Mechanistic studies for depositing highly dispersed Pt nanoparticles on carbon by use of trimethyl(methylcyclopentadienyl)platinum(IV) reactions with O2 and H2

Lubers, Alia M.; Muhich, Christopher L.; Km, Anderson; Weimer, Alan W.

doi:10.1007/s11051-015-2982-9

Cited by 30 publications

(39 citation statements)

References 42 publications

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“…35,36 Adsorbed organic materials are, in fact, known to suppress the aggregation of supported metals by mediating their mobility, 10,25,37 especially on graphene surfaces. In addition, combustion reactions catalyzed by the metal itself can evolve heat and gas such as to generate local temperature and pressure fluctuations that can unpin and displace NPs as a whole, thus promoting sintering via NP diffusion and coalescence, 38−40 even at temperatures that would not otherwise provide the thermal budget for the onset of mobility.…”

mentioning

confidence: 99%

Understanding and Controlling the Aggregative Growth of Platinum Nanoparticles in Atomic Layer Deposition: An Avenue to Size Selection

Grillo

Bui

Moulijn

et al. 2017

J. Phys. Chem. Lett.

107

182

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We present an atomistic understanding of the evolution of the size distribution with temperature and number of cycles in atomic layer deposition (ALD) of Pt nanoparticles (NPs). Atomistic modeling of our experiments teaches us that the NPs grow mostly via NP diffusion and coalescence rather than through single-atom processes such as precursor chemisorption, atom attachment, and Ostwald ripening. In particular, our analysis shows that the NP aggregation takes place during the oxygen half-reaction and that the NP mobility exhibits a size- and temperature-dependent scaling. Finally, we show that contrary to what has been widely reported, in general, one cannot simply control the NP size by the number of cycles alone. Instead, while the amount of Pt deposited can be precisely controlled over a wide range of temperatures, ALD-like precision over the NP size requires low deposition temperatures (e.g., T < 100 °C) when growth is dominated by atom attachment.

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mentioning

confidence: 99%

Understanding and Controlling the Aggregative Growth of Platinum Nanoparticles in Atomic Layer Deposition: An Avenue to Size Selection

Grillo

Bui

Moulijn

et al. 2017

J. Phys. Chem. Lett.

107

182

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“…Platinum nanoparticles were deposited on unmodified or functionalized XC72R carbon support materials by ALD according to a previous report [18]. To summarize, XC72R was functionalized by refluxing in nitric acid for 9 hr.…”

Section: Ald Catalyst Synthesis and Materials Characterizationmentioning

confidence: 99%

“…Often, functional groups are placed on the substrate to facilitate deposition [15][16][17]. A previous study developed ALD as a large-scale method to produce PEMFC catalysts via combustion or hydrogenation chemistries, on plain or functionalized carbon [18]. In this report, catalysts grown from a hydrogen ALD chemistry were evaluated for promoting the oxygen reduction reaction (ORR).…”

Section: Introductionmentioning

confidence: 99%

Proton Exchange Membrane Fuel Cell Flooding Caused by Residual Functional Groups after Platinum Atomic Layer Deposition

Lubers

McNeary

Ludlow³

et al. 2017

Electrochimica Acta

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Proton exchange membrane fuel cell (PEMFC) catalysts manufactured using atomic layer deposition (ALD) on unmodified and functionalized carbon were compared to a commercial catalyst in half-and whole-cell tests. Half-cell tests showed the ALD catalyst performed better or comparable to a commercial catalyst. Conversely, whole-cell tests revealed flooding in the ALD catalyst produced on functionalized carbon. Residual functional groups had reduced the hydrophobicity, and rendered this catalyst impractical for use in whole-cell PEMFC applications. However, the ALD catalyst produced on unmodified carbon performed better than the commercial catalyst, which illustrates the power of ALD on appropriate catalyst supports.

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“…To deposit platinum [31], we placed 2 g of the functionalized XC72R in the fluidized bed reactor. See Fig.…”

Section: Pt Ald In a Fluidized Bedmentioning

confidence: 99%

Electrochemical hydrogen pumping using a platinum catalyst made in a fluidized bed via atomic layer deposition

Lubers

Drake

Ludlow³

et al. 2016

Powder Technology

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a b s t r a c t a r t i c l e i n f o Available online xxxx Keywords: Platinum Catalysts Hydrogen pumping Fluidized bed Fluidization Atomic layer depositionPlatinum nanoparticle catalysts for electrochemical hydrogen pumping were synthesized on a functionalized powder carbon substrate (XC72R) using atomic layer deposition (ALD) in a fluidized bed reactor (FBR). Trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe 3 ) was used as the reagent for platinum delivery. Following deposition, MeCpPtMe 3 ligands were combusted or hydrogenated to yield platinum on the XC72R surface. Reactions throughout the ALD cycle were monitored using mass spectrometry and IR spectroscopy to clarify the deposition chemistry. The resultant platinum catalysts were compared to commercial products in hydrogen pumping tests. Hydrogenation made finer, more dispersed, platinum nanoparticles that performed similarly to their commercial equivalent when pumping hydrogen. Conversely, oxygenation made a coarser catalyst that underperformed its commercial equivalent. Thus, altering chemistries shows potential for improving ALD catalyst performance.

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Mechanistic studies for depositing highly dispersed Pt nanoparticles on carbon by use of trimethyl(methylcyclopentadienyl)platinum(IV) reactions with O2 and H2

Cited by 30 publications

References 42 publications

Understanding and Controlling the Aggregative Growth of Platinum Nanoparticles in Atomic Layer Deposition: An Avenue to Size Selection

Understanding and Controlling the Aggregative Growth of Platinum Nanoparticles in Atomic Layer Deposition: An Avenue to Size Selection

Proton Exchange Membrane Fuel Cell Flooding Caused by Residual Functional Groups after Platinum Atomic Layer Deposition

Electrochemical hydrogen pumping using a platinum catalyst made in a fluidized bed via atomic layer deposition

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