NTA system for nanoparticle characterization DTU Orbit (19/12/2018) The NanoChemistry group at th... more NTA system for nanoparticle characterization DTU Orbit (19/12/2018) The NanoChemistry group at the Technical University of Denmark (DTU) uses NanoSight’s NTA system for nanoparticle characterization Salisbury, UK, 7th December 2011: NanoSight, leading manufacturers of unique nanoparticle characterization technology, describes how the Nano Chemistry group at DTU Copenhagen is utilizing nanoparticle tracking analysis, NTA, in its research and teaching programs.
EICC_4_final.pdf Source: PublicationPreSubmission Source-ID: 128869804 Research output: Research ... more EICC_4_final.pdf Source: PublicationPreSubmission Source-ID: 128869804 Research output: Research peer-review › Conference abstract for conference – Annual report year: 2017
Graphene-glucose oxidase bioanodes for enzymatic biofuel cells Enzymatic biofuel cells (EBFCs) ar... more Graphene-glucose oxidase bioanodes for enzymatic biofuel cells Enzymatic biofuel cells (EBFCs) are electrochemical devices, that produce electricity from energy stored in fuel molecules under catalysis of enzymes. An EBFC contains a bioanode and/or a biocathode, in which enzymes are used to catalyse oxidation of fuel molecules such as sugars, and dioxygen reduction, respectively. The advantage of EBFCs is to generate energy from abundant fuel molecules without using expensive noble metals. On the other hand, development of EBFCs is still at the research stage due to instability of the biocatalysts. Here, we are developing a bioanode using graphene as supporting material, polyethyleneimine (PEI) as linker and glucose oxidase (GOD) as the chosen enzyme. GOD can catalyze oxidation of glucose to gluconolactone, but needs a mediator to assist electron transfer between the enzyme and electrodes. The redox molecule ferrocene carboxylic acid (FcCOOH) is immobilized together with GOD on the ...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ABSTRACT Transition metal phosphides are emerging as promising anode materials of sodium ion batt... more ABSTRACT Transition metal phosphides are emerging as promising anode materials of sodium ion batteries (SIBs) due to their high performance in terms of capacity and operational stability. Highly isolated CoP nanoparticles encapsulated in 3D hollow nitrogen-doped carbon networks (CoP/HNC composite) are designed via polymerization of poly-dopamine (PDA) on ZIF-67 and the subsequent in-situ phosphorization. Ultrafine CoP nanoparticles (10 ± 2 nm) are decorated in nitrogen-doped carbon polyhedral shells in a porous 3D hollow architecture. Benefiting from the unique construction, the CoP/HNC electrode delivers a high reversible long cycle-life capacity of 223 mA h g−1 for sodium storage at 500 mA g−1 after 700 cycles. DFT simulations indicate that Na atoms strongly bound to CoP surfaces, and significantly concentrate near CoP surfaces, beneficial for the Na atoms storage in this composite material. These results suggest the CoP/HNC composite can be a promising anode material for SIBs. Besides, the designed strategy of CoP/HNC composite could be applied to fabricate other metal phosphides for electrochemical storage devices.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The structure and ultrafast photodynamics of ∼8 nm Au@Pt core−shell nanocrystals with ultrathin (... more The structure and ultrafast photodynamics of ∼8 nm Au@Pt core−shell nanocrystals with ultrathin (<3 atomic layers) Pt−Au alloy shells are investigated to show that they meet the design principles for efficient bimetallic plasmonic photocatalysis. Photoelectron spectra recorded at two different photon energies are used to determine the radial concentration profile of the Pt−Au shell and the electron density near the Fermi energy, which play a key role in plasmon damping and electronic and thermal conductivity. Transient absorption measurements track the flow of energy from the plasmonic core to the electronic manifold of the Pt shell and back to the lattice of the core in the form of heat. We show that strong coupling to the high density of Pt(d) electrons at the Fermi level leads to accelerated dephasing of the Au plasmon on the femtosecond time scale, electron−electron energy transfer from Au(sp) core electrons to Pt(d) shell electrons on the subpicosecond time scale, and enhanced thermal resistance on the 50 ps time scale. Electron−electron scattering efficiently funnels hot carriers into the ultrathin catalytically active shell at the nanocrystal surface, making them available to drive chemical reactions before losing energy to the lattice via electron−phonon scattering on the 2 ps time scale. The combination of strong broadband light absorption, enhanced electromagnetic fields at the catalytic metal sites, and efficient delivery of hot carriers to the catalyst surface makes core−shell nanocrystals with plasmonic metal cores and ultrathin catalytic metal shells promising nanostructures for the realization of high-efficiency plasmonic catalysts.
Unique two-dimensional super-structures form when cysteine self-assembles on single-crystal Au(10... more Unique two-dimensional super-structures form when cysteine self-assembles on single-crystal Au(100) due to inter-molecular forces and adsorption energetics, addressed through a comprehensive experimental and quantum computational approach.
