摘要】 采用等体积浸渍法制备了Na2SO4改性的Mn/SiO2催化剂,考察了Mn-Na2SO4/SiO2催化剂中各组分对甲烷氧化偶联合成C2产物(C2H4+C2H6)的影响,并采用X射线衍射、X射线光电子能谱、Raman光谱和程序升温还原等手段表征了催化剂中的物相结构、表面组分价态与含量以及氧化还原性能.结果表明,在Mn/SiO2催化剂中添加Na2SO4可使载体SiO2由无定形转变为α-方石英相,使催化剂表面的Mn物种由Mn3O4转变为Mn2O3,从而大大提高了甲烷转化率和目标产物C2的选择性.因此,推测Mn2O3物种在反应条件下构成了甲烷氧化偶联反应的活性中心.更多还原

【Abstract】 The oxidative coupling of methane to C₂ hydrocarbons（C₂H₄ and C₂H₆） was examined on Mn-Na₂SO₄/SiO₂.The catalysts were characterized using X-ray diffraction,X-ray photoelectron spectroscopy,laser Raman spectroscopy,and temperature-programmed reduction with H₂.The addition of Na₂SO₄ to Mn/SiO₂ led to the exclusive transformation of amorphous SiO₂ to α-cristobalite and the concurrent oxidation of Mn₃O₄ to Mn₂O₃.The observed effects on the structure and catalytic performance suggest that Mn₂O₃ species act as the active sites for the methane activation,which may provide the basis for the rational design of new efficient catalysts for the oxidative coupling of methane.更多还原