Investigating anomalous growth of platinum particles during accelerated aging of diesel oxidation catalysts
Investigating anomalous growth of platinum particles during accelerated aging of diesel oxidation catalysts
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DOI：
10.1016/j.apcatb.2020.118598
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发表时间：
2020-06
影响因子：
22.1
通讯作者：
Deepak Kunwar;Cristhian Carrillo;Haifeng Xiong;E. Peterson;A. DeLaRiva;Arnab Ghosh;Gongshin Qi;Ming-Mei Yang;Michelle H. Wiebenga;S. Oh;Wei Li;A. Datye
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文献类型：
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作者：
Deepak Kunwar;Cristhian Carrillo;Haifeng Xiong;E. Peterson;A. DeLaRiva;Arnab Ghosh;Gongshin Qi;Ming-Mei Yang;Michelle H. Wiebenga;S. Oh;Wei Li;A. Datye
当Pt催化剂在空气中在800 °C下老化时，我们看到Pt颗粒尺寸显著增长。老化催化剂中的粒度分布通常是双峰的，一些非常大的颗粒与较小的颗粒共存。在这里，我们调查这些异常的颗粒尺寸分布的起源，并将它们与氧化条件下的气相传输的PtO2。我们的研究结果表明，PtO2从催化剂排放到汽相可能是一个原因，在高温老化过程中观察到的Pt颗粒的异常生长。我们发现，支持，如二氧化铈，可以捕获Pt离子引起的气相传输的抑制，而氧化铝和MgAl2O4尖晶石支持是无法捕获的Pt离子，导致异常大的Pt颗粒的形成。
When Pt catalysts are aged in air at 800 °C, we see significant growth of Pt particle sizes. The particle size distributions in the aged catalysts are usually bimodal, with some very large particles coexisting with smaller particles. Here we investigate the origins of these anomalous particle size distributions and relate them to the vapor phase transport of PtO2under oxidizing conditions. Our results suggest that the emission of PtO2from the catalyst into vapor phase could be a cause for the anomalous growth of Pt particles observed during high temperature aging. We show that supports such as ceria that can trap Pt ions cause a suppression of vapor phase transport, while the alumina and the MgAl2O4spinel supports are unable to trap the Pt ions leading to the formation of abnormally large Pt particles.