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Role of Sn in the Regeneration of Pt/γ-Al2O3 Light Alkane Dehydrogenation Catalysts
ACS Catalysis ( IF 11.3 ) Pub Date : 2016-03-02 00:00:00 , DOI: 10.1021/acscatal.5b02917
Hien N Pham 1 , Jesper J H B Sattler 2 , Bert M Weckhuysen 2 , Abhaya K Datye 1
Affiliation  

Alumina-supported Pt is one of the major industrial catalysts for light alkane dehydrogenation. This catalyst loses activity during reaction, with coke formation often considered as the reason for deactivation. As we show in this study, the amount and nature of carbon deposits do not directly correlate with the loss of activity. Rather, it is the transformation of subnanometer Pt species into larger Pt nanoparticles that appears to be responsible for the loss of catalytic activity. Surprisingly, a portion of the Sn remains atomically dispersed on the alumina surface in the spent catalyst and helps in the redispersion of the Pt. In the absence of Sn on the alumina support, the larger Pt nanoparticles formed during reaction are not redispersed during oxidative regeneration. It is known that Sn is added as a promoter in the industrial catalyst to help in achieving high propene selectivity and to minimize coke formation. This work shows that an important role of Sn is to help in the regeneration of Pt, by providing nucleation sites on the alumina surface. Aberration-corrected scanning transmission electron microscopy helps to provide unique insights into the operating characteristics of an industrially important catalyst by demonstrating the role of promoter elements, such as Sn, in the oxidative regeneration of Pt on γ-Al2O3.

中文翻译:


Sn在Pt/γ-Al2O3轻质烷烃脱氢催化剂再生中的作用



氧化铝负载的Pt是轻质烷烃脱氢的主要工业催化剂之一。这种催化剂在反应过程中失去活性,焦炭的形成通常被认为是失活的原因。正如我们在这项研究中所示,碳沉积的数量和性质与活性丧失没有直接关系。相反,亚纳米 Pt 物质转变为较大的 Pt 纳米颗粒似乎是催化活性丧失的原因。令人惊奇的是,一部分Sn仍然以原子形式分散在废催化剂的氧化铝表面上,并有助于Pt的再分散。当氧化铝载体上没有 Sn 时,反应过程中形成的较大 Pt 纳米粒子在氧化再生过程中不会再分散。众所周知,在工业催化剂中添加锡作为促进剂有助于实现高丙烯选择性并最大限度地减少焦炭形成。这项工作表明,Sn 的一个重要作用是通过在氧化铝表面提供成核位点来帮助 Pt 再生。像差校正扫描透射电子显微镜通过展示促进剂元素(例如 Sn)在 γ-Al 2 O 3上 Pt 氧化再生中的作用,有助于对工业上重要的催化剂的操作特性提供独特的见解。
更新日期:2016-03-02
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