(Invited) Catalytic Surface Reactions during Nucleation and Growth of Atomic Layer Deposition of Noble Metals: A Case Study for Platinum

Mackus, Adriaan J. M.; Bol, Ageeth A.; Kessels, Wmm Erwin

doi:10.1149/05810.0183ecst

Cited by 6 publications

(3 citation statements)

References 43 publications

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“…For Pt ALD, the reaction mechanism of film growth is strongly dependent on catalytic surface reactions [38]. During the MeCpPtMe 3 pulse of the ALD process, the ligands of the MeCpPtMe 3 precursor undergo dehydrogenation reactions on the catalytic Pt surface, [20] which leads to a surface covered with carbonaceous species [39].…”

Section: Catalytic Surface Reactions During Nanoparticle Growthmentioning

confidence: 99%

Atomic layer deposition of Pd and Pt nanoparticles for catalysis: on the mechanisms of nanoparticle formation

et al. 2015

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The deposition of Pd and Pt nanoparticles by atomic layer deposition (ALD) has been studied extensively in recent years for the synthesis of nanoparticles for catalysis. For these applications, it is essential to synthesize nanoparticles with well-defined sizes and a high density on large-surface-area supports. Although the potential of ALD for synthesizing active nanocatalysts for various chemical reactions has been demonstrated, insight into how to control the nanoparticle properties (i.e. size, composition) by choosing suitable processing conditions is lacking. Furthermore, there is little understanding of the reaction mechanisms during the nucleation stage of metal ALD. In this work, nanoparticles synthesized with four different ALD processes (two for Pd and two for Pt) were extensively studied by transmission electron spectroscopy. Using these datasets as a starting point, the growth characteristics and reaction mechanisms of Pd and Pt ALD relevant for the synthesis of nanoparticles are discussed. The results reveal that ALD allows for the preparation of particles with control of the particle size, although it is also shown that the particle size distribution is strongly dependent on the processing conditions. Moreover, this paper discusses the opportunities and limitations of the use of ALD in the synthesis of nanocatalysts.

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Section: Catalytic Surface Reactions During Nanoparticle Growthmentioning

confidence: 99%

Atomic layer deposition of Pd and Pt nanoparticles for catalysis: on the mechanisms of nanoparticle formation

et al. 2015

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“…Most of these processes use molecular oxygen (O 2 ), a reactant that is otherwise usually found to be inert under typical ALD conditions, to combust ligands of the metal precursors. Successful use of molecular oxygen relies on its dissociative adsorption on catalytically active platinum-metal surfaces, transforming it into the much more reactive atomic form. , Most of the ALD studies on platinum metals have concerned platinum and ruthenium (see ref for a thorough review on platinum-metal ALD), whereas iridium has gained less attention despite its attractive properties such as high melting point, high density, low electrical resistivity, and excellent chemical resistance . Previously reported ALD processes of Ir most often use O 2 as a reactant with Ir(acac) 3 , , (EtCp)Ir(COD), or (MeCp)Ir(CHD) at temperatures above 200 °C, whereas consecutive O 3 and H 2 pulses can be used to deposit Ir at temperatures below 200 °C. , Plasma-enhanced ALD processes using H 2 plasma, NH 3 plasma, or mixed O 2 –H 2 plasma have also been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Atomic Layer Deposition of Iridium Thin Films Using Sequential Oxygen and Hydrogen Pulses

et al. 2016

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Atomic layer deposition (ALD) is an advanced thin-film deposition method based on self-limiting surface reactions that allows for the controlled deposition of conformal, high-quality thin films of various materials. In this study, we aimed to explore how modifying the deposition chemistry affects the growth and properties of iridium films. We demonstrated a new ALD process using sequential pulses of iridium acetylacetonate [Ir(acac)3], oxygen (O2), and hydrogen (H2) and compared this to the established Ir(acac)3 + O2 process in the wide temperature range of 200–350 °C. A reaction scheme is proposed to explain how both oxygen and hydrogen affect the film growth. Comprehensive information on film properties was obtained for both processes. In particular, the strong (111) texture seen in this study has not been reported before for ALD iridium films. Changes in film properties, especially lowered resistivity, stronger (111) texture, and faster nucleation compared to the Ir(acac)3 + O2 process, should motivate further studies on O2 + H2 processes of platinum metals.

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“…As shown in Figure 2B, during precursor pulse, the [50] and Medlin et al [51] suggested that the OH group on metal oxides play a significant role in the nucleation of Pt atoms. There are several processes that may play a role in the nucleation stage ( Figure 3A) [52,53]: (i) atom diffusion; (ii) particle ripening/Ostwald ripening and (iii) spillover of species from the NPs. Pt nanoparticle formed via an island growth mechanism (Volmer-Weber mechanism) during the initial stages of ALD process, followed by island coalescence and formation of a continuous thin film as shown in Figure 3B.…”

Section: The Mechanism Of Ald Pt Processmentioning

confidence: 99%

Electrocatalysts by atomic layer deposition for fuel cell applications

Cheng

Shao

et al. 2016

Nano Energy

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Fuel cells are a promising technology solution for reliable and clean energy because they offer high energy conversion efficiency and low emission of pollutants. However, high cost and insufficient durability are considerable challenges for widespread adoption of proton exchange membrane fuel cells (PEMFCs) in practical applications. Current PEMFCs catalysts have been identified as major contributors to both the high cost and limited durability. Atomic layer deposition (ALD) is emerging as a powerful technique for solving these problems due to its exclusive advantages over other methods. In this review, we summarize recent developments of ALD in PEMFCs with a focus on design of materials for improved catalyst activity and durability. New research directions and future trends have also been discussed.

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(Invited) Catalytic Surface Reactions during Nucleation and Growth of Atomic Layer Deposition of Noble Metals: A Case Study for Platinum

Cited by 6 publications

References 43 publications

Atomic layer deposition of Pd and Pt nanoparticles for catalysis: on the mechanisms of nanoparticle formation

Atomic layer deposition of Pd and Pt nanoparticles for catalysis: on the mechanisms of nanoparticle formation

Atomic Layer Deposition of Iridium Thin Films Using Sequential Oxygen and Hydrogen Pulses

Electrocatalysts by atomic layer deposition for fuel cell applications

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