CAJ | 학술논문

以骨架Co为内核，通过水热合成在其表面包覆HZSM-5分子筛膜，制备了具有核壳结构的骨架Co@HZSM-5催化剂。采用元素分析、氮物理吸附、粉末X射线衍射、扫描电子显微镜、氨脱附等手段对催化剂的物理化学性质进行了表征。在气相费托合成反应中，骨架Co@HZSM-5核壳催化剂显示了比物理混合的骨架Co-HZSM-5催化剂更好的催化裂解作用，故C5-C11汽油段产物选择性高。通过改变水热时间，对分子筛膜厚进行了调节，发现适当的分子筛膜厚在保证催化剂具有较高活性的前提下，使长链费托合成产物完全裂解，高选择性地得到汽油段产物。提高反应温度有利于费托合成反应的进行以及分子筛上裂解效率的提高，但产物分布向短链烃方向移动。在水热4天制备的骨架Co@HZSM-5核壳催化剂上及反应温度为250°C时，得到了最佳反应结果，汽油段产物选择性达79%，说明费托合成活性中心与催化裂解酸中心之间形成了良好的协同作用。
이골가Co위내핵，통과수열합성재기표면포복HZSM-5분자사막，제비료구유핵각결구적골가Co@HZSM-5최화제。채용원소분석、담물리흡부、분말X사선연사、소묘전자현미경、안탈부등수단대최화제적물이화학성질진행료표정。재기상비탁합성반응중，골가Co@HZSM-5핵각최화제현시료비물리혼합적골가Co-HZSM-5최화제경호적최화렬해작용，고C5-C11기유단산물선택성고。통과개변수열시간，대분자사막후진행료조절，발현괄당적분자사막후재보증최화제구유교고활성적전제하，사장련비탁합성산물완전렬해，고선택성지득도기유단산물。제고반응온도유리우비탁합성반응적진행이급분자사상렬해효솔적제고，단산물분포향단련경방향이동。재수열4천제비적골가Co@HZSM-5핵각최화제상급반응온도위250°C시，득도료최가반응결과，기유단산물선택성체79%，설명비탁합성활성중심여최화렬해산중심지간형성료량호적협동작용。
We used skeletal Co as the core to prepare a skeletal Co@HZSM-5 core-shel catalyst by growing an HZSM-5 membrane on skeletal Co via hydrothermal synthesis. The physicochemical properties of the catalyst were determined using elemental analysis, N2 physisorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and NH3 desorption. In gas-phase Fischer-Tropsch synthesis (FTS), the skeletal Co@HZSM-5 core-shel catalyst was more efficient than a physical y mixed skeletal Co-HZSM-5 catalyst in cracking long-chain hydrocarbons, giving higher selectivity for C5-C11 gasoline products. The thickness of the zeolite shel on the skeletal Co@HZSM-5 core-shel catalyst was easily tuned by adjusting the hydrothermal time. At a suitable zeolite shel thickness, the long-chain hydrocarbons were cracked completely, with high FTS activity, leading to high selectivity for the gasoline fraction. Increasing the reaction temperature resulted in higher FTS and cracking activities, but the product distribution shifted to short-chain hydrocarbons. For the optimum skeletal Co@HZSM-5 core-shel catalyst, which was subjected to hydrothermal treatment for 4 d, selectivity for the gasoline fraction reached 79%at 250 °C, which shows an excel ent synergistic effect between the FTS active sites and the acidic sites on this catalyst.