Chinese Journal of Catalysis ( IF 16.5 ) Pub Date : 2021-06-22 , DOI: 10.1016/s1872-2067(21)63809-3 Bing Yan , Wen-Duo Lu , Jian Sheng , Wen-Cui Li , Ding Ding , An-Hui Lu
The discovery of the high activity and selectivity of boron-based catalysts for oxidative dehydrogenation (ODH) of alkanes to olefins has attracted significant attention in the exploration of a new method for the synthesis of highly active and selective catalysts. Herein, we describe the synthesis of porous boron-doped silica nanofibers (PBSNs) 100–150 nm in diameter by electrospinning and the study of their catalytic performance. The electrospinning synthesis of the catalyst ensures the uniform dispersion and stability of the boron species on the open silica fiber framework. The one-dimensional nanofibers with open pore structures not only prevented diffusion limitation but also guaranteed high catalytic activity at high weight hourly space velocity (WHSV) in the ODH of alkanes. Compared to other supported boron oxide catalysts, PBSN catalysts showed higher olefin selectivity and stability. The presence of Si−OH groups in silica-supported boron catalysts may cause low propylene selectivity during the ODH of propane. When the ODH conversion of ethane reached 44.3%, the selectivity and productivity of ethylene were 84% and 44.2% gcat−1 s−1, respectively. In the case of propane ODH, the conversion, selectivity of olefins, and productivity of propylene are 19.2%, 90%, and 76.6 μmol gcat−1 s−1, respectively. No significant variations in the conversion and product selectivity occurred during 20 h of operation at a high WHSV of 84.6 h−1. Transient analysis and kinetic experiments indicated that the activation of O2 was influenced by alkanes during the ODH reaction.
中文翻译:
用于轻烷烃氧化脱氢的多孔掺硼二氧化硅纳米纤维的静电纺丝合成
硼基催化剂用于烷烃氧化脱氢(ODH)制烯烃的高活性和选择性的发现在探索合成高活性和选择性催化剂的新方法中引起了极大的关注。在此,我们描述了通过静电纺丝合成直径为 100-150 nm 的多孔掺硼二氧化硅纳米纤维 (PBSNs) 及其催化性能的研究。催化剂的静电纺丝合成确保了硼物种在开放二氧化硅纤维骨架上的均匀分散和稳定性。具有开孔结构的一维纳米纤维不仅防止了扩散限制,而且保证了烷烃 ODH 在高重时空速 (WHSV) 下的高催化活性。与其他负载型氧化硼催化剂相比,PBSN 催化剂表现出更高的烯烃选择性和稳定性。二氧化硅负载的硼催化剂中 Si-OH 基团的存在可能导致丙烷 ODH 过程中丙烯选择性低。当乙烷的ODH转化率达到44.3%时,乙烯的选择性和产率分别为84%和44.2% gcat -1 s -1分别。在丙烷ODH的情况下,烯烃的转化率、选择性和丙烯的生产率分别为19.2%、90%和76.6 μmol g cat -1 s -1。在 84.6 小时-1的高 WHSV 下运行 20 小时期间,转化率和产品选择性没有发生显着变化。瞬态分析和动力学实验表明,在ODH反应过程中,O 2的活化受到烷烃的影响。