Advanced Electrodes for Solid Acid Fuel Cells by Platinum Deposition on CsH<sub>2</sub>PO<sub>4</sub>

Papandrew, Alexander B.; Chisholm, Calum R. I.; Elgammal, Ramez A.; Özer, Mustafa M.; Zečević, S.

doi:10.1021/cm101147y

Cited by 64 publications

(72 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We use the example of Cu ALD to illustrate the key concepts. Metal acetylacetonates are frequently used as the precursor for ALD, CVD, and atomic layer etching processes, [10][11][12][13] and copper(ii) acetylacetonate [Cu(acac) 2 ] has been mainly used in plasma assisted ALD processes to deposit metallic copper and copper oxide. For instance, Wu and Eisenbraun deposited copper thin film on a Ru substrate using Cu(acac) 2 and H 2 plasmas.…”

Section: Redox Adsorption Of Metal Precursormentioning

confidence: 99%

Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations

Elliott

Dey

Maimaiti

2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

Original citationElliott Reaction cycles for the atomic layer deposition (ALD) of metals are presented, based on the incomplete data that exist about their chemical mechanisms, particularly from density functional theory (DFT) calculations. ALD requires self-limiting adsorption of each precursor, which results from exhaustion of adsorbates from previous ALD pulses and possibly from inactivation of the substrate through adsorption itself. Where the latter reaction does not take place, an "abbreviated cycle" still gives self-limiting ALD, but at a much reduced rate of deposition. Here, for example, ALD growth rates are estimated for abbreviated cycles in H 2 -based ALD of metals. A wide variety of other processes for the ALD of metals are also outlined and then classified according to which a reagent supplies electrons for reduction of the metal. Detailed results on computing the mechanism of copper ALD by transmetallation are summarized and shown to be consistent with experimental growth rates. Potential routes to the ALD of other transition metals by using complexes of non-innocent diazadienyl ligands as metal sources are also evaluated using DFT. Published by AIP Publishing.

show abstract

Section: Redox Adsorption Of Metal Precursormentioning

confidence: 99%

Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations

Elliott

Dey

Maimaiti

2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…Solid acid fuel cells (SAFCs) are a relatively new class of fuel cells which employ the proton conductor cesium dihydrogen phosphate (CsH 2 PO 4 or CDP) as the electrolyte. This material undergoes a transition to a superprotonic phase at 228 °C, at which the conductivity rises by several orders of magnitude to ~ 10 -2 S/cm.…”

Section: Introductionmentioning

confidence: 99%

Atomic layer deposition of Pt@CsH2PO4 for the cathodes of solid acid fuel cells

Lim

Liu

Pandey

et al. 2018

Electrochimica Acta

Self Cite

View full text Add to dashboard Cite

Atomic layer deposition (ALD) has been used to apply continuous Pt films on powders of the solid acid CsH 2 PO 4 (CDP), in turn, used in the preparation of cathodes in solid acid fuel cells (SAFCs).The film deposition was carried out at 150 °C using trimethyl(methylcyclopentadienyl)platinum (MeCpPtMe 3 ) as the Pt source and ozone as the reactant for ligand removal. Chemical analysis showed a Pt growth rate of 0.09 ± 0.01 wt%/cycle subsequent to an initial nucleation delay of 84 ± 20 cycles. Electron microscopy revealed the contiguous nature of the films prepared using 200 or more cycles. The cathode overpotential (0.48 ± 0.02 V at a current density of 200 mA/cm 2 ) was independent of Pt deposition amount beyond the minimum required to achieve these continuous films. The cell electrochemical characteristics were moreover extremely stable with time, with the cathode overpotentials increasing by no more than 10 mV over a 100 h period of measurement. Thus, ALD holds promise as an effective tool in the preparation of SAFC cathodes with high activity and excellent stability.

show abstract

“…11,12,15 The solid precursors (Sigma-Aldrich) were mixed with as-received Vulcan XC-72R (Cabot) and thermally treated for 15 h in a water-N 2 atmosphere at 240…”

Section: Methodsmentioning

confidence: 99%

The Effect of Carbonate and pH on Hydrogen Oxidation and Oxygen Reduction on Pt-Based Electrocatalysts in Alkaline Media

