Addressing stability challenges of using bimetallic electrocatalysts: the case of gold–palladium nanoalloys

Pizzutilo, Enrico; Geiger, Simon; Baldizzone, Claudio; Mingers, Andrea Maria; Hutchings, Graham J.; Mayrhofer, Karl Johann Jakob; Cherevko, Serhiy

doi:10.1039/c7cy00291b

Cited by 38 publications

(49 citation statements)

References 83 publications

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“…GC/Zn‐MOF electrode does not show any peak in the selected potential window (0.2 to 1.1 V). However, the GC/Au@Zn‐MOF shows a pair of peaks which represent the formation of surface gold oxide and its reduction . This clearly shows the successful incorporation of Au NPs into Zn‐MOF and its viability for the electrocatalytic reactions.…”

Section: Resultsmentioning

confidence: 99%

Gold Nanoparticles Incorporated in a Zinc‐Based Metal‐Organic Framework as Multifunctional Catalyst for the Oxygen Reduction and Hydrogen Evolution Reactions

et al. 2018

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Successful synthesis of gold nanoparticles incorporated in a zinc‐based metal‐organic framework (Au@Zn‐MOF) is reported in this paper. The synthesis of Au@Zn‐MOF is confirmed by UV‐Vis, FT‐IR and X‐ray photoelectron spectroscopy (XPS) studies. The Au@Zn‐MOF catalyst demonstrates electrocatalytic activity towards the oxygen reduction reaction (ORR) and the hydrogen evolution reaction (HER). The relative catalytic performance of Au@Zn‐MOF towards ORR and HER has been studied under acidic condition. ORR proceeds via a two electron and two proton mechanism with hydrogen peroxide as the end product, while HER follows the Volmer mechanism i. e., adsorption of H+ on the catalyst's active sites. Au@Zn‐MOF exhibits an ORR onset potential of 0.45 V (vs. RHE) with two different Tafel slopes, −93 and −103.6 mV in acidic solution. Further, an excellent catalytic activity is observed for HER with an onset potential of 0.02 V (vs. RHE) and a Tafel slope of 87 mV in N2 saturated 0.1 M HClO4 solution. However, in O2 saturated 0.1 M HClO4 solution, a HER onset potential of 0.04 V (vs. RHE) is observed with two different Tafel slopes, 610 and 220 mV. The value of Tafel slopes in the presence of O2 advocates the diminution of the ORR activity because of the HER. Thus, Tafel slope values of HER and ORR suggest that protons and O2 compete to reach the electrode surface for getting reduced.

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Section: Resultsmentioning

confidence: 99%

Gold Nanoparticles Incorporated in a Zinc‐Based Metal‐Organic Framework as Multifunctional Catalyst for the Oxygen Reduction and Hydrogen Evolution Reactions

et al. 2018

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“…3 RESULTS AND DISCUSSION The AuPd/C employed in this study, as well as the reference Au/C and Pd/C, are synthesized through a sol-immobilization method and have a nominal metal loading of 10wt%. In our previous publication, we characterized the dissolution behavior of AuPd particles immobilized directly onto an electrode as a model system 30,31 . In particular, we showed that the difference in Pd and Au dissolution onset potentials (ca.…”

Section: Tem Characterizationmentioning

confidence: 99%

“…Evidence of the surface change induced by dissolution is supported by the CVs recorded in Ar saturated electrolytes ( Figure 1b). Indeed, once the upper potential limit (UPL) is sufficiently high (above Au oxide formation 30 , ca. 1.5 VRHE) two distinct peaks are observable on the reverse scan: Pd oxide and Au oxide reduction.…”

Section: Tem Characterizationmentioning

confidence: 99%

Gold–Palladium Bimetallic Catalyst Stability: Consequences for Hydrogen Peroxide Selectivity

et al. 2017

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During application, electrocatalysts are exposed to harsh electrochemical conditions, which can induce degradation. This work addresses the degradation of AuPd bimetallic catalysts used for the electrocatalytic production of hydrogen peroxide (H2O2) by oxygen reduction reaction (ORR). Potential dependent changes in the AuPd surface composition occur because the two metals have different dissolution onset potentials, resulting in catalyst dealloying. Using the scanning flow cell (SFC) with an inductively coupled plasma mass spectrometer (ICPMS), the simultaneous Pd and/or Au dissolution can be observed. Thereafter, three accelerated degradation protocols (ADPs), simulating different dissolution regimes, are employed to study the catalyst structure degradation on the nanoscale with identical location (IL-) TEM. When only Pd or both Au and Pd dissolve, the composition changes rapidly and the surface becomes enriched with Au as observed by cyclic voltammetry and elemental mapping. Such changes are mirrored by the evolution of electrocatalytic performances towards the H2O2 production. Our experimental findings are finally summarized in a dissolution/structure/selectivity mechanism providing a clear picture of the degradation of bimetallic catalyst used for H2O2 synthesis.

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“…For example, the introduction of a secondary metal (e.g., Au, Ir, Cu, etc.) at a certain concentration to form alloys or intermetallics can improve not only the activity but also the chemical stability of the Pd‐based catalysts through ensemble and electronic effects . The improvement of thermal and mechanical stabilities can be achieved through the fabrication of Pd‐based nanoarchitectures with higher dimensions (1D, 2D, and 3D), since they have lower vulnerability to dissolution, the Ostwald ripening, and aggregation during the reactions compared to 0D nanoparticles .…”

Section: Introductionmentioning

confidence: 99%

Chemical Design of Palladium‐Based Nanoarchitectures for Catalytic Applications

Iqbal

Kaneti

Kim

et al. 2019

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Palladium (Pd) plays an important role in numerous catalytic reactions, such as methanol and ethanol oxidation, oxygen reduction, hydrogenation, coupling reactions, and carbon monoxide oxidation. Creating Pd‐based nanoarchitectures with increased active surface sites, higher density of low‐coordinated atoms, and maximized surface coverage for the reactants is important. To address the limitations of pure Pd, various Pd‐based nanoarchitectures, including alloys, intermetallics, and supported Pd nanomaterials, have been fabricated by combining Pd with other elements with similar or higher catalytic activity for many catalytic reactions. Herein, recent advances in the preparation of Pd‐based nanoarchitectures through solution‐phase chemical reduction and electrochemical deposition methods are summarized. Finally, the trend and future outlook in the development of Pd nanocatalysts toward practical catalytic applications are discussed.

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Addressing stability challenges of using bimetallic electrocatalysts: the case of gold–palladium nanoalloys

Abstract: Studying changes in surface composition of bimetallic (AuPd) catalysts under dealloying is of key importance for predicting their stability during application.

Cited by 38 publications

References 83 publications

Gold Nanoparticles Incorporated in a Zinc‐Based Metal‐Organic Framework as Multifunctional Catalyst for the Oxygen Reduction and Hydrogen Evolution Reactions

Gold Nanoparticles Incorporated in a Zinc‐Based Metal‐Organic Framework as Multifunctional Catalyst for the Oxygen Reduction and Hydrogen Evolution Reactions

Gold–Palladium Bimetallic Catalyst Stability: Consequences for Hydrogen Peroxide Selectivity

Chemical Design of Palladium‐Based Nanoarchitectures for Catalytic Applications

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