Nanotubular Mesoporous PdCu Bimetallic Electrocatalysts toward Oxygen Reduction Reaction

Abstract

We describe the fabrication of novel PdCu bimetallic nanocomposites with hierarchically hollow structures through a simple galvanic replacement reaction using dealloyed nanoporous copper (NPC) as both a template and reducing agent. The reaction process was monitored by UV-vis absorbance spectra and X-ray diffraction (XRD), which clearly demonstrate a structure evolution from NPC precursor to a Pd-rich PdCu alloy structure upon the completion of the reaction. Structure characterization by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) indicates that the replacement reaction between NPC and [PdCl 4 ] 2-solution results in a nanotubular mesoporous structure with a nanoporous shell, which is comprised of interconnected alloy nanoparticles with size around 3 nm. The resulted PdCu nanostructure shows superior activity toward oxygen reduction reaction (ORR) with a half-wave potential at 0.840 V, which is significantly better than that of the commercial Pt/C catalyst.

Charge transfer effects on the chemical reactivity of PdxCu1−xnanoalloys

“…Most of these converters consist of electrocatalysts based on noble metal nanoparticles (NPs), such as Pt and Pd. [1][2][3][4][5][6] In this context, the synthesis and characterization of bimetallic or multimetallic NPs have attracted great interest, since they display novel physical and chemical properties, distinct from their monometallic counterparts. [7][8][9][10] Additionally, the properties of nanoalloys can be tuned by changing their size, atomic arrangement and composition.…”

“…PdCu bimetallic nanoalloys have been studied towards different catalytic reactions. [3][4][5][6]13,14 Mattei and coworkers 15 reported structural changes upon heating PdCu random nanoalloys embedded in silica, proving the formation of a Pdrich core surrounded by a CuO shell upon heating under an oxidizing atmosphere. They have also observed the Pd migration towards the NP surface upon heating under a reducing atmosphere.…”

Nanoporous PdNi Bimetallic Catalyst with Enhanced Electrocatalytic Performances for Electro-oxidation and Oxygen Reduction Reactions

“…[ 21 ] Moreover, nanotubular mesoporous PdCu catalyst, prepared by a galvanic replacement reaction, has been found to exhibit improved oxygen reduction activity, better than commercial Pt/C. [ 22 ] In this study, we report a nanoporous PdNi (np-PdNi) bimetallic catalyst fabricated by one-step electrochemically dealloying a Pd 20 Ni 80 alloy in an acid solution at an appropriate potential. The novel np-PdNi possesses superior catalytic properties in comparison with nanoporous Pd (np-Pd) formed at a high dealloying potential and commercial Pd/C, since the small organic molecule electro-oxidation and oxygen reduction activities on the np-PdNi catalysts are evidently enhanced by higher residual nickel contents.…”

Size and alloying induced shift in core and valence bands of Pd-Ag and Pd-Cu nanoparticles

“…5,6 The binary Pd-M (M ¼ Cu and Fe) systems have been identified as promising polymer electrolyte fuel cell (PEFC) cathode electrocatalysts, with enhanced activity for oxygen reduction reaction (ORR) and stability as compared to Pd alone. 7,8 The origin of the enhanced activity has been linked to modification of the electronic structure of Pd upon bonding with the alloying metal. 9 In addition to alloying, the structural and electronic properties of the Pd can also be tailored by reducing its dimensions.…”