John

Atkinson

Roy

et al. 2016

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

We investigated the performance of several carbon-supported Ru x Pt y electrocatalysts for their alkaline hydrogen oxidation and oxygen reduction performance in the presence of carbonate and compared their performance with monometallic, carbon-supported Pt. Our results indicate a strong dependence of HOR upon pH for the monometallic Pt catalysts (22 mV/pH) and a weak dependence upon pH for the Ru-containing electrocatalysts (3.7, 2.5, and 4.7 mV/pH on Ru 0.2 Pt 0.8 , Ru 0.4 Pt 0.6 , and Ru 0.8 Pt 0.2 , respectively). These results are consistent with our previous findings that illustrate a change in rds from electron transfer (on monometallic Pt) to dissociative hydrogen adsorption (on Ru x Pt y catalysts). Analysis of the kinetic currents to determine the rate-determining step via Tafel slope analysis provides additional data supporting this conclusion. There is no difference in the performance at comparable pH values in the presence or absence of carbonate on monometallic Pt indicating that water/hydroxide is the primary proton acceptor for alkaline HOR in 0.1 M KOH aqueous electrolyte. Finally, we observe no pH or carbonate dependence for the ORR on Ruthenium-platinum nanomaterials are currently the best performing alkaline hydrogen oxidation reaction (HOR) catalysts in fuel cells.1 Their improved activity vs. platinum has been realized through the understanding and application of ligand and bi-functional effects to reduce the metal-hydrogen, M-H, binding energy of Pt and to improve H ads reactivity with adsorbed hydroxyl groups, OH ads . [1][2][3][4] Hydrogen oxidation on Pt electrocatalyst is sensitive to pH because the rate-determining step is concerted electron/proton transfer (Volmer/Heyrovsky step).3,5 However, we have demonstrated on RuPt alloy catalysts that the rds changes to the pH-insensitive hydrogen dissociative adsorption (Tafel step). The impact of pH and carbonate on Ru-Pt alloy catalysts, consequently, remains unresolved for HOR in an alkaline environment.It is well documented that carbon dioxide in air partitions into the aqueous alkaline electrolyte at the cathode as carbonate and is purged at the anode during fuel cell operation.6-8 Carbonate has not been demonstrated to poison the anode catalyst; however, alkaline carbonate has been proposed as an active proton acceptor, 9 according to Eq. 1, competitive with hydroxide, Eq. 2.It has been suggested by some authors that because of water's ability to rapidly self-associate/dissociate that it is an active participant in the oxidation of H ads during alkaline hydrogen oxidation. Water is the major component of the electrolytic environment in both traditional, three-electrode electrochemical cells and in solid polymer electrolyte fuel cells. Consequently, if water is an active participant in the HOR, concentration effects should mask the contribution of carbonate. Resolving this question has important implications for modeling the alkaline fuel cell environment, as well as developing improved catalysts. * Electrochemical Society Active Member.*...

show abstract

Advanced Electrodes for Solid Acid Fuel Cells by Platinum Deposition on CsH₂PO₄

Cited by 64 publications

References 47 publications

Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations

Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations

Atomic layer deposition of Pt@CsH2PO4 for the cathodes of solid acid fuel cells

The Effect of Carbonate and pH on Hydrogen Oxidation and Oxygen Reduction on Pt-Based Electrocatalysts in Alkaline Media

Contact Info

Product

Resources

About

Advanced Electrodes for Solid Acid Fuel Cells by Platinum Deposition on CsH2PO4

Cited by 64 publications

References 47 publications

Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations

Classification of processes for the atomic layer deposition of metals based on mechanistic information from density functional theory calculations

Atomic layer deposition of Pt@CsH2PO4 for the cathodes of solid acid fuel cells

The Effect of Carbonate and pH on Hydrogen Oxidation and Oxygen Reduction on Pt-Based Electrocatalysts in Alkaline Media

Contact Info

Product

Resources

About

Advanced Electrodes for Solid Acid Fuel Cells by Platinum Deposition on CsH₂PO₄