Platinum‐Rare Earth Alloy Electrocatalysts for the Oxygen Reduction Reaction: A Brief Overview

Campos-Roldán, Carlos A.; Jones, Deborah J.; Rozière, Jacqués; Cavalière, Sara

doi:10.1002/cctc.202200334

Cited by 20 publications

(13 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, the synthesis of nanoparticle Pt-REM alloys is challenging due to the highly negative standard redox potential of rare earth metals (far beyond the stability range of water) and their high oxophilicity, which favors formation of REM oxygen-containing species instead of alloys . Although recent synthesis approaches − have enabled the preparation of carbon-supported Pt-REM nanoalloys, their reported ORR mass activity (between 0.3 and 0.7 A mg Pt –1 ) − is far below that of unsupported 9 nm Pt x Y NPs (3.05 A mg Pt –1 ) or 8 nm Pt x Gd NPs (3.60 A mg Pt –1 ). Therefore, further understanding and optimization of Pt-REM/C nanoalloys are still needed.…”

Section: Introductionmentioning

confidence: 99%

Structure Dynamics of Carbon-Supported Platinum-Neodymium Nanoalloys during the Oxygen Reduction Reaction

et al. 2023

Self Cite

View full text Add to dashboard Cite

Platinum-rare earth nanoalloys have been predicted to be promising proton exchange membrane fuel cell (PEMFC) electrocatalysts for the cathodic oxygen reduction reaction (ORR). However, their implementation in PEMFCs is limited by the challenge of their preparation as carbon-supported nanostructures. Consequently, the practical structure–activity–stability trends for this class of nanoalloys remain largely unexplored. Herein, carbon-supported Pt–Nd nanoalloys as ORR electrocatalysts are described. The physical chemistry of selected electrocatalysts was extensively investigated by means of combined ex situ and operando techniques, which reveal the unique structural dynamics of Pt–Nd nanoalloys in a simulated PEMFC cathode environment. The experimental observations, supported by theoretical calculations, indicate that after initial significant structural modification in the early stage of operation, the ORR activity is mediated in the longer term by surface compressive strain rather than charge transfer between Pt and Nd. Such key operando structure–activity–stability relations underpin further optimization of carbon-supported Pt-rare earth nanoalloys as fuel cell cathode catalysts.

show abstract

Section: Introductionmentioning

confidence: 99%

Structure Dynamics of Carbon-Supported Platinum-Neodymium Nanoalloys during the Oxygen Reduction Reaction

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…Today, electrocatalysis plays a key role in achieving defossilization in minimizing carbon emission and hence in supporting the ambitious goals necessary to fight climate change. The electrochemical conversion of abundant small molecules like H 2 O, N 2 , O 2 , and CO 2 into chemical feedstocks or energy carriers using renewable electricity is considered a promising approach to the global supply of sustainable energy. − Consequently, the development of (electro)catalysts that can maximize the rates of reaction and minimize the overpotentials of these conversions is crucial for the large-scale industrialization of this green technology. , To enable a rational design of electrocatalysts, an in-depth understanding of the complex chemical occurrences at the electrochemical interface during a reaction (e.g., adsorption and desorption, charge and electron transfer, solvation and desolvation, and electrostatic interactions) is of high importance and the basis for engineering and optimizing electrocatalytic systems. ,,− …”

Section: Introductionmentioning

confidence: 99%

Operando Scanning Electrochemical Probe Microscopy during Electrocatalysis

et al. 2023

View full text Add to dashboard Cite

Scanning electrochemical probe microscopy (SEPM) techniques can disclose the local electrochemical reactivity of interfaces in single-entity and sub-entity studies. Operando SEPM measurements consist of using a SEPM tip to investigate the performance of electrocatalysts, while the reactivity of the interface is simultaneously modulated. This powerful combination can correlate electrochemical activity with changes in surface properties, e.g., topography and structure, as well as provide insight into reaction mechanisms. The focus of this review is to reveal the recent progress in local SEPM measurements of the catalytic activity of a surface toward the reduction and evolution of O2 and H2 and electrochemical conversion of CO2. The capabilities of SEPMs are showcased, and the possibility of coupling other techniques to SEPMs is presented. Emphasis is given to scanning electrochemical microscopy (SECM), scanning ion conductance microscopy (SICM), electrochemical scanning tunneling microscopy (EC-STM), and scanning electrochemical cell microscopy (SECCM).

