High Durability of Pt3Sn/Graphene Electrocatalysts toward the Oxygen Reduction Reaction Studied with In Situ QEXAFS

Bing-Jian Su; Kuan-Wen Wang; Chung-Jen Tseng; Chih-Wen Pao; Jeng-Lung Chen; Kueih-Tzu Lu; Jin-Ming Chen

doi:10.1021/acsami.0c02415

High Durability of Pt₃Sn/Graphene Electrocatalysts toward the Oxygen Reduction Reaction Studied with In Situ QEXAFS

ACS Appl Mater Interfaces. 2020 Jun 3;12(22):24710-24716. doi: 10.1021/acsami.0c02415. Epub 2020 May 19.

Authors

Bing-Jian Su¹, Kuan-Wen Wang², Chung-Jen Tseng³, Chih-Wen Pao¹, Jeng-Lung Chen¹, Kueih-Tzu Lu¹, Jin-Ming Chen¹

Affiliations

¹ National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, ROC.
² Institute of Materials Science and Engineering, National Central University, Taoyuan City 32001, Taiwan, ROC.
³ Department of Mechanical Engineering, National Central University, Taoyuan City 32001, Taiwan, ROC.

PMID: 32374151
DOI: 10.1021/acsami.0c02415

Abstract

To prevent the corrosion of carbon and to enhance corrosion resistance, charge transfer, and mass transfer, graphene, which exhibits a high surface area and good conductivity, was used as an electrocatalyst support for a fuel cell. Pt₃Sn/G electrocatalysts for the oxygen reduction reaction (ORR) were prepared with alcohol reduction. The characterization of synthesized catalysts was analyzed according to the energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and extended X-ray absorption fine structure (EXAFS). The electrochemical performance was analyzed with cyclic-voltammetry (CV), linear sweep voltammetry (LSV), and accelerated degradation test (ADT) measurements. The Pt₃Sn/G electrocatalysts showed more positive onset potential and larger ORR mass activity than commercial Pt/C catalysts after 5000 cycles of ADT, indicating that in an acidic environment, Pt₃Sn/G is more chemically stable than Pt/C. Graphene has effective acid tolerance, is more stable against corrosion, and shows increased stability through preventing PtSn nanoparticles from detaching from the surface. According to the in situ quick EXAFS (QEXAFS) under a CV test to clarify the potential-dependent state of the Pt₃Sn/G electrocatalyst, the results show that the electrode surface is reproducible; there is no perceptible change in the oxidation state of the Pt₃Sn/G electrocatalyst. The radial distribution function (RDF) of the EXAFS spectra shows that the adsorption and desorption of H⁺ and OH^- cause no structural change in the Pt₃Sn crystallites. This work provides insight into the reaction mechanism of proton electroreduction and hydrogen adsorption on a Pt₃Sn/G electrocatalyst surface.

Keywords: Pt3Sn electrocatalysts; accelerated durability test; graphene; in situ QEXAFS; oxygen reduction reaction.