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Length-scale modulated and electrocatalytic activity enhanced nanoporous gold by doping
In the present paper, we have investigated the dealloying of Pt- and/or Pd-doped Al2Au intermetallic compounds and the formation of ultrafine nanoporous Au (np-Au) alloys through a chemical dealloying strategy. The microstructural characterization confirms that these doping atoms enter into crystal lattices of the precursors and then transmit into the as-obtained np-Au, both existing in the form of solid solutions. When dealloying in the 20 wt % NaOH solution is performed, a certain amount of Pt and/or Pd addition shows a superior refining effect and the ligament/channel sizes of the as-doped np-Au can be facilely modulated below 10 nm. When dealloying in the 5 wt % HCl solution is performed, however, the anticoarsening capacity of Pt doping is more remarkable compared with that of Pd doping. In addition, the amount of doping also has an important influence on the ligament resistance to coarsening. Apart from causing the refinement of ligaments/channels, the introduction of Pt and/or Pd into np-Au has generated novel bi- or trimetallic functionalized nanoporous alloys. These as-doped np-Au alloys with an appropriate amount of Pt and/or Pd exhibit excellent electrocatalytic activities toward methanol and formic acid oxidation and will find promising applications in the catalysis-related areas.