二氧化硅负载氧化锌催化剂的溶胶-凝胶和浸渍法制备及对仲丁醇分解反应的催化性能

Catalytic Properties of SiO_2 Supported ZnO Catalysts Prepared via Sol-gel and Impregnation Methods for Decomposition of Butan-2-ol

分别采用溶胶-凝胶法和浸渍法制备了ZnO-SiO2催化剂和ZnO/SiO2催化剂并进行了表征,以仲丁醇脱氢为探针反应,研究了不同制备方法对催化剂表面ZnO物种存在状态及其催化性能的影响.结果表明,2种方法均可制备高分散的负载型ZnO催化剂.在ZnO-SiO2和ZnO/SiO2催化剂上,仲丁醇分别以脱水和脱氢反应为主.经过分析,催化剂上ZnO物种的存在状态是影响产物选择性的关键因素,而2种催化剂表面的粒径、比表面积和表面酸碱性不是影响该反应选择性的根本原因.

ZnO-SiO2 and ZnO/SiO2 catalysts were prepared via sol-gel and impregnation methods, respective- ly. The catalysts were characterized and tested with the decomposition of butan-2-ol as a probe reaction, and the relationship between the state of the ZnO and the catalytic properties of the samples prepared via the two different methods was investigated. The results showed that ZnO nanoparticles were obtained in all the sam- ples. The opposite selectivities for dehydration and dehydrogenation were observed on the ZnO-SiO2 and ZnO/ SiO2 catalysts. Characterization results confirmed that the selectivity for dehydrogenation or dehydration had no obvious relation with the crystalsize, surface area and the surface aeidity/basicity of samples. Further studies indicated that the different selectivities to the decomposition of butan-2-ol were caused by different states of ZnO on the surface of catalysts.