Volatilization of Platinum.

Hulett, G. A.; Berger, Harvey W

doi:10.1021/ja02001a012

Cited by 5 publications

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“…A notable feature of Pt is the high vapor pressure of Pt oxide which can cause a loss of weight in Pt crucibles, and cause massive restructuring of Pt foils heated in air [19,20]. But Pd on the other hand forms a stable oxide (PdO) in air that has negligible vapor pressure ($3 orders of magnitude less than that of Pd metal) [21].…”

Section: Introductionmentioning

confidence: 99%

Relating adatom emission to improved durability of Pt–Pd diesel oxidation catalysts

Johns

Goeke

Ashbacher

et al. 2015

Journal of Catalysis

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a b s t r a c tSintering of nanoparticles is an important contributor to loss of activity in heterogeneous catalysts, such as those used for controlling harmful emissions from automobiles. But mechanistic details, such as the rates of atom emission or the nature of the mobile species, remain poorly understood. Herein we report a novel approach that allows direct measurement of atom emission from nanoparticles. We use model catalyst samples and a novel reactor that allows the same region of the sample to be observed after short-term heat treatments (seconds) under conditions relevant to diesel oxidation catalysts (DOCs). Monometallic Pd is very stable and does not sinter when heated in air (T 6 800°C). Pt sinters readily in air, and at high temperatures (P800°C) mobile Pt species emitted to the vapor phase cause the formation of large, faceted particles. In Pt-Pd nanoparticles, Pd slows the rate of emission of atoms to the vapor phase due to the formation of an alloy. However, the role of Pd in Pt DOCs in air is quite complex: at low temperatures, Pt enhances the rate of Pd sintering (which otherwise would be stable as an oxide), while at higher temperature Pd helps to slow the rate of Pt sintering. DFT calculations show that the barrier for atom emission to the vapor phase is much greater than the barrier for emitting atoms to the support. Hence, vapor-phase transport becomes significant only at high temperatures while diffusion of adatoms on the support dominates at lower temperatures.

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Section: Introductionmentioning

confidence: 99%

Relating adatom emission to improved durability of Pt–Pd diesel oxidation catalysts

Johns

Goeke

Ashbacher

et al. 2015

Journal of Catalysis

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Revision der Atomgewichte von Natrium und Chlor

Richards

Wells

1905

Z. Anorg. Chem.

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S. 56. – Wage und Gewichte. S. 63. –Herstellung reiner Materialien: S. 65. Wasser; Chlorwasserstoffsäure; Natriumchlorid; Silber; Kalk; Utensilien. – Die Löslichkeit von Silberchlorid. S. 82. – Die Okklusion von gelösten Substanzen durch Silberchlorid. S. 88. – Das Verhältnis von Natriumchlorid zu Silberchlorid. S. 93. – Das Verhältnis von Natriumchlorid zu Silber. S. 105. – Das Schmelzen von Natriumchlorid im Vakuum. S. 117. – Synthese des Silberchlorids. S. 119. – Die neuen Atomgewichte von Natrium und Chlor und ihr Einfluss auf andere Atomgewichte. S. 131. – Zusammenfassung. S. 133.

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Kolloidwissenschaft, Elektrotechnik und heterogene Katalyse

Ostwald¹

1930

Kolloidchem Beih

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Volatilization of Platinum.

Cited by 5 publications

References 0 publications

Relating adatom emission to improved durability of Pt–Pd diesel oxidation catalysts

Relating adatom emission to improved durability of Pt–Pd diesel oxidation catalysts

Revision der Atomgewichte von Natrium und Chlor

Kolloidwissenschaft, Elektrotechnik und heterogene Katalyse

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