Bottom-Up Fabrication of Oxygen Reduction Electrodes with Atomic Layer Deposition for High-Power-Density PEMFCs

Dull, Samuel; Xu, Shicheng; Goh, Timothy; Lee, Dong Un; Higgins, Drew; Orazov, Marat; Koshy, David M.; Vullum, Per Erik; Kirsch, Sebastian; Huebner, Gerold; Torgersen, Jan; Jaramillo, Thomas F.; Prinz, Fritz B.

doi:10.1016/j.xcrp.2020.100297

Cited by 10 publications

(19 citation statements)

References 52 publications

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“…[4] Electrochemical devices that utilize oxygen (O 2 ) as a feedstock, e. g. fuel cells and metal-air batteries, rely on electrocatalysts for the oxygen reduction reaction (ORR) for their overall performance. [5][6] Commercially, ORR electrocatalysts have been limited to precious metals in acidic electrolytes, typically platinum (Pt)-based materials, owing to their high ORR activity, 4e À selectivity, and stability compared to other materials. [5,7] ORR catalysis in alkaline environments shows promise as it enables the use of non-precious metal catalysts owing to less demanding stability requirements and improved oxygen adsorption at high pH's.…”

Section: Introductionmentioning

confidence: 99%

Probing the Effects of Acid Electrolyte Anions on Electrocatalyst Activity and Selectivity for the Oxygen Reduction Reaction

et al. 2021

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The local microenvironment at the electrode-electrolyte interface plays an important role in electrocatalytic performance. Herein, we investigate the effect of acid electrolyte anion identity on the oxygen reduction reaction (ORR) activity and selectivity of smooth Ag and Pd catalyst thin films. Cyclic voltammetry in perchloric, nitric, sulfuric, phosphoric, hydrochloric, and hydrobromic acid, at pH 1, reveals that Ag ORR activity trends as follows: HClO 4 > HNO 3 > H 2 SO 4 > H 3 PO 4 > HCl @ HBr, while Pd ORR activity trends as: HClO 4 > H 2 SO 4 > HNO 3 > H 3 PO 4 > HCl @ HBr. Moreover, rotating-ring-disk-electrode selectivity measurements demonstrate enhanced 4e À selectivity on both Ag and Pd, by up to 35 %H 2 O 2 and 10 %H 2 O 2 respectively, in HNO 3 compared to in HClO 4 . Relating physicsbased modeling and experimental results, we postulate that ORR performance depends greatly on anion-related phenomena in the double layer, for instance competitive adsorption and non-covalent interactions.

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Section: Introductionmentioning

confidence: 99%

Probing the Effects of Acid Electrolyte Anions on Electrocatalyst Activity and Selectivity for the Oxygen Reduction Reaction

et al. 2021

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“…The GC disks were cleaned sequentially in aqua regia and acetone, and the GDEs were prepared by filtration of KetjenBlack EC300J carbon onto Sigracet 22BB. 11 Prior to catalyst deposition, both substrates were treated for 10 min with oxygen plasma (Harrick PDC-001, 30 W). After the relevant syntheses (detailed below), the GDEs were impregnated with an aqueous 0.5 wt % 1100 EW Nafion dispersion (∼7.8% alcohols) prior to testing.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…The resulting Pt nanoparticles are roughly 3 nm in diameter. 11 PtZnALD250. For the ALD-based Zn alloy, ZnO was first grown on the Pt nanoparticles at 180 °C using alternating 0.1 s doses of diethyl zinc (DEZ) and H 2 O.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Testing was performed in a Scribner 840 system using a Greenlight 50 cm 2 cell fixture with serpentine flow fields compressed to 4 bar. 11 Throughout the entire testing sequence, 500 sccm H 2 (99.999%, Praxair) was flown through the anode. To break in the MEA, a cathode recovery protocol was performed by maintaining a 0.1 V bias for 4 h in air (1000 sccm) at 40 °C and 150% relative humidity (RH).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…To break in the MEA, a cathode recovery protocol was performed by maintaining a 0.1 V bias for 4 h in air (1000 sccm) at 40 °C and 150% relative humidity (RH). 11 All subsequent electrochemical measurements were carried out at 80 °C, 100% RH, and 1.5 bar absolute pressure, unless stated otherwise. To quantify the ECSA, a cyclic voltammogram (CV) between 0.06 and 0.6 V (50 mV/s) was measured after purging the cathode with Ar.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Alloyed Pt–Zn Oxygen Reduction Catalysts for Proton Exchange Membrane Fuel Cells

Dull

Vinogradova

et al. 2022

ACS Appl. Energy Mater.

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Better oxygen reduction catalysts are needed to appreciably increase the efficiency of proton exchange membrane fuel cells. In this work, high-activity Pt−Zn alloy catalysts were prepared using two distinct synthetic approaches. The first�where Zn was introduced to Pt nanoparticles via atomic layer deposition�led to a 30% increase in Pt-mass-normalized fuel cell activity. Density functional theory calculations elucidated the origin of this enhancement and motivated the preparation of an alloy with increased Zn content. To this end, a fabrication technique leveraging Zn electroplating was employed to prototype a second Pt−Zn alloy with a rotating disk electrode (RDE). The higher-dosed structure (∼19 at. % Zn) delivered exemplary activity (MA = ∼3 A/mg Pt ), but the synthetic approach was not amenable to membrane electrode assembly (MEA) fabrication. An Arrhenius analysis was carried out to project the hypothetical catalytic enhancement under fuel cell operating conditions. This exercise introduced a discussion on the reduced activity observed in MEAs relative to the benchtop RDE setups used more ubiquitously for catalyst evaluation.

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Hydrocarbon Ionomeric Binders for Fuel Cells and Electrolyzers

Kim

2023

Advanced Science

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Ionomeric binders in catalyst layers, abbreviated as ionomers, play an essential role in the performance of polymer–electrolyte membrane fuel cells and electrolyzers. Due to environmental issues associated with perfluoroalkyl substances, alternative hydrocarbon ionomers have drawn substantial attention over the past few years. This review surveys literature to discuss ionomer requirements for the electrodes of fuel cells and electrolyzers, highlighting design principles of hydrocarbon ionomers to guide the development of advanced hydrocarbon ionomers.

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Bottom-Up Fabrication of Oxygen Reduction Electrodes with Atomic Layer Deposition for High-Power-Density PEMFCs

Cited by 10 publications

References 52 publications

Probing the Effects of Acid Electrolyte Anions on Electrocatalyst Activity and Selectivity for the Oxygen Reduction Reaction

Probing the Effects of Acid Electrolyte Anions on Electrocatalyst Activity and Selectivity for the Oxygen Reduction Reaction

Alloyed Pt–Zn Oxygen Reduction Catalysts for Proton Exchange Membrane Fuel Cells

Hydrocarbon Ionomeric Binders for Fuel Cells and Electrolyzers

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