Journal ArticleDOI
Compositional segregation in shaped Pt alloy nanoparticles and their structural behaviour during electrocatalysis
TLDR
The segregation and leaching mechanisms revealed here highlight the complexity with which shape-selective nanoalloys form and evolve under reactive conditions.Abstract:
Shape-selective monometallic nanocatalysts offer activity benefits based on structural sensitivity and high surface area. In bimetallic nanoalloys with well-defined shape, site-dependent metal surface segregation additionally affects the catalytic activity and stability. However, segregation on shaped alloy nanocatalysts and their atomic-scale evolution is largely unexplored. Exemplified by three octahedral PtxNi1-x alloy nanoparticle electrocatalysts with unique activity for the oxygen reduction reaction at fuel cell cathodes, we reveal an unexpected compositional segregation structure across the {111} facets using aberration-corrected scanning transmission electron microscopy and electron energy-loss spectroscopy. In contrast to theoretical predictions, the pristine PtxNi1-x nano-octahedra feature a Pt-rich frame along their edges and corners, whereas their Ni atoms are preferentially segregated in their {111} facet region. We follow their morphological and compositional evolution in electrochemical environments and correlate this with their exceptional catalytic activity. The octahedra preferentially leach in their facet centres and evolve into 'concave octahedra'. More generally, the segregation and leaching mechanisms revealed here highlight the complexity with which shape-selective nanoalloys form and evolve under reactive conditions.read more
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Journal ArticleDOI
Combining theory and experiment in electrocatalysis: Insights into materials design
Zhi Wei Seh,Zhi Wei Seh,Zhi Wei Seh,Jakob Kibsgaard,Jakob Kibsgaard,Jakob Kibsgaard,Colin F. Dickens,Colin F. Dickens,Ib Chorkendorff,Jens K. Nørskov,Jens K. Nørskov,Thomas F. Jaramillo,Thomas F. Jaramillo +12 more
TL;DR: A unified theoretical framework highlights the need for catalyst design strategies that selectively stabilize distinct reaction intermediates relative to each other, and opens up opportunities and approaches to develop higher-performance electrocatalysts for a wide range of reactions.
Journal ArticleDOI
Design of electrocatalysts for oxygen- and hydrogen-involving energy conversion reactions
TL;DR: The emphasis of this review is on the origin of the electrocatalytic activity of nanostructured catalysts toward a series of key clean energy conversion reactions by correlating the apparent electrode performance with their intrinsic electrochemical properties.
Journal ArticleDOI
Recent Advances in Electrocatalysts for Oxygen Reduction Reaction
TL;DR: This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core-shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts and metal-free catalysts.
Journal ArticleDOI
Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.
Lichen Liu,Avelino Corma +1 more
TL;DR: This Review will compare the results obtained from different systems and try to give a picture on how different types of metal species work in different reactions and give perspectives on the future directions toward better understanding of the catalytic behavior of different metal entities in a unifying manner.
Journal ArticleDOI
Highly Crystalline Multimetallic Nanoframes with Three-Dimensional Electrocatalytic Surfaces
Chen Chen,Yijin Kang,Ziyang Huo,Ziyang Huo,Zhongwei Zhu,Zhongwei Zhu,Wenyu Huang,Wenyu Huang,Huolin L. Xin,Joshua Snyder,Dongguo Li,Jeffrey A. Herron,Manos Mavrikakis,Miaofang Chi,Karren L. More,Yadong Li,Nenad M. Markovic,Gabor A. Somorjai,Gabor A. Somorjai,Peidong Yang,Vojislav R. Stamenkovic +20 more
TL;DR: A highly active and durable class of electrocatalysts is synthesized by exploiting the structural evolution of platinum-nickel (Pt-Ni) bimetallic nanocrystals by exploitingThe starting material, crystalline PtNi3 polyhedra, transforms in solution by interior erosion into Pt3Ni nanoframes with surfaces that offer three-dimensional molecular accessibility.
References
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Journal ArticleDOI
Nanostructured materials for advanced energy conversion and storage devices
Antonino S. Aricò,Peter G. Bruce,Bruno Scrosati,Jean-Marie Tarascon,Jean-Marie Tarascon,Walter van Schalkwijk +5 more
TL;DR: This review describes some recent developments in the discovery of nanoelectrolytes and nanoeLECTrodes for lithium batteries, fuel cells and supercapacitors and the advantages and disadvantages of the nanoscale in materials design for such devices.
Journal ArticleDOI
Electrocatalyst approaches and challenges for automotive fuel cells
TL;DR: Taking the step towards successful commercialization requires oxygen reduction electrocatalysts that meet exacting performance targets, and these catalyst systems will need to be highly durable, fault-tolerant and amenable to high-volume production with high yields and exceptional quality.
Journal ArticleDOI
Improved Oxygen Reduction Activity on Pt3Ni(111) via Increased Surface Site Availability
Vojislav R. Stamenkovic,Vojislav R. Stamenkovic,Ben Fowler,Bongjin Simon Mun,Guofeng Wang,Philip N. Ross,Chris Lucas,Nenad M. Markovic +7 more
TL;DR: It is demonstrated that the Pt3Ni( 111) surface is 10-fold more active for the ORR than the corresponding Pt(111) surface and 90-foldMore active than the current state-of-the-art Pt/C catalysts for PEMFC.
Journal ArticleDOI
Trends in electrocatalysis on extended and nanoscale Pt-bimetallic alloy surfaces
Vojislav R. Stamenkovic,Vojislav R. Stamenkovic,Bongjin Simon Mun,Bongjin Simon Mun,Matthias Arenz,Karl Johann Jakob Mayrhofer,Chris Lucas,Guofeng Wang,Philip N. Ross,Nenad M. Markovic +9 more
TL;DR: The electrocatalytic trends established for extended surfaces are used to explain the activity pattern of Pt(3)M nanocatalysts as well as to provide a fundamental basis for the catalytic enhancement of cathode catalysts.
Journal ArticleDOI
Alloys of platinum and early transition metals as oxygen reduction electrocatalysts
Jeffrey Greeley,Ifan E. L. Stephens,Alexander S. Bondarenko,Tobias Peter Johansson,Heine Anton Hansen,Thomas F. Jaramillo,Thomas F. Jaramillo,Jan Rossmeisl,Ib Chorkendorff,Jens K. Nørskov +9 more
TL;DR: A new set of ORR electrocatalysts consisting of Pd or Pt alloyed with early transition metals such as Sc or Y, identified using density functional theory calculations as being the most stable Pt- and Pd-based binary alloys with ORR activity likely to be better than Pt.
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