Methanol synthesis from CO2 and H-2 over Pd/ZnO/Al2O3: Catalyst structure dependence of methanol selectivity
Methanol synthesis from CO2 and H-2 over Pd/ZnO/Al2O3: Catalyst structure dependence of methanol selectivity
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Pd/ZnO/Al2O3 上 CO2 和 H-2 合成甲醇：甲醇选择性的催化剂结构依赖性
DOI：
10.1016/j.apcata.2016.01.006
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Geng Haoran
中科院分区：
文献类型：
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作者：
Xu Jinghua;Su Xiong;Liu Xiaoyan;Pan Xiaoli;Pei Guangxian;Huang Yanqiang;Wang Xiaodong;Zhang Tao;Geng Haoran
以Pd/ZnO/Al2O3为催化剂，研究了CO2加氢制甲醇的性能，重点考察了制备方法、还原温度和Pd负载量对催化性能的影响。使用各种技术彻底检查了每种催化剂的结构。结果表明，甲醇选择性取决于PdZn合金的含量，并随着催化剂的制备方法和预处理程序的变化而动态变化。更具体地说，双金属化合物中PdZn/PdO的比例随着还原温度的升高而增加，最终导致甲醇选择性的增加。此外，EXAFS 结果表明，当 Pd 负载量降低至低于 2 wt% 时，存在 ZnOx 修饰的 Pd 物质。然而，当反应在相似的 CO2 转化率下进行时，CH3OH 选择性几乎保持不变。因此，我们得出结论，PdZn合金和ZnO岛修饰的Pd都是CO2加氢合成甲醇的活性位点。
CO2hydrogenation to methanol was investigated over Pd/ZnO/Al2O3, focusing on the influence of the preparation method, reduction temperature and Pd loading on the catalytic performance. The structure of each catalyst was thoroughly examined using various techniques. The results indicated that the methanol selectivity depended on the content of PdZn alloy, which changed dynamically with varying the preparation methods and pretreatment procedures of the catalysts. More specifically, the ratio of PdZn/Pd0in the bimetallic compound increased with the rise of the reduction temperature, which eventually led to the increase of methanol selectivity. Additionally, the EXAFS results revealed the presence of ZnOxmodified Pd species when the Pd loading was decreased to be lower than 2 wt%. However, the CH3OH selectivity remained almost identical when the reactions were conducted under similar CO2conversions. Therefore, we conclude that both the PdZn alloy and Pd modified by ZnOxislands are the active sites for methanol synthesis from CO2hydrogenation.