The Nanoparticle Size Effect in Graphene Cutting: A “Pac‐Man” Mechanism

Qiu, Zongyang; Li, Song; Zhao, Jin; Li, Zhenyu; Yang, Jinlong

doi:10.1002/anie.201602541

Cited by 29 publications

(20 citation statements)

References 37 publications

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“…Specifically, the CC bonds in graphene nanopore edge can be greatly influenced by the adjacent Pt atoms, which weaken and distort the CC bonds, resulting in C atoms moving away from the graphene plane. The explanation we proposed here is similar to the “Pac‐Man” mechanism . The above MD simulations result enabled us to explain the experimental phenomenon we observed.…”

Section: Resultssupporting

confidence: 83%

Double Nanoporous Structure with Nanoporous PtFe Embedded in Graphene Nanopores: Highly Efficient Bifunctional Electrocatalysts for Hydrogen Evolution and Oxygen Reduction

Zhong

Wang

Zhuang

et al. 2016

Adv Materials Inter

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Pt‐based alloys are considered the universal choice among electrocatalysts for both hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). However, improving the electrocatalytic efficiency with the use of minimal amount of Pt is very challenging. A new strategy has been developed to fabricate a “double nanoporous” structure, in which nanoporous PtFe alloy (np‐PtFe) is embedded in nanoporous graphene (NPG), through in situ etching and acid leaching treatments. The np‐PtFe/NPG‐700 served as an effective bifunctional catalyst for both HER and ORR, exhibiting higher activity and stability than 20% Pt/C. Theoretical calculations reveal that the graphene nanopores not only play a vital role in improving the stability of the nanoporous PtFe alloy but also downshift the d‐band center of the PtFe alloy, thus improving the catalytic activity. The double nanoporous structure also provides numerous diffusion channels, which facilitated the mass and charge transport during HER and ORR.

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Section: Resultssupporting

confidence: 83%

Double Nanoporous Structure with Nanoporous PtFe Embedded in Graphene Nanopores: Highly Efficient Bifunctional Electrocatalysts for Hydrogen Evolution and Oxygen Reduction

Zhong

Wang

Zhuang

et al. 2016

Adv Materials Inter

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“…[5] TheNiNPs could break surface CÀCb onds.A tt he same time,w hen Ni NPs diffuse within the N-doped carbon matrix, the Ni atoms can be bound to the N-rich defects.A sar esult, Ni NPs are gradually eroded and finally transformed into an atomic dispersion. [6] This phenomenon is also found in noble metal systems. [7] As illustrated in Figure 1a,weselect aNCsupport with an average diameter of 200 nm obtained by as imple pyrolysis treatment of ZIF-8 ( Figure S1 in the Supporting Information) as as upport.…”

mentioning

confidence: 71%

“…[6] This phenomenon is also found in noble metal systems. [5] TheNiNPs could break surface CÀCb onds.A tt he same time,w hen Ni NPs diffuse within the N-doped carbon matrix, the Ni atoms can be bound to the N-rich defects.A sar esult, Ni NPs are gradually eroded and finally transformed into an atomic dispersion.…”

mentioning

confidence: 73%

In Situ Thermal Atomization To Convert Supported Nickel Nanoparticles into Surface‐Bound Nickel Single‐Atom Catalysts

et al. 2018

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The arrangement of the active sites on the surface of ac atalysts can reduce the problem of mass transfer and enhance the atom economy.H erein, supported Ni metal nanoparticles can be transformed to thermal stable Ni single atoms,mostly located on the surface of the support. Assisted by N-doped carbon with abundant defects,t his synthetic process not only transform the nanoparticles to single atoms,b ut also creates numerous pores to facilitate the contact of dissolved CO 2 and single Ni sites.The proposed mechanism is that the Ni nanoparticles could break surface CÀCb onds drill into the carbon matrix, leaving pores on the surface.W hen Ni nanoparticles are exposed to N-doped carbon, the strong coordination splits Ni atoms from Ni NPs.The Ni atoms are stabilized within the surface of carbon substrate.T he continuous loss of atomic Ni species from the NPs would finally result in atomization of Ni NPs.C O 2 electroreduction testing shows that the surface enriched with Ni single atoms delivers better performance than supported Ni NPs and other similar catalysts.Owing to the massive CO 2 production from consuming the carbon-based fuels,c limatic problems have been triggered, especially global warming and glaciers melting. [1] It is urgent to search for the efficient ways to decrease the CO 2 accumulation in air.R ecently,e lectroreduction of CO 2 has been regarded as ap romising approach to decrease CO 2 as well as convert it into the other useful raw materials,such as CO,C H 4 ,C 2 H 4 ,H COOH. [2] Thei deal CO 2 electroreduction heterogeneous catalyst should contain highly dispersed active species on the support and sufficient accessible surface to prevent the problem of the mass transfer.H ence,aporous support is adopted, which could not only stabilize the reactive sites but also guarantee the fast adsorption of reactants and desorption of products.R ecently,s ingle-atom catalysts have drawn much attention for the electroreduction of CO 2 owing to their electrochemical performances and atom economy. [3] However,t he main problem is that most of the synthetic methods for single-atoms catalysts are based on the bottomup strategy,i nw hich the metal ions are adsorbed on the defect-containing matrix and then reduced to form single atoms in the whole support. [4] Based on this bottom-up method, the porous supports are incapable of confining most of the atomic metal species to the surface as they cannot prevent the migration of metal within the support matrix. This will result in the homogeneous distribution of single metal sites within the entire matrix rather than on the surface,a nd results in of mass transportation issues and deactivation of the catalytic process.To tackle this challenge,w ed escribe an ovel top-down strategy,during which the Ni nanoparticles (NPs) distributed on the surface of defect-containing N-doped carbon (NC) supports can be transformed into Ni single atoms on the surface by at hermal diffusion mechanism, which is quite different to the previous reports through vaporizing the nanoparticles ...

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“…At the same time, when Ni NPs diffuse within the N‐doped carbon matrix, the Ni atoms can be bound to the N‐rich defects. As a result, Ni NPs are gradually eroded and finally transformed into an atomic dispersion . This phenomenon is also found in noble metal systems…”

Section: Figurementioning

confidence: 99%

In Situ Thermal Atomization To Convert Supported Nickel Nanoparticles into Surface‐Bound Nickel Single‐Atom Catalysts

et al. 2018

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The Nanoparticle Size Effect in Graphene Cutting: A “Pac‐Man” Mechanism

Cited by 29 publications

References 37 publications

Double Nanoporous Structure with Nanoporous PtFe Embedded in Graphene Nanopores: Highly Efficient Bifunctional Electrocatalysts for Hydrogen Evolution and Oxygen Reduction

Double Nanoporous Structure with Nanoporous PtFe Embedded in Graphene Nanopores: Highly Efficient Bifunctional Electrocatalysts for Hydrogen Evolution and Oxygen Reduction

In Situ Thermal Atomization To Convert Supported Nickel Nanoparticles into Surface‐Bound Nickel Single‐Atom Catalysts

In Situ Thermal Atomization To Convert Supported Nickel Nanoparticles into Surface‐Bound Nickel Single‐Atom Catalysts

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