Atomic Layer Deposition Overcoating Improves Catalyst Selectivity and Longevity in Propane Dehydrogenation,ACS Catalysis

当前位置： X-MOL 学术 › ACS Catal. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Atomic Layer Deposition Overcoating Improves Catalyst Selectivity and Longevity in Propane Dehydrogenation
ACS Catalysis ( IF 11.3 ) Pub Date : 2020-11-16 , DOI: 10.1021/acscatal.0c03391
Zheng Lu ₁ , Ryon W. Tracy ₂ , M. Leigh Abrams ₃ , Natalie L. Nicholls ₃ , Paul T. Barger ₃ , Tao Li _{4,

5} , Peter C. Stair _{1,

6} , Arrelaine A. Dameron ₂ , Christopher P. Nicholas ₃ , Christopher L. Marshall ₁

Affiliation

Propylene, a precursor for commodity chemicals and plastics, is produced by propane dehydrogenation (PDH). An increase in PDH yield via added catalyst activity, lifetime, or selectivity represents significant energy and economic savings. Using Pt dispersed on Al₂O₃ extrudate supports as a commercially relevant model system, we demonstrate that atomic layer deposition (ALD) metal oxide overcoats, used to tailor metal-active sites, can increase PDH yield and selectivity. We investigate the interplay of Pt loading, ALD overcoat thickness, and Al₂O₃ support surface area on PDH activity, selectivity, and catalyst stability to show that applying a 6–8 Å thick layer of Al₂O₃ on low-surface area Al₂O₃ supports of ∼90 m²/g surface area yields the optimal combination of stability and activity, while increasing propylene selectivity from 91 to 96%. Increased stability upon steaming deactivation occurs because the Al₂O₃ overcoat prevents the Pt nanoparticles from sintering. We speculate that the ALD overcoat selectively binds to the undercoordinated sites on the Pt nanoparticles, while leaving the more selective terrace sites available for dehydrogenation.

中文翻译：

原子层沉积外涂层可改善丙烷脱氢中的催化剂选择性和寿命

丙烯是商品化学品和塑料的前体，是通过丙烷脱氢（PDH）生产的。通过增加催化剂的活性，寿命或选择性增加PDH的产量代表了可观的能源和经济节约。使用分散在Al ₂ O ₃挤出物载体上的Pt作为与商业相关的模型系统，我们证明了用于定制金属活性位的原子层沉积（ALD）金属氧化物外涂层可以提高PDH的产率和选择性。我们研究了Pt负载，ALD涂层厚度和Al ₂ O ₃载体表面积对PDH活性，选择性和催化剂稳定性之间的相互作用，以显示施加6-8Å厚的Al ₂ O ₃层在约90 m ² / g表面积的低表面积Al ₂ O ₃载体上，可获得稳定性和活性的最佳组合，同时丙烯的选择性从91％提高到96％。由于Al ₂ O ₃覆盖层阻止了Pt纳米颗粒的烧结，因此发生了蒸汽失活时增加的稳定性。我们推测，ALD外涂层选择性地结合到Pt纳米颗粒上的配位不足的位点上，而留下更多的选择性平台位点可用于脱氢。

更新日期：2020-12-04

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南