Topic
Platinum
About: Platinum is a research topic. Over the lifetime, 49675 publications have been published within this topic receiving 1150035 citations. The topic is also known as: Pt & element 78.
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TL;DR: The particle size effect for oxygen reduction kinetics on highly dispersed Pt particles in acid electrolytes is discussed in this article, where it is suggested that the change in the fraction of surface atoms on the (100) and (111) crystal faces of Pt particles, which are assumed to be cubo-octahedral structures, can be correlated to the mass activity (A/g Pt) and specific activity (μA/cm2 Pt), and that the specific activity increases with an increase in particle size.
Abstract: The particle size effect for oxygen reduction kinetics on highly dispersed Pt particles in acid electrolytes are discussed. It is suggested that the change in the fraction of surface atoms on the (100) and (111) crystal faces of Pt particles, which are assumed to be cubo‐octahedral structures, can be correlated to the mass activity (A/g Pt) and specific activity (μA/cm2 Pt) of highly dispersed Pt electrocatalysts. The maximum in mass activity that is observed at ~3.5 nm in several studies is attributed to the maximum in the surface fraction of Pt atoms on the (100) and (111) crystal faces, which results from the change in surface coordination number with a change in the average particle size. The reduction of oxygen on supported Pt particles in acid electrolytes is classified as a demanding or structure‐sensitive reaction; the specific activity increases with an increase in particle size.
794 citations
TL;DR: Nanocages of platinum are fabricated by depositing a few atomic layers of platinum as conformal shells on palladium nanocrystals with well-defined facets and then etching away the Pd templates.
Abstract: A cost-effective catalyst should have a high dispersion of the active atoms, together with a controllable surface structure for the optimization of activity, selectivity, or both. We fabricated nanocages by depositing a few atomic layers of platinum (Pt) as conformal shells on palladium (Pd) nanocrystals with well-defined facets and then etching away the Pd templates. Density functional theory calculations suggest that the etching is initiated via a mechanism that involves the formation of vacancies through the removal of Pd atoms incorporated into the outermost layer during the deposition of Pt. With the use of Pd nanoscale cubes and octahedra as templates, we obtained Pt cubic and octahedral nanocages enclosed by {100} and {111} facets, respectively, which exhibited distinctive catalytic activities toward oxygen reduction.
793 citations
TL;DR: Using the rotating ring disk technique (RRDPt(hkl)E), the ORR was studied in sulfuric acid solution over the temperature range 298 −333 K at the same temperature, the exc...
Abstract: Using the rotating ring-disk technique (RRDPt(hkl)E), the oxygen-reduction reaction (ORR) was studied in sulfuric acid solution over the temperature range 298–333 K At the same temperature, the exc...
793 citations
DSM1
TL;DR: In this article, a review of ORR catalysts with regard to their classification, mechanism, activity and performances is presented, from conventional Pt-based catalysts to non-noble metal or bio-inspired catalysts.
Abstract: Fuel cell reactions invariably involve an oxygen reduction reaction (ORR) at the cathode, which is one of the main rate-decreasing steps on platinum (Pt)-catalysts in the water formation reaction and energy conversion efficiency in polymer electrolyte membrane fuel cells (PEMFCs). The Pt scarcity and cost have led to the development of alternative catalyst materials for fuel cell applications. This paper reviews ORR catalysts with regard to their classification, mechanism, activity and performances. From conventional Pt-based catalysts to non-noble metal or bio-inspired catalysts, we show how significant progresses were made in ORR catalysis.
792 citations
TL;DR: A number of chemical routes have been developed to produce Pt nanocrystals with well-defined and controllable shapes to improve their performance in terms of catalytic activity and selectivity as mentioned in this paper.
791 citations