Zn含量对于Cu-Mn-Zn/ZrO<sub>2</sub>催化剂CO<sub>2</sub>加氢合成甲醇性能的影响研究

Zn含量对于Cu-Mn-Zn/ZrO₂催化剂CO₂加氢合成甲醇性能的影响研究

摘要: 通过溶胶-凝胶方法制备了一系列不同Zn含量的Cu-Mn-Zn/ZrO₂催化剂，并通过XRD、BET、TPR、N₂O吸附、XPS、TPD和 in-situ DRIFTS进行了表征。结果表明，随着Zn含量增加，催化剂上CO₂加氢反应的活性增加。在所有样品中，Cu₃MnZn_0.5Zr_0.5（CMZZ-0.5）在250 ℃和5 MPa条件下具有最高的CO₂转化率（6.5%）和甲醇选择性（73.7%）。表征结果表明，Zn进入Cu_1.5Mn_1.5O₄尖晶石结构，形成ZnO_x，导致催化剂表面羟基含量的增加，同时增加了Cu⁰和Cu^α+的含量，改善了H₂和CO₂的活化能力。此外，通过原位漫反射红外光谱研究了 CO₂转化为甲醇的途径。

Abstract: A series of Cu-Mn-Zn/ZrO₂ catalysts with different Zn contents were prepared by sol-gel method and characterized by XRD, BET, TPR, N₂O-adsorption, XPS, TPD and in-situ DRIFTS. It was found that by increasing a certain amount of Zn, the catalytic activity for CO₂ hydrogenation increased. Among all samples, Cu₃MnZn_0.5Zr_0.5 (CMZZ-0.5) possessed the best CO₂ conversion (6.5%) and methanol selectivity (73.7%) at 250 °C and 5 MPa. Characterization results showed that Zn entered the Cu_1.5Mn_1.5O₄ spinel structure, forming ZnO_x and thus more surface OH groups. This increased the content of Cu⁰ and Cu^α+, which improved the activation of H₂ and CO₂. The pathway of CO₂ to methanol was also clarified through in-situ DRIFTS.