Byproducts in metal nanoparticle synthesis can interfere with nanomaterial formation and self-ass... more Byproducts in metal nanoparticle synthesis can interfere with nanomaterial formation and self-assembly, as well as the perceived nanomaterial properties. Such syntheses go through a complicated series of intermediates making it difficult to predict byproduct chemistry, and challenging to determine experimentally. By a combined experimental and theoretical approach, the formation of organic byproducts are mapped out for the synthesis of gold nanoparticles with the Good's buffer MES. Comprehensive nuclear magnetic resonance studies supported by mass spectrometry, ultraviolet-visible spectroscopy, and density functional theory reveal a number of previously unidentified byproducts formed by oxidation, C-N bond cleavage, and CC bond formation. A reaction mechanism involving up to four consecutive oxidations is proposed. Oligomeric products with 2 electronic transitions in the visible range are suggested. This approach can be extended broadly, and lead to more informed synthesis design and materials characterization.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
A new nanostructured mesoporous composite comprised of 75% iron oxide nanorods and 25% reduced gr... more A new nanostructured mesoporous composite comprised of 75% iron oxide nanorods and 25% reduced graphene oxide shows high electrochemical performances as a promising lithium-ion battery anode material.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Abstract Finding controllable, low-cost, and scalable ways to generate Ni-based catalysts is the ... more Abstract Finding controllable, low-cost, and scalable ways to generate Ni-based catalysts is the bottleneck for methane dry reforming catalyst design. A new method for generating trimetallic Co x Ni y Mg 100 − x − y O solid solution platelets enclosed by (1 1 1) facets has been developed from the topotactic pyrolysis of the metastable precursor Co x Ni y Mg 100 − x − y (OH)(OCH 3 ) derived from solvothermal synthesis. The catalyst composition and reaction conditions have been modulated to achieve maximum coke resistance and catalyst stability. Long-term stability for 1000 h time on stream at 800 °C has been achieved for the optimized Co 0.075 Ni 7.425 Mg 92.5 O catalyst. The role of Co in the catalyst has been disclosed through kinetic measurements and detailed characterization of the spent catalysts. Co is enriched on the Co–Ni alloy surface under reforming conditions and accelerates the gasification of coke intermediates. Co also enhances the chemisorption of oxygen and reduces the activation energy for methane fragmentation, which is the rate-determining step for the overall reaction.
NTA system for nanoparticle characterization DTU Orbit (19/12/2018) The NanoChemistry group at th... more NTA system for nanoparticle characterization DTU Orbit (19/12/2018) The NanoChemistry group at the Technical University of Denmark (DTU) uses NanoSight’s NTA system for nanoparticle characterization Salisbury, UK, 7th December 2011: NanoSight, leading manufacturers of unique nanoparticle characterization technology, describes how the Nano Chemistry group at DTU Copenhagen is utilizing nanoparticle tracking analysis, NTA, in its research and teaching programs.
EICC_4_final.pdf Source: PublicationPreSubmission Source-ID: 128869804 Research output: Research ... more EICC_4_final.pdf Source: PublicationPreSubmission Source-ID: 128869804 Research output: Research peer-review › Conference abstract for conference – Annual report year: 2017
Graphene-glucose oxidase bioanodes for enzymatic biofuel cells Enzymatic biofuel cells (EBFCs) ar... more Graphene-glucose oxidase bioanodes for enzymatic biofuel cells Enzymatic biofuel cells (EBFCs) are electrochemical devices, that produce electricity from energy stored in fuel molecules under catalysis of enzymes. An EBFC contains a bioanode and/or a biocathode, in which enzymes are used to catalyse oxidation of fuel molecules such as sugars, and dioxygen reduction, respectively. The advantage of EBFCs is to generate energy from abundant fuel molecules without using expensive noble metals. On the other hand, development of EBFCs is still at the research stage due to instability of the biocatalysts. Here, we are developing a bioanode using graphene as supporting material, polyethyleneimine (PEI) as linker and glucose oxidase (GOD) as the chosen enzyme. GOD can catalyze oxidation of glucose to gluconolactone, but needs a mediator to assist electron transfer between the enzyme and electrodes. The redox molecule ferrocene carboxylic acid (FcCOOH) is immobilized together with GOD on the ...