show abstract

“…3 Thus, a large portion of PEMFC research has focused on lowering their cost by decreasing the amount of platinum in the cathode through alloying and microstructuring. 4 alloys remain as the catalyst benchmark for ORR in acidic media, but their thermodynamic instability in acidic conditions together with their scarcity and high cost demand alternative routes toward precious-metal catalyst eradication. One of the strategies that have emerged to eliminate costly precious metals is to switch to the alkaline analogue of the PEMFC, the anion exchange membrane fuel cell (AEMFC).…”

Section: ■ Introductionmentioning

confidence: 99%

“…However, the widespread commercialization of PEMFCs in automotive vehicles is currently impeded by their high cost and limited lifetime, which in turn is greatly attributed to the large amounts of platinum needed to catalyze the sluggish oxygen reduction reaction (ORR) kinetics in the cathode . Thus, a large portion of PEMFC research has focused on lowering their cost by decreasing the amount of platinum in the cathode through alloying and microstructuring. − So far, platinum and platinum alloys remain as the catalyst benchmark for ORR in acidic media, but their thermodynamic instability in acidic conditions together with their scarcity and high cost demand alternative routes toward precious-metal catalyst eradication.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tuning the Activity of Silver Alloys for the Oxygen Reduction Reaction in Alkaline Media

Montserrat‐Sisó

Wickman

2023

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

Ag-based catalysts have recently attracted much attention as potential candidates to substitute costly Pt-based electrocatalysts for the oxygen reduction reaction (ORR) in alkaline media. Although the electrocatalytic activity of Pt-based alloys is known to exhibit a strong dependence on their electronic structures, a relationship between electronic structure and the ORR mechanism in Ag-based alloys still remains to be elucidated. Herein, by means of physical vapor deposition, we prepare Ag binary thin films (CoAg, CuAg, AuAg, and FeAg) with well-controlled compositions as a tool to investigate the ORR mechanism on Ag surfaces. The bimetallic thin films are evaluated for their ORR performance in alkaline media, and their specific activity at 0.8 VRHE is shown to correlate with the Ag electronic structure. Even though all thin films show different responses to potential cycling, all bimetallic samples exhibit a surface Ag enrichment after ORR. It is shown that the ORR occurs through different mechanisms on these Ag-rich surfaces, which in turn is potential-dependent. Tafel slopes reveal faster ORR kinetics at low overpotentials on all surfaces, whereas only CuAg surpasses pure Ag at higher overpotentials. Moreover, despite their incomplete O2 reduction, CuAg and AuAg exhibit an overall superior ORR activity over pure Ag, with a more than 2-fold increase in specific activity at 0.8 VRHE attributed to enhancements originating from electronic effects and surface defects, respectively. Since the potential-dependent improved ORR mechanism observed for Ag bimetallic samples makes a rational design of Ag-based electrocatalysts difficult, these results aim to provide insights for a more tailored design of electrocatalysts by shedding light on the mechanisms through which the ORR kinetics are improved on Ag surfaces in alkaline media.

show abstract

Platinum‐Rare Earth Alloy Electrocatalysts for the Oxygen Reduction Reaction: A Brief Overview

Cited by 20 publications

References 55 publications

Structure Dynamics of Carbon-Supported Platinum-Neodymium Nanoalloys during the Oxygen Reduction Reaction

Structure Dynamics of Carbon-Supported Platinum-Neodymium Nanoalloys during the Oxygen Reduction Reaction

Operando Scanning Electrochemical Probe Microscopy during Electrocatalysis

Tuning the Activity of Silver Alloys for the Oxygen Reduction Reaction in Alkaline Media

Contact Info

Product

Resources

About