Ni/ZrO_(2)-SO_(4)^(2-)催化剂的制备及其催化甲烷与CO_(2)制乙酸性能

Preparation of Ni/ZrO_(2)-SO_(4)^(2-)catalyst and its catalytic performance for synthesis of acetic acid from methane and CO_(2)

以Zr(NO_(3))4·5H_(2)O和Ni(NO_(3))2·6H_(2)O为原料、(NH4)2CO_(3)为沉淀剂,采用溶胶凝胶-硫酸酸化两步法制备了Ni/ZrO_(2)-SO_(4)^(2-)催化剂,采用XRD,FTIR,SEM,N_(2)吸附-脱附,H_(2)-TPR,NH3-TPD等方法对Ni/ZrO_(2)-SO_(4)^(2-)催化剂进行表征,考察了Ni的引入方式对催化剂的结构和性能的影响。实验结果表明,与共沉淀方式引入Ni制备的Ni/ZrO_(2)-SO_(4)^(2-)催化剂相比,采用溶胶凝胶方式引入Ni制备的催化剂的四方相ZrO_(2)占比更高,表面酸量更多,且具有良好的热稳定性和较强的L酸性;采用溶胶凝胶方式引入Ni制备的Ni/ZrO_(2)-SO_(4)^(2-)催化剂的乙酸生成量明显优于共沉淀方式引入Ni制备的Ni/ZrO_(2)-SO_(4)^(2-)催化剂。四方相ZrO_(2)、酸性位点和过渡金属Ni之间的协同作用促进了甲烷与CO_(2)直接反应合成乙酸。

Using Zr(NO_(3))4·5H_(2)O and Ni(NO_(3))2·6H_(2)O as raw materials and(NH4)2CO_(3) as precipitant,the Ni/ZrO_(2)-SO_(4)^(2-)catalyst was prepared by a two-step method of sol-gel and sulfuric acid acidification.The catalyst was characterized by XRD,FTIR,SEM,N_(2) adsorption-desorption,H_(2)-TPR,NH3-TPD and other methods,and the effects of different introduction methods of Ni on the structure and catalytic performance of the catalyst were investigated.The experimental results show that compared with the Ni/ZrO_(2)-SO_(4)^(2-)catalyst prepared by introducing Ni through coprecipitation method,the catalyst prepared by introducing Ni through sol-gel method has a higher proportion of tetragonal phase ZrO_(2),more surface acid content,and better thermal stability and stronger acidity of L-acid.The acetic acid production by the Ni-introduced catalyst through sol-gel method is significantly better than that through coprecipitation method.The synergistic effect among tetragonal ZrO_(2),acidic sites and transition metal Ni promotes the direct reaction of methane and CO_(2) to synthesize acetic acid.