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Improving the ORR performance by enhancing the Pt oxidation resistance

DOI: 10.1016/j.jcat.2022.10.025 DOI Help

Authors: Ruoyu Xu (University College London (UCL)) , Liqun Kang (University College London (UCL)) , Konstantinos G. Papanikolaou (University College London) , Bolun Wang (University College London) , Sushila Marlow (University College London) , Qian He (National University of Singapore) , Peng Zhang (Dalhousie University) , Jianfang Wang (The Chinese University of Hong Kong) , Dan J. I. Brett (University College London) , Michail Stamatakis (University College London) , Feng Ryan Wang (University College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Catalysis , VOL 44

State: Published (Approved)
Published: November 2022
Diamond Proposal Number(s): 20643 , 19318 , 19246 , 19072 , 20629

Open Access Open Access

Abstract: Proton exchange membrane fuel cells require oxygen reduction catalysts with high activity and stability. Pt based alloy materials are most widely applied ORR catalyst due to its high intrinsic activity, but usually suffer from rapid deactivation as a result of particle agglomeration, detachment, Ostwald ripening and/or Pt dissolution. Here we investigate the degradation of the PdPt alloys via in situ X-ray absorption fine structure, Δμ analysis, identical location-electron microscopy and DFT calculations. We conclude that the origin of high activity and stability of the PdPt catalyst stems from the oxidation resistance of metallic Pt, forming mainly surface adsorbed O species at high potentials. Two stage degradation process are observed, showing an evolution of dynamic surface dependent ORR performance along with the deactivation process. The careful design of Pt alloy structure leads to controlled surface oxygen behaviours. This opens a new way to increase the lifespan of fuel cells and improve the Pt utilization efficiency.

Journal Keywords: Oxygen Reduction Reaction; Electron microscopy; X-ray absorption spectroscopy; Density functional calculations

Diamond Keywords: Fuel Cells; Alloys

Subject Areas: Chemistry, Materials, Energy

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: B18-Core EXAFS , E01-JEM ARM 200CF

Other Facilities: BL01B1 at SPring-8

Added On: 09/11/2022 10:14

Documents:
1-s2.0-S0021951722004456-main.pdf

Discipline Tags:

Energy Storage Energy Physical Chemistry Catalysis Energy Materials Chemistry Materials Science Metallurgy

Technical Tags:

Microscopy Spectroscopy Electron Microscopy (EM) X-ray Absorption Spectroscopy (XAS) Extended X-ray Absorption Fine Structure (EXAFS) X-ray Absorption Near Edge Structure (XANES) Scanning Transmission Electron Microscopy (STEM)