• 文献标题:   Tailored Electron Transfer Pathways in Au-core/Pt-shell-Graphene Nanocatalysts for Fuel Cells
  • 文献类型:   Article
  • 作  者:   SESELJ N, ENGELBREKT C, DING Y, HJULER HA, ULSTRUP J, ZHANG JD
  • 作者关键词:   aupt coreshell, electron pathway, fuel cell, graphene
  • 出版物名称:   ADVANCED ENERGY MATERIALS
  • ISSN:   1614-6832 EI 1614-6840
  • 通讯作者地址:   Tech Univ Denmark DTU
  • 被引频次:   17
  • DOI:   10.1002/aenm.201702609
  • 出版年:   2018

▎ 摘  要

Au-core/Pt-shell-graphene catalysts (G-Cys-Au@Pt) are prepared through chemical and surface chemical reactions. Au-Pt core-shell nanoparticles (Au@Pt NPs) covalently immobilized on graphene (G) are efficient electrocatalysts in low-temperature polymer electrolyte membrane fuel cells. The 9.5 +/- 2 nm Au@Pt NPs with atomically thin Pt shells are attached on graphene via l-cysteine (Cys), which serves as linkers controlling NP loading and dispersion, enhancing the Au@Pt NP stability, and facilitating interfacial electron transfer. The increased activity of G-Cys-Au@Pt, compared to non-chemically immobilized G-Au@Pt and commercial platinum NPs catalyst (C-Pt), is a result of (1) the tailored electron transfer pathways of covalent bonds integrating Au@Pt NPs into the graphene framework, and (2) synergetic electronic effects of atomically thin Pt shells on Au cores. Enhanced electrocatalytic oxidation of formic acid, methanol, and ethanol is observed as higher specific currents and increased stability of G-Cys-Au@Pt compared to G-Au@Pt and C-Pt. Oxygen reduction on G-Cys-Au@Pt occurs at 25 mV lower potential and 43 A g(Pt)(-1) higher current (at 0.9 V vs reversible hydrogen electrode) than for C-Pt. Functional tests in direct fomic acid, methanol and ethanol fuel cells exhibit 95%, 53%, and 107% increased power densities for G-Cys-Au@Pt over C-Pt, respectively.