Mesoporous hollow PtCu nanoparticles for electrocatalytic oxygen reduction reaction

Zhang²,

ACS Appl. Mater. Interfaces

et al. 2013

Self Cite

108

Palladium-Nickel (Pd-Ni) hollow nanoparticles were synthesized via a modified galvanic replacement method using Ni nanoparticles as sacrificial templates in an aqueous medium. X-ray diffraction and transmission electron microscopy show that the as-synthesized nanoparticles are alloyed nanostructures and have hollow interiors with an average particle size of 30 nm and shell thickness of 5 nm. Compared with the commercially available Pt/C or Pd/C catalysts, the synthesized PdNi/C has superior electrocatalytic performance towards the oxygen reduction reaction, which makes it a promising electrocatalyst for alkaline anion exchange membrane fuel cells and alkali-based air-batteries. The electrocatalyst is finally examined in an H2/O2 alkaline anion exchange membrane fuel cell; the results show that such electrocatalysts could work in a real fuel cell application as a more efficient catalyst than state-of-the-art commercially available Pt/C.

Section: Resultsmentioning

confidence: 99%

PdNi Hollow Nanoparticles for Improved Electrocatalytic Oxygen Reduction in Alkaline Environments

Zhang²,

ACS Appl. Mater. Interfaces

et al. 2013

Self Cite

108

“…[ 116,117 ] As demonstrated in our previous study, Au-Ag nanocages, prepared via the galvanic replacement between Ag nanocubes and HAuCl 4 , can be used as highly effective catalysts for redox reactions. [ 118 ] The study was motivated by the need to overcome the dilemma encountered with conventional solid catalytic nanoparticles used for redox reactions.…”

Section: Catalysismentioning

confidence: 98%

25th Anniversary Article: Galvanic Replacement: A Simple and Versatile Route to Hollow Nanostructures with Tunable and Well‐Controlled Properties

et al. 2013

This article provides a progress report on the use of galvanic replacement for generating complex hollow nanostructures with tunable and well-controlled properties. We begin with a brief account of the mechanistic understanding of galvanic replacement, specifically focused on its ability to engineer the properties of metal nanostructures in terms of size, composition, structure, shape, and morphology. We then discuss a number of important concepts involved in galvanic replacement, including the facet selectivity involved in the dissolution and deposition of metals, the impacts of alloying and dealloying on the structure and morphology of the final products, and methods for promoting or preventing a galvanic replacement reaction. We also illustrate how the capability of galvanic replacement can be enhanced to fabricate nanomaterials with complex structures and/or compositions by coupling with other processes such as co-reduction and the Kirkendall effect. Finally, we highlight the use of such novel metal nanostructures fabricated via galvanic replacement for applications ranging from catalysis to plasmonics and biomedical research, and conclude with remarks on prospective future directions.

“…Currently, Pt-based catalysts show the best ORR electrocatalytic performance, [3][4][5] but the prohibitive cost of such catalysts is their primary barrier to large-scale commercialisation. Therefore, it is important to develop efficient non-precious metal catalysts for practical applications.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of an ε-MnO₂/metal–organic-framework composite and its electrocatalysis towards oxygen reduction reaction in an alkaline electrolyte

et al. 2015

Electronic supplementary information (ESI) available: pore size distributions, EDX data, MOF(Fe) element mapping, C1s and O1s XPS spectra, RHE calibration, Electrochemical impedance spectra, MOF(Fe) CV curves, RDE voltammograms and corresponding K-L curves, MnO 2 ORR activities comparison, HORR and ORR catalytic activities comparison, and methanol crossover tests. AbstractAn ε-MnO 2 /metal-organic-framework(Fe) (i.e., ε-MnO 2 /MOF(Fe)) composite was synthesised by integrating ε-MnO 2 and a MOF(Fe) support. The composite was characterised using X-ray diffraction, N 2 adsorption-desorption, field emission scanning electron microscopy, transmission electron microscopy, element mapping, Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The ORR activity of the composite was evaluated by cyclic and linear sweep voltammetries in an alkaline electrolyte. The results revealed that in the ε-MnO 2 /MOF(Fe) composite, ε-MnO 2 are in the form of nanorods, each with one end protruding and the other firmly anchored on the MOF(Fe) matrix with a high porosity and a high specific surface area. This unique structure of the composite is advantageous for oxygen diffusion and contact with the ε-MnO 2 during reactions, resulting in much better ORR activity and stability than those of the ε-MnO 2 in an alkaline electrolyte. The ε-MnO 2 /MOF(Fe)-catalysed ORR favours an apparent 4-electron transfer pathway in which oxygen was firstly reduced to hydroperoxide, which was further chemically decomposed into primarily OH -and O 2 .