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Shape-Controlled CeO2 Nanoparticles: Stability and Activity in the Catalyzed HCl Oxidation Reaction
ACS Catalysis ( IF 12.9 ) Pub Date : 2017-08-28 00:00:00 , DOI: 10.1021/acscatal.7b01618
Chenwei Li 1, 2 , Yu Sun 1 , Igor Djerdj 3 , Pascal Voepel 2 , Carl-Christian Sack 2 , Tobias Weller 2 , Rüdiger Ellinghaus 2 , Joachim Sann 2 , Yanglong Guo 1 , Bernd M. Smarsly 2 , Herbert Over 2
Affiliation  

CeO2 is a promising catalyst for the HCl oxidation (Deacon process) in order to recover Cl2. Employing shape-controlled CeO2 nanoparticles (cubes, octahedrons, rods) with facets of preferential orientations ((100), (111), (110)), we studied the activity and stability under two reaction conditions (harsh: Ar:HCl:O2 = 6:2:2 and mild: Ar:HCl:O2 = 7:1:2). It turns out that both activity and stability are structure-sensitive. In terms of space time yield (STY), the rods are the most active particles, followed by the cubes and finally the octahedrons. This very same trend is reconciled with the complete oxygen storage capacity (OSCc), indicating a correlation between the observed activity STY and the OSCc. The apparent activation energies are about 50 kJ/mol for cubes and rods, while the octahedrons reveal an apparent activation energy of 65 kJ/mol. The reaction order in O2 is positive (0.26–0.32). Under mild reaction conditions, all three morphologies are stable, consistent with corresponding studies of CeO2 powders and CeO2 nanofibers. Under harsh reaction conditions, however, cubes and octahedrons are both instable, forming hydrated CeCl3, while rods are still stable. The present stability and activity experiments in the catalytic HCl oxidation reaction over shape-controlled CeO2 nanoparticles may serve as benchmarks for future ab initio studies of the catalyzed HCl oxidation reaction over well-defined CeO2 surfaces.

中文翻译:

形状控制的CeO 2纳米颗粒:催化HCl氧化反应的稳定性和活性

CeO 2是用于回收Cl 2的HCl氧化(迪肯工艺)的一种有前途的催化剂。使用形状控制的CeO 2纳米粒子(立方体,八面体,棒),其小平面具有优先取向((100),(111),(110)),我们研究了在两种反应条件下的活性和稳定性(苛刻条件:Ar:HCl: O 2 = 6:2:2中等:Ar:HCl:O 2= 7:1:2)。事实证明,活性和稳定性都是结构敏感的。就时空产率(STY)而言,棒是最活跃的粒子,其次是立方体,最后是八面体。这种完全相同的趋势与总储氧量(OSCc)相符,表明观察到的活性STY和OSCc之间存在相关性。立方体和棒的表观活化能约为50 kJ / mol,而八面体的表观活化能为65 kJ / mol。O 2中的反应阶数为正(0.26-0.32)。在温和的反应条件下,所有三种形态都是稳定的,与CeO 2粉和CeO 2的相应研究一致纳米纤维。然而,在苛刻的反应条件下,立方体和八面体都不稳定,形成水合的CeCl 3,而棒仍然稳定。目前在形状受控的CeO 2纳米颗粒上进行的HCl催化氧化反应中的稳定性和活性实验,可以作为将来在明确定义的CeO 2表面上催化的HCl氧化反应进行从头研究的基准。
更新日期:2017-08-28
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