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ABSTRACT Transition metal phosphides are emerging as promising anode materials of sodium ion batt... more ABSTRACT Transition metal phosphides are emerging as promising anode materials of sodium ion batteries (SIBs) due to their high performance in terms of capacity and operational stability. Highly isolated CoP nanoparticles encapsulated in 3D hollow nitrogen-doped carbon networks (CoP/HNC composite) are designed via polymerization of poly-dopamine (PDA) on ZIF-67 and the subsequent in-situ phosphorization. Ultrafine CoP nanoparticles (10 ± 2 nm) are decorated in nitrogen-doped carbon polyhedral shells in a porous 3D hollow architecture. Benefiting from the unique construction, the CoP/HNC electrode delivers a high reversible long cycle-life capacity of 223 mA h g−1 for sodium storage at 500 mA g−1 after 700 cycles. DFT simulations indicate that Na atoms strongly bound to CoP surfaces, and significantly concentrate near CoP surfaces, beneficial for the Na atoms storage in this composite material. These results suggest the CoP/HNC composite can be a promising anode material for SIBs. Besides, the designed strategy of CoP/HNC composite could be applied to fabricate other metal phosphides for electrochemical storage devices.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
The structure and ultrafast photodynamics of ∼8 nm Au@Pt core−shell nanocrystals with ultrathin (... more The structure and ultrafast photodynamics of ∼8 nm Au@Pt core−shell nanocrystals with ultrathin (<3 atomic layers) Pt−Au alloy shells are investigated to show that they meet the design principles for efficient bimetallic plasmonic photocatalysis. Photoelectron spectra recorded at two different photon energies are used to determine the radial concentration profile of the Pt−Au shell and the electron density near the Fermi energy, which play a key role in plasmon damping and electronic and thermal conductivity. Transient absorption measurements track the flow of energy from the plasmonic core to the electronic manifold of the Pt shell and back to the lattice of the core in the form of heat. We show that strong coupling to the high density of Pt(d) electrons at the Fermi level leads to accelerated dephasing of the Au plasmon on the femtosecond time scale, electron−electron energy transfer from Au(sp) core electrons to Pt(d) shell electrons on the subpicosecond time scale, and enhanced thermal resistance on the 50 ps time scale. Electron−electron scattering efficiently funnels hot carriers into the ultrathin catalytically active shell at the nanocrystal surface, making them available to drive chemical reactions before losing energy to the lattice via electron−phonon scattering on the 2 ps time scale. The combination of strong broadband light absorption, enhanced electromagnetic fields at the catalytic metal sites, and efficient delivery of hot carriers to the catalyst surface makes core−shell nanocrystals with plasmonic metal cores and ultrathin catalytic metal shells promising nanostructures for the realization of high-efficiency plasmonic catalysts.
Unique two-dimensional super-structures form when cysteine self-assembles on single-crystal Au(10... more Unique two-dimensional super-structures form when cysteine self-assembles on single-crystal Au(100) due to inter-molecular forces and adsorption energetics, addressed through a comprehensive experimental and quantum computational approach.
Byproducts in metal nanoparticle synthesis can interfere with nanomaterial formation and self-ass... more Byproducts in metal nanoparticle synthesis can interfere with nanomaterial formation and self-assembly, as well as the perceived nanomaterial properties. Such syntheses go through a complicated series of intermediates making it difficult to predict byproduct chemistry, and challenging to determine experimentally. By a combined experimental and theoretical approach, the formation of organic byproducts are mapped out for the synthesis of gold nanoparticles with the Good's buffer MES. Comprehensive nuclear magnetic resonance studies supported by mass spectrometry, ultraviolet-visible spectroscopy, and density functional theory reveal a number of previously unidentified byproducts formed by oxidation, C-N bond cleavage, and CC bond formation. A reaction mechanism involving up to four consecutive oxidations is proposed. Oligomeric products with 2 electronic transitions in the visible range are suggested. This approach can be extended broadly, and lead to more informed synthesis design and materials characterization.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
A new nanostructured mesoporous composite comprised of 75% iron oxide nanorods and 25% reduced gr... more A new nanostructured mesoporous composite comprised of 75% iron oxide nanorods and 25% reduced graphene oxide shows high electrochemical performances as a promising lithium-ion battery anode material.
Users may download and print one copy of any publication from the public portal for the purpose... more Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Abstract Finding controllable, low-cost, and scalable ways to generate Ni-based catalysts is the ... more Abstract Finding controllable, low-cost, and scalable ways to generate Ni-based catalysts is the bottleneck for methane dry reforming catalyst design. A new method for generating trimetallic Co x Ni y Mg 100 − x − y O solid solution platelets enclosed by (1 1 1) facets has been developed from the topotactic pyrolysis of the metastable precursor Co x Ni y Mg 100 − x − y (OH)(OCH 3 ) derived from solvothermal synthesis. The catalyst composition and reaction conditions have been modulated to achieve maximum coke resistance and catalyst stability. Long-term stability for 1000 h time on stream at 800 °C has been achieved for the optimized Co 0.075 Ni 7.425 Mg 92.5 O catalyst. The role of Co in the catalyst has been disclosed through kinetic measurements and detailed characterization of the spent catalysts. Co is enriched on the Co–Ni alloy surface under reforming conditions and accelerates the gasification of coke intermediates. Co also enhances the chemisorption of oxygen and reduces the activation energy for methane fragmentation, which is the rate-determining step for the overall reaction.
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