Enhancement of Activity and Development of Low Pt Content Electrocatalysts for Oxygen Reduction Reaction in Acid Media

Molecules

Enrico Negro¹  Vito Di Noto¹  Keti Vezzù¹  Aldona Kostuch²  Beata Dembinska²  Anna Wadas²  Iwona A. Rutkowska²  Pawel J. Kulesza² 

[1] Department of Industrial Engineering, Università degli Studi di Padova, Via Marzolo 1, 35131 Padova, Italy;Faculty of Chemistry, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, Poland;

关键词: oxygen reduction;    electrocatalysis;    low Pt loading;    sub-stoichiometric metal oxides;    doping and functionalization of carbon carriers;    Pt alloys;   

DOI  :  10.3390/molecules26175147

来源: DOAJ

【 摘 要 】

Platinum is a main catalyst for the electroreduction of oxygen, a reaction of primary importance to the technology of low-temperature fuel cells. Due to the high cost of platinum, there is a need to significantly lower its loadings at interfaces. However, then O₂-reduction often proceeds at a less positive potential, and produces higher amounts of undesirable H₂O₂-intermediate. Hybrid supports, which utilize metal oxides (e.g., CeO₂, WO₃, Ta₂O₅, Nb₂O₅, and ZrO₂), stabilize Pt and carbon nanostructures and diminish their corrosion while exhibiting high activity toward the four-electron (most efficient) reduction in oxygen. Porosity of carbon supports facilitates dispersion and stability of Pt nanoparticles. Alternatively, the Pt-based bi- and multi-metallic catalysts, including PtM alloys or M-core/Pt-shell nanostructures, where M stands for certain transition metals (e.g., Au, Co, Cu, Ni, and Fe), can be considered. The catalytic efficiency depends on geometric (decrease in Pt–Pt bond distances) and electronic (increase in d-electron vacancy in Pt) factors, in addition to possible metal–support interactions and interfacial structural changes affecting adsorption and activation of O₂-molecules. Despite the stabilization of carbons, doping with heteroatoms, such as sulfur, nitrogen, phosphorus, and boron results in the formation of catalytically active centers. Thus, the useful catalysts are likely to be multi-component and multi-functional.

【 授权许可】

Unknown