UiO-66基催化剂的制备及其在CO甲烷化中的应用

煤制天然气技术具有良好的经济和环境效益，其中CO甲烷化是煤制天然气过程的重要环节之一。本研究以UiO-66材料为载体制备了一系列具有不同Ni负载量的Ni/UiO-66催化剂，采用XRD, BET, TG, SEM, TEM, XPS等表征方法对载体和催化剂的物相结构、织构性质、热稳定性和元素分布情况进行考察，并对各催化剂上CO加氢性能进行了考察。研究结果表明，Ni金属高度分散于UiO-66载体上，且对金属有机骨架材料的物相结构和晶体形貌无显著影响。在CO甲烷化反应过程中，随Ni负载量逐渐增加，各Ni/UiO-66催化剂的起活温度逐渐降低；在相同反应温度(320℃)下，不同催化剂上Ni负载量由10%增加到30%，其CO转化率由10.7%提升到89.7%；当Ni含量为20%时，催化剂在反应过程中具有良好的稳定性。同时，Ni基催化剂上CO转化率远高于具有相同金属负载量的Fe基和Co基催化剂，表明Ni作为活性金属在合成气制甲烷反应过程中具有优异的催化性能。

Preparation of UiO-66 based catalyst and its performance for CO methanation

Converting coal-based gas to natural gas has great economic and environmental benefits. As coal gasification technology matures, the CO methanation process acts as an important role. MOFs materials have shown excellent performance in many fields and have attracted more and more attention. Compared with conventional catalysts, UiO-66 is a Zr-based MOFs material with high specific surface area and good thermal and chemical stability, the active metal Ni has low cost and is equivalent to the catalytic hydrogenation ability of precious metals. In present study, a series of UiO-66 catalysts with Ni loading were prepared via ultrasonic impregnation method. Plenty of characterizations including XRD, BET, TG, SEM, TEM and XPS were used to study the structure, textual properties, thermal stability and morphology of the UiO-66 supported Ni-based catalysts. The catalytic performance of different catalysts was also evaluated in the fixed-bed reactor. The results showed that the Ni was reduced to metallic state in the prepared catalyst, the Ni metal was highly dispersed on the UiO-66 support and exhibited no significant effect on the framework structure and crystal morphology of the MOF material. The structure of the carrier did not change below 400℃. In the CO methanation reaction, the activation temperature of the Ni/UiO-66 catalysts gradually decreased with the increase of Ni loading content. At the same reaction temperature (320℃), the Ni content on different catalysts increased from 10% to 30%, the CO conversion increased from 10.7% to 89.7%.When the Ni content was 20%, the catalyst showed good stability during the reaction process. Meanwhile, the CO conversion on the Ni-based catalyst was much higher than that of the Fe-based and Co-based catalysts with the same metal content, indicating that Ni as an active metal had excellent catalytic performance in the synthesis gas to methane reaction process.